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class="vp-toc-list"><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#triggers-implementation">Triggers Implementation</a></li><li><ul class="vp-toc-list"><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#dependency">Dependency</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#programming-interfaces">Programming Interfaces</a></li><!----><!--]--></ul></li><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#triggers-management">Triggers Management</a></li><li><ul class="vp-toc-list"><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#trigger-states">Trigger States</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#register-triggers">Register Triggers</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#drop-triggers">Drop Triggers</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#start-triggers">Start Triggers</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#stop-triggers">Stop Triggers</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#show-all-registered-triggers">Show All Registered Triggers</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#user-authority-management">User Authority Management</a></li><!----><!--]--></ul></li><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#utilities">Utilities</a></li><li><ul class="vp-toc-list"><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#windowing-utility">Windowing Utility</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level3" href="#sink-utility">Sink Utility</a></li><!----><!--]--></ul></li><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#maven-project-example">Maven Project Example</a></li><!----><!--]--><!--[--><li class="vp-toc-item"><a class="route-link vp-toc-link level2" href="#important-notes-1">Important Notes</a></li><!----><!--]--></ul><div class="vp-toc-marker" style="top:-1.7rem;"></div></div><!--[--><!----><!--]--></aside></div><!--[--><!----><!--]--><div class="theme-hope-content"><h1 id="triggers" tabindex="-1"><a class="header-anchor" href="#triggers"><span>Triggers</span></a></h1><p>The trigger provides a mechanism for listening to changes in time series data. With user-defined logic, tasks such as alerting, data cleaning, and data forwarding can be conducted.</p><p>The trigger is implemented based on the reflection mechanism. Users can monitor data changes by implementing the Java interfaces. IoTDB allows users to dynamically register and drop triggers without restarting the server.</p><p>The document will help you learn to define and manage triggers.</p><h2 id="triggers-implementation" tabindex="-1"><a class="header-anchor" href="#triggers-implementation"><span>Triggers Implementation</span></a></h2><h3 id="dependency" tabindex="-1"><a class="header-anchor" href="#dependency"><span>Dependency</span></a></h3><p>You need to implement the trigger by writing a Java class, where the dependency shown below is required. If you use <a href="http://search.maven.org/" target="_blank" rel="noopener noreferrer">Maven<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a>, you can search for them directly from the <a href="http://search.maven.org/" target="_blank" rel="noopener noreferrer">Maven repository<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a>.</p><div class="language-xml line-numbers-mode" data-ext="xml" data-title="xml"><pre class="language-xml"><code><span class="token tag"><span class="token tag"><span class="token punctuation"><</span>dependency</span><span class="token punctuation">></span></span> |
| <span class="token tag"><span class="token tag"><span class="token punctuation"><</span>groupId</span><span class="token punctuation">></span></span>org.apache.iotdb<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>groupId</span><span class="token punctuation">></span></span> |
| <span class="token tag"><span class="token tag"><span class="token punctuation"><</span>artifactId</span><span class="token punctuation">></span></span>iotdb-server<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>artifactId</span><span class="token punctuation">></span></span> |
| <span class="token tag"><span class="token tag"><span class="token punctuation"><</span>version</span><span class="token punctuation">></span></span>0.13.0-SNAPSHOT<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>version</span><span class="token punctuation">></span></span> |
| <span class="token tag"><span class="token tag"><span class="token punctuation"><</span>scope</span><span class="token punctuation">></span></span>provided<span class="token tag"><span class="token tag"><span class="token punctuation"></</span>scope</span><span class="token punctuation">></span></span> |
| <span class="token tag"><span class="token tag"><span class="token punctuation"></</span>dependency</span><span class="token punctuation">></span></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Note that the dependency version should be correspondent to the target server version.</p><h3 id="programming-interfaces" tabindex="-1"><a class="header-anchor" href="#programming-interfaces"><span>Programming Interfaces</span></a></h3><p>To implement a trigger, you need to implement the <code>org.apache.iotdb.db.engine.trigger.api.Trigger</code> class.</p><p>This class provides two types of programming interfaces: <strong>life cycle hooks</strong> and <strong>data change listening hooks</strong>. All the interfaces in this class are not required to be implemented. When the interfaces are not implemented, the trigger will not respond to the data changes. You can implement only some of these interfaces according to your needs.</p><p>Descriptions of the interfaces are as followed.</p><h4 id="life-cycle-hooks" tabindex="-1"><a class="header-anchor" href="#life-cycle-hooks"><span>Life Cycle Hooks</span></a></h4><table><thead><tr><th style="text-align:left;">Interface Definition</th><th>Description</th></tr></thead><tbody><tr><td style="text-align:left;"><code>void onCreate(TriggerAttributes attributes) throws Exception</code></td><td>When you use the <code>CREATE TRIGGER</code> statement to register the trigger, the hook will be called. In the life cycle of each instance, the hook will and only will be called once. This hook mainly has the following functions: 1. To parse custom attributes in SQL statements (using <code>TriggerAttributes</code>). 2. To create or apply for resources, such as establishing external links, opening files, etc.</td></tr><tr><td style="text-align:left;"><code>void onDrop() throws Exception</code></td><td>When you use the <code>DROP TRIGGER</code> statement to drop the trigger, the hook will be called. In the life cycle of each instance, the hook will and only will be called once. The main function of this hook is to perform operations such as releasing resources.</td></tr><tr><td style="text-align:left;"><code>void onStart() throws Exception</code></td><td>This hook will be called when you use the <code>START TRIGGER</code> statement to manually start the trigger (whose state should be <code>STOPPED</code>).</td></tr><tr><td style="text-align:left;"><code>void onStop() throws Exception</code></td><td>This hook will be called when you use the <code>STOP TRIGGER</code> statement to manually stop the trigger (whose state should be <code>STARTED</code>).</td></tr></tbody></table><h4 id="data-change-listening-hooks" tabindex="-1"><a class="header-anchor" href="#data-change-listening-hooks"><span>Data Change Listening Hooks</span></a></h4><p>Currently, triggers can only listen for data insertion operations.</p><p>The timing of calling the data change listener hooks is explicitly specified in the <code>CREATE TRIGGER</code> statement rather than at the programming interface level.</p><h5 id="single-point-insertion-listening-hooks" tabindex="-1"><a class="header-anchor" href="#single-point-insertion-listening-hooks"><span>Single Point Insertion Listening Hooks</span></a></h5><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token class-name">Integer</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span> timestamp<span class="token punctuation">,</span> <span class="token class-name">Integer</span> value<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token class-name">Long</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span> timestamp<span class="token punctuation">,</span> <span class="token class-name">Long</span> value<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token class-name">Float</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span> timestamp<span class="token punctuation">,</span> <span class="token class-name">Float</span> value<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token class-name">Double</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span> timestamp<span class="token punctuation">,</span> <span class="token class-name">Double</span> value<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token class-name">Boolean</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span> timestamp<span class="token punctuation">,</span> <span class="token class-name">Boolean</span> value<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token class-name">Binary</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span> timestamp<span class="token punctuation">,</span> <span class="token class-name">Binary</span> value<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>For each data insertion in the registered time series, the trigger will call <code>fire</code> as a response. The input parameters <code>timestamp</code> and <code>value</code> are the time and value of the data point inserted this time. You can write any logic to process data in the <code>fire</code> hook.</p><p>Note that currently the return value of the hook is meaningless.</p><h5 id="batch-data-insertion-listening-hooks" tabindex="-1"><a class="header-anchor" href="#batch-data-insertion-listening-hooks"><span>Batch Data Insertion Listening Hooks</span></a></h5><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token keyword">float</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token keyword">float</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token keyword">double</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token keyword">double</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token keyword">boolean</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token keyword">boolean</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| <span class="token class-name">Binary</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token class-name">Binary</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>If you need to use the <code>insertTablet</code> interface or the <code>insertTablets</code> interface of the Session API, you can reduce the overhead of trigger calls by implementing the above batch data insertion listening hooks.</p><p>It is recommended that the behaviors of the batch data insertion listening hooks and the single point insertion listening hooks be consistent. The default implemetation of the listening hook for batch data insertion is as followed.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">default</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token keyword">int</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{</span> |
| <span class="token keyword">int</span> size <span class="token operator">=</span> timestamps<span class="token punctuation">.</span>length<span class="token punctuation">;</span> |
| <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> size<span class="token punctuation">;</span> <span class="token operator">++</span>i<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token function">fire</span><span class="token punctuation">(</span>timestamps<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">,</span> values<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| <span class="token keyword">return</span> values<span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Note that currently the return value of the hook is meaningless.</p><h4 id="important-notes" tabindex="-1"><a class="header-anchor" href="#important-notes"><span>Important Notes</span></a></h4><ul><li>Triggers registered on different time series are difference instances, so you can maintain states in triggers.</li><li>The states maintained by triggers will be cleared after the system stops (unless you persist the data by yourself). The states of the triggers will be default values after the system is restarted.</li><li>All hook calls of a trigger are serialized.</li></ul><h2 id="triggers-management" tabindex="-1"><a class="header-anchor" href="#triggers-management"><span>Triggers Management</span></a></h2><p>You can register, drop, start or stop a trigger instance through SQL statements, and you can also query all registered triggers through SQL statements.</p><h3 id="trigger-states" tabindex="-1"><a class="header-anchor" href="#trigger-states"><span>Trigger States</span></a></h3><p>Triggers have two states: <code>STARTED</code> and <code>STOPPED</code>. You can start or stop a trigger by executing <code>START TRIGGER</code> or <code>STOP TRIGGER</code>.</p><p>When the state of a trigger is <code>STOPPED</code>, it will not respond to the operations on the registered time series (such as inserting a data point), but all status (trigger variables), and registration information will be saved.</p><p>Note that the default state of the triggers registered by the <code>CREATE TRIGGER</code> statement is <code>STARTED</code>.</p><h3 id="register-triggers" tabindex="-1"><a class="header-anchor" href="#register-triggers"><span>Register Triggers</span></a></h3><p>A trigger can only be registered on an existing time series. Only one trigger can be registered for any time series.</p><p>The time series registered with the trigger will be listened to by the trigger. When there is a data change in the time series, the corresponding hook in the trigger will be called.</p><p>Registering a trigger can be carried out as follows:</p><ol><li><p>Implement a complete Trigger class. Assume that the full class name of this class is <code>org.apache.iotdb.db.engine.trigger.example.AlertListener</code>.</p></li><li><p>Pack the project into a JAR package. If you use Maven to manage the project, you can refer to the above Maven project example.</p></li><li><p>Put the JAR package in the directory <code>iotdb-server-0.13.0-SNAPSHOT/ext/trigger</code> (or a subdirectory of <code>iotdb-server-0.13.0-SNAPSHOT/ext/trigger</code>).</p><blockquote><p>You can specify the root path to load the trigger JAR packages by modifying the <code>trigger_root_dir</code> in the configuration file.</p></blockquote></li><li><p>Use the SQL statement to register the trigger. Assume that the name given to the trigger is <code>alert-listener-sg1d1s1</code>.</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">CREATE</span> <span class="token keyword">TRIGGER</span> <span class="token identifier"><span class="token punctuation">`</span>alert-listener-sg1d1s1<span class="token punctuation">`</span></span> |
| <span class="token keyword">AFTER</span> <span class="token keyword">INSERT</span> |
| <span class="token keyword">ON</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">.</span>s1 |
| <span class="token keyword">AS</span> <span class="token string">'org.apache.iotdb.db.engine.trigger.example.AlertListener'</span> |
| <span class="token keyword">WITH</span> <span class="token punctuation">(</span> |
| <span class="token string">'lo'</span> <span class="token operator">=</span> <span class="token string">'0'</span><span class="token punctuation">,</span> |
| <span class="token string">'hi'</span> <span class="token operator">=</span> <span class="token string">'100.0'</span> |
| <span class="token punctuation">)</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div></li></ol><p>The following shows the SQL syntax of registering a trigger.</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">CREATE</span> <span class="token keyword">TRIGGER</span> <span class="token operator"><</span><span class="token keyword">TRIGGER</span><span class="token operator">-</span>NAME<span class="token operator">></span> |
| <span class="token punctuation">(</span>BEFORE <span class="token operator">|</span> <span class="token keyword">AFTER</span><span class="token punctuation">)</span> <span class="token keyword">INSERT</span> |
| <span class="token keyword">ON</span> <span class="token operator"><</span><span class="token keyword">FULL</span><span class="token operator">-</span>PATH<span class="token operator">></span> |
| <span class="token keyword">AS</span> <span class="token operator"><</span>CLASSNAME<span class="token operator">></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>You can also set any number of key-value pair attributes for the trigger through the <code>WITH</code> clause:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">CREATE</span> <span class="token keyword">TRIGGER</span> <span class="token operator"><</span><span class="token keyword">TRIGGER</span><span class="token operator">-</span>NAME<span class="token operator">></span> |
| <span class="token punctuation">(</span>BEFORE <span class="token operator">|</span> <span class="token keyword">AFTER</span><span class="token punctuation">)</span> <span class="token keyword">INSERT</span> |
| <span class="token keyword">ON</span> <span class="token operator"><</span><span class="token keyword">FULL</span><span class="token operator">-</span>PATH<span class="token operator">></span> |
| <span class="token keyword">AS</span> <span class="token operator"><</span>CLASSNAME<span class="token operator">></span> |
| <span class="token keyword">WITH</span> <span class="token punctuation">(</span> |
| <span class="token operator"><</span><span class="token keyword">KEY</span><span class="token operator">-</span><span class="token number">1</span><span class="token operator">>=</span><span class="token operator"><</span><span class="token keyword">VALUE</span><span class="token operator">-</span><span class="token number">1</span><span class="token operator">></span><span class="token punctuation">,</span> |
| <span class="token operator"><</span><span class="token keyword">KEY</span><span class="token operator">-</span><span class="token number">2</span><span class="token operator">>=</span><span class="token operator"><</span><span class="token keyword">VALUE</span><span class="token operator">-</span><span class="token number">2</span><span class="token operator">></span><span class="token punctuation">,</span> |
| <span class="token punctuation">.</span><span class="token punctuation">.</span><span class="token punctuation">.</span> |
| <span class="token punctuation">)</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><code>TRIGGER-NAME</code> is a globally unique ID of the trigger, which is case sensitive.</p><p>At present, the trigger can listen to all data insertion operations on the time series. The hook can be called <code>BEFORE</code> or <code>AFTER</code> the data is inserted.</p><p><code>FULL-PATH</code> is the name of the time series that the trigger listens to. The path must be a measurement path.</p><p><code>CLASSNAME</code> is the full class name of the trigger.</p><p>Note that <code>CLASSNAME</code>, <code>KEY</code> and <code>VALUE</code> in the attributes need to be quoted in single or double quotes.</p><h3 id="drop-triggers" tabindex="-1"><a class="header-anchor" href="#drop-triggers"><span>Drop Triggers</span></a></h3><p>Triggers will be dropped in the following scenarios:</p><ol><li>When the user executes <code>DELETE TIMESERIES</code>, the triggers registered on the time series will be dropped.</li><li>When the user executes <code>DELETE STORAGE GROUP</code>, the triggers registered under the storage group will be dropped.</li><li>When the user executes the <code>DROP TRIGGER</code> statement.</li></ol><p>The following shows the SQL syntax of dropping a trigger:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">DROP</span> <span class="token keyword">TRIGGER</span> <span class="token operator"><</span><span class="token keyword">TRIGGER</span><span class="token operator">-</span>NAME<span class="token operator">></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The following is an example of a <code>DROP TRIGGER</code> statement:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">DROP</span> <span class="token keyword">TRIGGER</span> <span class="token identifier"><span class="token punctuation">`</span>alert-listener-sg1d1s1<span class="token punctuation">`</span></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h3 id="start-triggers" tabindex="-1"><a class="header-anchor" href="#start-triggers"><span>Start Triggers</span></a></h3><p>This operation changes the state of the trigger from <code>STOPPED</code> to <code>STARTED</code>, which will make the trigger re-listen to the operations on the registered time series and respond to data changes.</p><p>The following shows the SQL syntax of starting a trigger:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">START</span> <span class="token keyword">TRIGGER</span> <span class="token operator"><</span><span class="token keyword">TRIGGER</span><span class="token operator">-</span>NAME<span class="token operator">></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The following is an example of a <code>START TRIGGER</code> statement:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">START</span> <span class="token keyword">TRIGGER</span> <span class="token identifier"><span class="token punctuation">`</span>alert-listener-sg1d1s1<span class="token punctuation">`</span></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>Note that the triggers registered by the <code>CREATE TRIGGER</code> statements are <code>STARTED</code> by default.</p><h3 id="stop-triggers" tabindex="-1"><a class="header-anchor" href="#stop-triggers"><span>Stop Triggers</span></a></h3><p>This operation changes the state of the trigger from <code>STARTED</code> to <code>STOPPED</code>. When the status of a trigger is <code>STOPPED</code>, it will not respond to the operations on the registered time series (such as inserting a data point). You can restart a trigger using the <code>START TRIGGER</code> statement.</p><p>The following shows the SQL syntax of stopping a trigger:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code>STOP <span class="token keyword">TRIGGER</span> <span class="token operator"><</span><span class="token keyword">TRIGGER</span><span class="token operator">-</span>NAME<span class="token operator">></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p>The following is an example of a <code>STOP TRIGGER</code> statement:</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code>STOP <span class="token keyword">TRIGGER</span> <span class="token identifier"><span class="token punctuation">`</span>alert-listener-sg1d1s1<span class="token punctuation">`</span></span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h3 id="show-all-registered-triggers" tabindex="-1"><a class="header-anchor" href="#show-all-registered-triggers"><span>Show All Registered Triggers</span></a></h3><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">SHOW</span> TRIGGERS |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><h3 id="user-authority-management" tabindex="-1"><a class="header-anchor" href="#user-authority-management"><span>User Authority Management</span></a></h3><p>When a user manages triggers, 4 types of authorities will be involved:</p><ul><li><code>CREATE_TRIGGER</code>: Only users with this authority are allowed to register triggers. This authority is path dependent.</li><li><code>DROP_TRIGGER</code>: Only users with this authority are allowed to drop triggers. This authority is path dependent.</li><li><code>START_TRIGGER</code>: Only users with this authority are allowed to start triggers. This authority is path dependent.</li><li><code>STOP_TRIGGER</code>: Only users with this authority are allowed to stop triggers. This authority is path dependent.</li></ul><p>For more information, refer to <a class="route-link" href="/UserGuide/V0.13.x/Administration-Management/Administration.html">Authority Management Statement</a>.</p><h2 id="utilities" tabindex="-1"><a class="header-anchor" href="#utilities"><span>Utilities</span></a></h2><p>Utility classes provide programming paradigms and execution frameworks for the common requirements, which can simplify part of your work of implementing triggers.</p><h3 id="windowing-utility" tabindex="-1"><a class="header-anchor" href="#windowing-utility"><span>Windowing Utility</span></a></h3><p>The windowing utility can help you define sliding windows and the data processing logic on them. It can construct two types of sliding windows: one has a fixed time interval (<code>SlidingTimeWindowEvaluationHandler</code>), and the other has fixed number of data points (<code>SlidingSizeWindowEvaluationHandler</code>).</p><p>The windowing utility allows you to define a hook (<code>Evaluator</code>) on the window (<code>Window</code>). Whenever a new window is formed, the hook you defined will be called once. You can define any data processing-related logic in the hook. The call of the hook is asynchronous. Therefore, the current thread will not be blocked when the window processing logic is executed.</p><p>It is worth noting that whether it is <code>SlidingTimeWindowEvaluationHandler</code> or <code>SlidingSizeWindowEvaluationHandler</code>, <strong>they can only handle sequences with strictly monotonically increasing timestamps</strong>, and incoming data points that do not meet the requirements will be discarded.</p><p>For the definition of <code>Window</code> and <code>Evaluator</code>, please refer to the <code>org.apache.iotdb.db.utils.windowing.api</code> package.</p><h4 id="slidingsizewindowevaluationhandler" tabindex="-1"><a class="header-anchor" href="#slidingsizewindowevaluationhandler"><span>SlidingSizeWindowEvaluationHandler</span></a></h4><h5 id="window-construction" tabindex="-1"><a class="header-anchor" href="#window-construction"><span>Window Construction</span></a></h5><p>There are two construction methods.</p><p>The first method requires you to provide the type of data points that the window collects, the window size, the sliding step, and a hook (<code>Evaluator</code>).</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token class-name">TSDataType</span> dataType <span class="token operator">=</span> <span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">INT32</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">int</span> windowSize <span class="token operator">=</span> <span class="token number">10</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">int</span> slidingStep <span class="token operator">=</span> <span class="token number">5</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">SlidingSizeWindowEvaluationHandler</span> handler <span class="token operator">=</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingSizeWindowEvaluationHandler</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingSizeWindowConfiguration</span><span class="token punctuation">(</span>dataType<span class="token punctuation">,</span> windowSize<span class="token punctuation">,</span> slidingStep<span class="token punctuation">)</span><span class="token punctuation">,</span> |
| window <span class="token operator">-></span> <span class="token punctuation">{</span> |
| <span class="token comment">// do something</span> |
| <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The second method requires you to provide the type of data points that the window collects, the window size, and a hook (<code>Evaluator</code>). The sliding step is equal to the window size by default.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token class-name">TSDataType</span> dataType <span class="token operator">=</span> <span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">INT32</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">int</span> windowSize <span class="token operator">=</span> <span class="token number">10</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">SlidingSizeWindowEvaluationHandler</span> handler <span class="token operator">=</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingSizeWindowEvaluationHandler</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingSizeWindowConfiguration</span><span class="token punctuation">(</span>dataType<span class="token punctuation">,</span> windowSize<span class="token punctuation">)</span><span class="token punctuation">,</span> |
| window <span class="token operator">-></span> <span class="token punctuation">{</span> |
| <span class="token comment">// do something</span> |
| <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The window size and the sliding step must be positive.</p><h5 id="datapoint-collection" tabindex="-1"><a class="header-anchor" href="#datapoint-collection"><span>Datapoint Collection</span></a></h5><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token keyword">long</span> timestamp <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">int</span> value <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> |
| hander<span class="token punctuation">.</span><span class="token function">collect</span><span class="token punctuation">(</span>timestamp<span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Note that the type of the second parameter accepted by the <code>collect</code> method needs to be consistent with the <code>dataType</code> parameter provided during construction.</p><p>In addition, the <code>collect</code> method will only respond to data points whose timestamps are monotonically increasing. If the time stamp of the data point collected by the <code>collect</code> method is less than or equal to the time stamp of the data point collected by the previous <code>collect</code> method call, the data point collected this time will be discarded.</p><p>Also note that the <code>collect</code> method is not thread-safe.</p><h4 id="slidingtimewindowevaluationhandler" tabindex="-1"><a class="header-anchor" href="#slidingtimewindowevaluationhandler"><span>SlidingTimeWindowEvaluationHandler</span></a></h4><h5 id="window-construction-1" tabindex="-1"><a class="header-anchor" href="#window-construction-1"><span>Window Construction</span></a></h5><p>There are two construction methods.</p><p>The first method requires you to provide the type of data points that the window collects, the time interval, the sliding step, and a hook (<code>Evaluator</code>).</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token class-name">TSDataType</span> dataType <span class="token operator">=</span> <span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">INT32</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">long</span> timeInterval <span class="token operator">=</span> <span class="token number">1000</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">long</span> slidingStep <span class="token operator">=</span> <span class="token number">500</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">SlidingTimeWindowEvaluationHandler</span> handler <span class="token operator">=</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingTimeWindowEvaluationHandler</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingTimeWindowConfiguration</span><span class="token punctuation">(</span>dataType<span class="token punctuation">,</span> timeInterval<span class="token punctuation">,</span> slidingStep<span class="token punctuation">)</span><span class="token punctuation">,</span> |
| window <span class="token operator">-></span> <span class="token punctuation">{</span> |
| <span class="token comment">// do something</span> |
| <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The second method requires you to provide the type of data points that the window collects, the time interval, and a hook (<code>Evaluator</code>). The sliding step is equal to the time interval by default.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token class-name">TSDataType</span> dataType <span class="token operator">=</span> <span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">INT32</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">long</span> timeInterval <span class="token operator">=</span> <span class="token number">1000</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">SlidingTimeWindowEvaluationHandler</span> handler <span class="token operator">=</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingTimeWindowEvaluationHandler</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingTimeWindowConfiguration</span><span class="token punctuation">(</span>dataType<span class="token punctuation">,</span> timeInterval<span class="token punctuation">)</span><span class="token punctuation">,</span> |
| window <span class="token operator">-></span> <span class="token punctuation">{</span> |
| <span class="token comment">// do something</span> |
| <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The time interval and the sliding step must be positive.</p><h5 id="datapoint-collection-1" tabindex="-1"><a class="header-anchor" href="#datapoint-collection-1"><span>Datapoint Collection</span></a></h5><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token keyword">long</span> timestamp <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">int</span> value <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> |
| hander<span class="token punctuation">.</span><span class="token function">collect</span><span class="token punctuation">(</span>timestamp<span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Note that the type of the second parameter accepted by the <code>collect</code> method needs to be consistent with the <code>dataType</code> parameter provided during construction.</p><p>In addition, the <code>collect</code> method will only respond to data points whose timestamps are monotonically increasing. If the time stamp of the data point collected by the <code>collect</code> method is less than or equal to the time stamp of the data point collected by the previous <code>collect</code> method call, the data point collected this time will be discarded.</p><p>Also note that the <code>collect</code> method is not thread-safe.</p><h4 id="rejection-policy" tabindex="-1"><a class="header-anchor" href="#rejection-policy"><span>Rejection Policy</span></a></h4><p>The execution of window evaluation tasks is asynchronous.</p><p>When asynchronous tasks cannot be consumed by the execution thread pool in time, tasks will accumulate. In extreme cases, the accumulation of asynchronous tasks can cause the system OOM. Therefore, the number of tasks that the window evaluation thread pool allows to accumulate is set to a finite value.</p><p>When the number of accumulated tasks exceeds the limit, the newly submitted tasks will not be able to enter the thread pool for execution. At this time, the system will call the rejection policy hook <code>onRejection</code> that you have implemented in the listening hook (<code>Evaluator</code>) for processing.</p><p>The default behavior of <code>onRejection</code> is as follows.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">default</span> <span class="token keyword">void</span> <span class="token function">onRejection</span><span class="token punctuation">(</span><span class="token class-name">Window</span> window<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token keyword">throw</span> <span class="token keyword">new</span> <span class="token class-name">RejectedExecutionException</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>The way to implement a rejection strategy hook is as follows.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token class-name">SlidingTimeWindowEvaluationHandler</span> handler <span class="token operator">=</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingTimeWindowEvaluationHandler</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingTimeWindowConfiguration</span><span class="token punctuation">(</span><span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">INT32</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">1</span><span class="token punctuation">)</span><span class="token punctuation">,</span> |
| <span class="token keyword">new</span> <span class="token class-name">Evaluator</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">evaluate</span><span class="token punctuation">(</span><span class="token class-name">Window</span> window<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token comment">// do something</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">onRejection</span><span class="token punctuation">(</span><span class="token class-name">Window</span> window<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token comment">// do something</span> |
| <span class="token punctuation">}</span> |
| <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h4 id="configurable-properties" tabindex="-1"><a class="header-anchor" href="#configurable-properties"><span>Configurable Properties</span></a></h4><h5 id="concurrent-window-evaluation-thread" tabindex="-1"><a class="header-anchor" href="#concurrent-window-evaluation-thread"><span>concurrent_window_evaluation_thread</span></a></h5><p>The number of threads that can be used for evaluating sliding windows. The value is equals to CPU core number by default.</p><h5 id="max-pending-window-evaluation-tasks" tabindex="-1"><a class="header-anchor" href="#max-pending-window-evaluation-tasks"><span>max_pending_window_evaluation_tasks</span></a></h5><p>The maximum number of window evaluation tasks that can be pending for execution. The value is 64 by default.</p><h3 id="sink-utility" tabindex="-1"><a class="header-anchor" href="#sink-utility"><span>Sink Utility</span></a></h3><p>The sink utility provides the ability for triggers to connect to external systems.</p><p>It provides a programming paradigm. Each sink utility contains a <code>Handler</code> for processing data sending, a <code>Configuration</code> for configuring <code>Handler</code>, and an <code>Event</code> for describing the sending data.</p><h4 id="localiotdbsink" tabindex="-1"><a class="header-anchor" href="#localiotdbsink"><span>LocalIoTDBSink</span></a></h4><p><code>LocalIoTDBSink</code> is used to insert data points to the local sequence.</p><p>Before writing data, it is not required that the time series have been created.</p><p><strong>Note</strong>, in the scenario used for triggers, the listening time series and the written target time series should not be in the same storage group.</p><p>Example:</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token class-name">String</span> device <span class="token operator">=</span> <span class="token string">"root.alerting"</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> measurements <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token punctuation">{</span><span class="token string">"local"</span><span class="token punctuation">}</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">TSDataType</span><span class="token punctuation">[</span><span class="token punctuation">]</span> dataTypes <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">TSDataType</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token punctuation">{</span><span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">DOUBLE</span><span class="token punctuation">}</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">LocalIoTDBHandler</span> localIoTDBHandler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">LocalIoTDBHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| localIoTDBHandler<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">LocalIoTDBConfiguration</span><span class="token punctuation">(</span>device<span class="token punctuation">,</span> measurements<span class="token punctuation">,</span> dataTypes<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token comment">// insert 100 data points</span> |
| <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">100</span><span class="token punctuation">;</span> <span class="token operator">++</span>i<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token keyword">final</span> <span class="token keyword">long</span> timestamp <span class="token operator">=</span> i<span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">double</span> value <span class="token operator">=</span> i<span class="token punctuation">;</span> |
| localIoTDBHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">LocalIoTDBEvent</span><span class="token punctuation">(</span>timestamp<span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Note that when you need to insert data points to a time series of type <code>TEXT</code>, you need to use <code>org.apache.iotdb.tsfile.utils.Binary</code>:</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token comment">// insert 100 data points</span> |
| <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">100</span><span class="token punctuation">;</span> <span class="token operator">++</span>i<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token keyword">final</span> <span class="token keyword">long</span> timestamp <span class="token operator">=</span> i<span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">String</span> value <span class="token operator">=</span> <span class="token string">""</span> <span class="token operator">+</span> i<span class="token punctuation">;</span> |
| localIoTDBHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">LocalIoTDBEvent</span><span class="token punctuation">(</span>timestamp<span class="token punctuation">,</span> <span class="token class-name">Binary</span><span class="token punctuation">.</span><span class="token function">valueOf</span><span class="token punctuation">(</span>value<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h4 id="mqttsink" tabindex="-1"><a class="header-anchor" href="#mqttsink"><span>MQTTSink</span></a></h4><p>In triggers, you can use <code>MQTTSink</code> to send data points to other IoTDB instances.</p><p>Before sending data, it is not required that the time series have been created.</p><p>Example:</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">final</span> <span class="token class-name">String</span> host <span class="token operator">=</span> <span class="token string">"127.0.0.1"</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">int</span> port <span class="token operator">=</span> <span class="token number">1883</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">String</span> username <span class="token operator">=</span> <span class="token string">"root"</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">String</span> password <span class="token operator">=</span> <span class="token string">"root"</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">PartialPath</span> device <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">PartialPath</span><span class="token punctuation">(</span><span class="token string">"root.alerting"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> measurements <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token punctuation">{</span><span class="token string">"remote"</span><span class="token punctuation">}</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">MQTTHandler</span> mqttHandler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">MQTTHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| mqttHandler<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">MQTTConfiguration</span><span class="token punctuation">(</span>host<span class="token punctuation">,</span> port<span class="token punctuation">,</span> username<span class="token punctuation">,</span> password<span class="token punctuation">,</span> device<span class="token punctuation">,</span> measurements<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">final</span> <span class="token class-name">String</span> topic <span class="token operator">=</span> <span class="token string">"test"</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token class-name">QoS</span> qos <span class="token operator">=</span> <span class="token class-name">QoS</span><span class="token punctuation">.</span><span class="token constant">EXACTLY_ONCE</span><span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">boolean</span> retain <span class="token operator">=</span> <span class="token boolean">false</span><span class="token punctuation">;</span> |
| <span class="token comment">// send 100 data points</span> |
| <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> <span class="token number">100</span><span class="token punctuation">;</span> <span class="token operator">++</span>i<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token keyword">final</span> <span class="token keyword">long</span> timestamp <span class="token operator">=</span> i<span class="token punctuation">;</span> |
| <span class="token keyword">final</span> <span class="token keyword">double</span> value <span class="token operator">=</span> i<span class="token punctuation">;</span> |
| mqttHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">MQTTEvent</span><span class="token punctuation">(</span>topic<span class="token punctuation">,</span> qos<span class="token punctuation">,</span> retain<span class="token punctuation">,</span> timestamp<span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h4 id="alertmanagersink" tabindex="-1"><a class="header-anchor" href="#alertmanagersink"><span>AlertManagerSink</span></a></h4><p>In a trigger, you can use <code>AlertManagerSink</code> to send messages to AlertManager。</p><p>You need to specify the endpoint to send alerts of your AlertManager when constructing<br><code>AlertManagerConfiguration</code></p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token class-name">AlertManagerConfiguration</span><span class="token punctuation">(</span><span class="token class-name">String</span> endpoint<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div><p><code>AlertManagerEvent</code> offers three types of constructors：</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token class-name">AlertManagerEvent</span><span class="token punctuation">(</span><span class="token class-name">String</span> alertname<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token class-name">AlertManagerEvent</span><span class="token punctuation">(</span><span class="token class-name">String</span> alertname<span class="token punctuation">,</span> <span class="token class-name">Map</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">></span></span> extraLabels<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token class-name">AlertManagerEvent</span><span class="token punctuation">(</span><span class="token class-name">String</span> alertname<span class="token punctuation">,</span> <span class="token class-name">Map</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">></span></span> extraLabels<span class="token punctuation">,</span> <span class="token class-name">Map</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">></span></span> annotations<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><ul><li><code>alertname</code> is a required parameter to identify an <code>alert</code>. The <code>alertname</code> field can be used for grouping and deduplication when the <code>AlertManager</code> sends an alert.</li><li><code>extraLabels</code> is optional. In the backend, it is combined with <code>alertname</code> to form <code>labels</code> to identify an <code>alert</code>, which can be used for grouping and deduplication when <code>AlertManager</code> sends alarms.</li><li><code>annotations</code> is optional, and its value can use Go style template<div class="language-text line-numbers-mode" data-ext="text" data-title="text"><pre class="language-text"><code>{{.<label_key>}} |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div>It will be replaced with <code>labels[<label_key>]</code> when the message is finally generated.</li><li><code>labels</code> and <code>annotations</code> will be parsed into json string and sent to <code>AlertManager</code>:</li></ul><div class="language-json line-numbers-mode" data-ext="json" data-title="json"><pre class="language-json"><code><span class="token punctuation">{</span> |
| <span class="token property">"labels"</span><span class="token operator">:</span> <span class="token punctuation">{</span> |
| <span class="token property">"alertname"</span><span class="token operator">:</span> <span class="token string">"<requiredAlertName>"</span><span class="token punctuation">,</span> |
| <span class="token property">"<labelname>"</span><span class="token operator">:</span> <span class="token string">"<labelvalue>"</span><span class="token punctuation">,</span> |
| ... |
| <span class="token punctuation">}</span><span class="token punctuation">,</span> |
| <span class="token property">"annotations"</span><span class="token operator">:</span> <span class="token punctuation">{</span> |
| <span class="token property">"<labelname>"</span><span class="token operator">:</span> <span class="token string">"<labelvalue>"</span><span class="token punctuation">,</span> |
| ... |
| <span class="token punctuation">}</span> |
| <span class="token punctuation">}</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>Call the <code>onEvent(AlertManagerEvent event)</code> method of <code>AlertManagerHandler</code> to send an alert.</p><p><strong>Example 1:</strong></p><p>Only pass <code>alertname</code>.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token class-name">AlertManagerHandler</span> alertManagerHandler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">AlertManagerHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| alertManagerHandler<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">AlertManagerConfiguration</span><span class="token punctuation">(</span><span class="token string">"http://127.0.0.1:9093/api/v1/alerts"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">final</span> <span class="token class-name">String</span> alertName <span class="token operator">=</span> <span class="token string">"test0"</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">AlertManagerEvent</span> alertManagerEvent <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">AlertManagerEvent</span><span class="token punctuation">(</span>alertName<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| alertManagerHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span>alertManagerEvent<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><strong>Example 2：</strong></p><p>Pass <code>alertname</code> and <code>extraLabels</code>.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token class-name">AlertManagerHandler</span> alertManagerHandler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">AlertManagerHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| alertManagerHandler<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">AlertManagerConfiguration</span><span class="token punctuation">(</span><span class="token string">"http://127.0.0.1:9093/api/v1/alerts"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">final</span> <span class="token class-name">String</span> alertName <span class="token operator">=</span> <span class="token string">"test1"</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">final</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">></span></span> extraLabels <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| extraLabels<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"severity"</span><span class="token punctuation">,</span> <span class="token string">"critical"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| extraLabels<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"series"</span><span class="token punctuation">,</span> <span class="token string">"root.ln.wt01.wf01.temperature"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| extraLabels<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"value"</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">.</span><span class="token function">valueOf</span><span class="token punctuation">(</span><span class="token number">100.0</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token class-name">AlertManagerEvent</span> alertManagerEvent <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">AlertManagerEvent</span><span class="token punctuation">(</span>alertName<span class="token punctuation">,</span> extraLabels<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| alertManagerHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span>alertManagerEvent<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p><strong>Example 3：</strong></p><p>Pass <code>alertname</code>， <code>extraLabels</code> 和 <code>annotations</code>.</p><p>The final value of the <code>description</code> field will be parsed as <code>test2: root.ln.wt01.wf01.temperature is 100.0</code>.</p><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token class-name">AlertManagerHandler</span> alertManagerHandler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">AlertManagerHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| alertManagerHandler<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">AlertManagerConfiguration</span><span class="token punctuation">(</span><span class="token string">"http://127.0.0.1:9093/api/v1/alerts"</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">final</span> <span class="token class-name">String</span> alertName <span class="token operator">=</span> <span class="token string">"test2"</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">final</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">></span></span> extraLabels <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| extraLabels<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"severity"</span><span class="token punctuation">,</span> <span class="token string">"critical"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| extraLabels<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"series"</span><span class="token punctuation">,</span> <span class="token string">"root.ln.wt01.wf01.temperature"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| extraLabels<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"value"</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">.</span><span class="token function">valueOf</span><span class="token punctuation">(</span><span class="token number">100.0</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">final</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation"><</span><span class="token class-name">String</span><span class="token punctuation">,</span> <span class="token class-name">String</span><span class="token punctuation">></span></span> annotations <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">HashMap</span><span class="token generics"><span class="token punctuation"><</span><span class="token punctuation">></span></span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| annotations<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"summary"</span><span class="token punctuation">,</span> <span class="token string">"high temperature"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| annotations<span class="token punctuation">.</span><span class="token function">put</span><span class="token punctuation">(</span><span class="token string">"description"</span><span class="token punctuation">,</span> <span class="token string">"{{.alertname}}: {{.series}} is {{.value}}"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| alertManagerHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">AlertManagerEvent</span><span class="token punctuation">(</span>alertName<span class="token punctuation">,</span> extraLabels<span class="token punctuation">,</span> annotations<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><h2 id="maven-project-example" tabindex="-1"><a class="header-anchor" href="#maven-project-example"><span>Maven Project Example</span></a></h2><p>If you use <a href="http://search.maven.org/" target="_blank" rel="noopener noreferrer">Maven<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a>, you can refer to our sample project <strong>trigger-example</strong>.</p><p>You can find it <a href="https://github.com/apache/iotdb/tree/master/example/trigger" target="_blank" rel="noopener noreferrer">here<span><svg class="external-link-icon" xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path><polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg><span class="external-link-icon-sr-only">open in new window</span></span></a>.</p><p>It shows:</p><ul><li>How to use Maven to manage your trigger project</li><li>How to listen to data changes based on the user programming interface</li><li>How to use the windowing utility</li><li>How to use the sink utility</li></ul><div class="language-java line-numbers-mode" data-ext="java" data-title="java"><pre class="language-java"><code><span class="token keyword">package</span> <span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>trigger</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>api<span class="token punctuation">.</span></span><span class="token class-name">Trigger</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>api<span class="token punctuation">.</span></span><span class="token class-name">TriggerAttributes</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>metadata<span class="token punctuation">.</span>path<span class="token punctuation">.</span></span><span class="token class-name">PartialPath</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>sink<span class="token punctuation">.</span>mqtt<span class="token punctuation">.</span></span><span class="token class-name">MQTTConfiguration</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>sink<span class="token punctuation">.</span>mqtt<span class="token punctuation">.</span></span><span class="token class-name">MQTTEvent</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>sink<span class="token punctuation">.</span>mqtt<span class="token punctuation">.</span></span><span class="token class-name">MQTTHandler</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>sink<span class="token punctuation">.</span>local<span class="token punctuation">.</span></span><span class="token class-name">LocalIoTDBConfiguration</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>sink<span class="token punctuation">.</span>local<span class="token punctuation">.</span></span><span class="token class-name">LocalIoTDBEvent</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>engine<span class="token punctuation">.</span>trigger<span class="token punctuation">.</span>sink<span class="token punctuation">.</span>local<span class="token punctuation">.</span></span><span class="token class-name">LocalIoTDBHandler</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>utils<span class="token punctuation">.</span>windowing<span class="token punctuation">.</span>configuration<span class="token punctuation">.</span></span><span class="token class-name">SlidingSizeWindowConfiguration</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>db<span class="token punctuation">.</span>utils<span class="token punctuation">.</span>windowing<span class="token punctuation">.</span>handler<span class="token punctuation">.</span></span><span class="token class-name">SlidingSizeWindowEvaluationHandler</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>apache<span class="token punctuation">.</span>iotdb<span class="token punctuation">.</span>tsfile<span class="token punctuation">.</span>file<span class="token punctuation">.</span>metadata<span class="token punctuation">.</span>enums<span class="token punctuation">.</span></span><span class="token class-name">TSDataType</span></span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>fusesource<span class="token punctuation">.</span>mqtt<span class="token punctuation">.</span>client<span class="token punctuation">.</span></span><span class="token class-name">QoS</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>slf4j<span class="token punctuation">.</span></span><span class="token class-name">Logger</span></span><span class="token punctuation">;</span> |
| <span class="token keyword">import</span> <span class="token import"><span class="token namespace">org<span class="token punctuation">.</span>slf4j<span class="token punctuation">.</span></span><span class="token class-name">LoggerFactory</span></span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">public</span> <span class="token keyword">class</span> <span class="token class-name">TriggerExample</span> <span class="token keyword">implements</span> <span class="token class-name">Trigger</span> <span class="token punctuation">{</span> |
| |
| <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">final</span> <span class="token class-name">Logger</span> <span class="token constant">LOGGER</span> <span class="token operator">=</span> <span class="token class-name">LoggerFactory</span><span class="token punctuation">.</span><span class="token function">getLogger</span><span class="token punctuation">(</span><span class="token class-name">TriggerExample</span><span class="token punctuation">.</span><span class="token keyword">class</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">private</span> <span class="token keyword">static</span> <span class="token keyword">final</span> <span class="token class-name">String</span> <span class="token constant">TARGET_DEVICE</span> <span class="token operator">=</span> <span class="token string">"root.alerting"</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">private</span> <span class="token keyword">final</span> <span class="token class-name">LocalIoTDBHandler</span> localIoTDBHandler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">LocalIoTDBHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">private</span> <span class="token keyword">final</span> <span class="token class-name">MQTTHandler</span> mqttHandler <span class="token operator">=</span> <span class="token keyword">new</span> <span class="token class-name">MQTTHandler</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">private</span> <span class="token class-name">SlidingSizeWindowEvaluationHandler</span> windowEvaluationHandler<span class="token punctuation">;</span> |
| |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">onCreate</span><span class="token punctuation">(</span><span class="token class-name">TriggerAttributes</span> attributes<span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{</span> |
| <span class="token constant">LOGGER</span><span class="token punctuation">.</span><span class="token function">info</span><span class="token punctuation">(</span><span class="token string">"onCreate(TriggerAttributes attributes)"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">double</span> lo <span class="token operator">=</span> attributes<span class="token punctuation">.</span><span class="token function">getDouble</span><span class="token punctuation">(</span><span class="token string">"lo"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">double</span> hi <span class="token operator">=</span> attributes<span class="token punctuation">.</span><span class="token function">getDouble</span><span class="token punctuation">(</span><span class="token string">"hi"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token function">openSinkHandlers</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| windowEvaluationHandler <span class="token operator">=</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingSizeWindowEvaluationHandler</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">SlidingSizeWindowConfiguration</span><span class="token punctuation">(</span><span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">DOUBLE</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">5</span><span class="token punctuation">)</span><span class="token punctuation">,</span> |
| window <span class="token operator">-></span> <span class="token punctuation">{</span> |
| <span class="token keyword">double</span> avg <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> |
| <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> window<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token operator">++</span>i<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| avg <span class="token operator">+=</span> window<span class="token punctuation">.</span><span class="token function">getDouble</span><span class="token punctuation">(</span>i<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| avg <span class="token operator">/=</span> window<span class="token punctuation">.</span><span class="token function">size</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">if</span> <span class="token punctuation">(</span>avg <span class="token operator"><</span> lo <span class="token operator">||</span> hi <span class="token operator"><</span> avg<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| localIoTDBHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span><span class="token keyword">new</span> <span class="token class-name">LocalIoTDBEvent</span><span class="token punctuation">(</span>window<span class="token punctuation">.</span><span class="token function">getTime</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">,</span> avg<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| mqttHandler<span class="token punctuation">.</span><span class="token function">onEvent</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">MQTTEvent</span><span class="token punctuation">(</span><span class="token string">"test"</span><span class="token punctuation">,</span> <span class="token class-name">QoS</span><span class="token punctuation">.</span><span class="token constant">EXACTLY_ONCE</span><span class="token punctuation">,</span> <span class="token boolean">false</span><span class="token punctuation">,</span> window<span class="token punctuation">.</span><span class="token function">getTime</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">,</span> avg<span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| <span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">onDrop</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{</span> |
| <span class="token constant">LOGGER</span><span class="token punctuation">.</span><span class="token function">info</span><span class="token punctuation">(</span><span class="token string">"onDrop()"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token function">closeSinkHandlers</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">onStart</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{</span> |
| <span class="token constant">LOGGER</span><span class="token punctuation">.</span><span class="token function">info</span><span class="token punctuation">(</span><span class="token string">"onStart()"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token function">openSinkHandlers</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">onStop</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{</span> |
| <span class="token constant">LOGGER</span><span class="token punctuation">.</span><span class="token function">info</span><span class="token punctuation">(</span><span class="token string">"onStop()"</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token function">closeSinkHandlers</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token class-name">Double</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span> timestamp<span class="token punctuation">,</span> <span class="token class-name">Double</span> value<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| windowEvaluationHandler<span class="token punctuation">.</span><span class="token function">collect</span><span class="token punctuation">(</span>timestamp<span class="token punctuation">,</span> value<span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">return</span> value<span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token annotation punctuation">@Override</span> |
| <span class="token keyword">public</span> <span class="token keyword">double</span><span class="token punctuation">[</span><span class="token punctuation">]</span> <span class="token function">fire</span><span class="token punctuation">(</span><span class="token keyword">long</span><span class="token punctuation">[</span><span class="token punctuation">]</span> timestamps<span class="token punctuation">,</span> <span class="token keyword">double</span><span class="token punctuation">[</span><span class="token punctuation">]</span> values<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| <span class="token keyword">for</span> <span class="token punctuation">(</span><span class="token keyword">int</span> i <span class="token operator">=</span> <span class="token number">0</span><span class="token punctuation">;</span> i <span class="token operator"><</span> timestamps<span class="token punctuation">.</span>length<span class="token punctuation">;</span> <span class="token operator">++</span>i<span class="token punctuation">)</span> <span class="token punctuation">{</span> |
| windowEvaluationHandler<span class="token punctuation">.</span><span class="token function">collect</span><span class="token punctuation">(</span>timestamps<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">,</span> values<span class="token punctuation">[</span>i<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| <span class="token keyword">return</span> values<span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">openSinkHandlers</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{</span> |
| localIoTDBHandler<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">LocalIoTDBConfiguration</span><span class="token punctuation">(</span> |
| <span class="token constant">TARGET_DEVICE</span><span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">{</span><span class="token string">"local"</span><span class="token punctuation">}</span><span class="token punctuation">,</span> <span class="token keyword">new</span> <span class="token class-name">TSDataType</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">{</span><span class="token class-name">TSDataType</span><span class="token punctuation">.</span><span class="token constant">DOUBLE</span><span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| mqttHandler<span class="token punctuation">.</span><span class="token keyword">open</span><span class="token punctuation">(</span> |
| <span class="token keyword">new</span> <span class="token class-name">MQTTConfiguration</span><span class="token punctuation">(</span> |
| <span class="token string">"127.0.0.1"</span><span class="token punctuation">,</span> |
| <span class="token number">1883</span><span class="token punctuation">,</span> |
| <span class="token string">"root"</span><span class="token punctuation">,</span> |
| <span class="token string">"root"</span><span class="token punctuation">,</span> |
| <span class="token keyword">new</span> <span class="token class-name">PartialPath</span><span class="token punctuation">(</span><span class="token constant">TARGET_DEVICE</span><span class="token punctuation">)</span><span class="token punctuation">,</span> |
| <span class="token keyword">new</span> <span class="token class-name">String</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">{</span><span class="token string">"remote"</span><span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| |
| <span class="token keyword">private</span> <span class="token keyword">void</span> <span class="token function">closeSinkHandlers</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">throws</span> <span class="token class-name">Exception</span> <span class="token punctuation">{</span> |
| localIoTDBHandler<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| mqttHandler<span class="token punctuation">.</span><span class="token function">close</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token punctuation">}</span> |
| <span class="token punctuation">}</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div><p>You can try this trigger by following the steps below:</p><ul><li><p>Enable MQTT service by modifying <code>iotdb-engine.properties</code></p><div class="language-properties line-numbers-mode" data-ext="properties" data-title="properties"><pre class="language-properties"><code><span class="token comment"># whether to enable the mqtt service.</span> |
| <span class="token key attr-name">enable_mqtt_service</span><span class="token punctuation">=</span><span class="token value attr-value">true</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div></div></div></li><li><p>Start the IoTDB server</p></li><li><p>Create time series via cli</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">CREATE</span> TIMESERIES root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">.</span>s1 <span class="token keyword">WITH</span> DATATYPE<span class="token operator">=</span><span class="token keyword">DOUBLE</span><span class="token punctuation">,</span> ENCODING<span class="token operator">=</span>PLAIN<span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div></li><li><p>Place the JAR (<code>trigger-example-0.13.0-SNAPSHOT.jar</code>) of <strong>trigger-example</strong> in the directory <code>iotdb-server-0.13.0-SNAPSHOT/ext/trigger</code> (or in a subdirectory of <code>iotdb-server-0.13.0-SNAPSHOT/ext/trigger</code>)</p><blockquote><p>You can specify the root path to load the trigger JAR package by modifying the <code>trigger_root_dir</code> in the configuration file.</p></blockquote></li><li><p>Use the SQL statement to register the trigger, assuming that the name given to the trigger is <code>window-avg-alerter</code></p></li><li><p>Use the <code>CREATE TRIGGER</code> statement to register the trigger via cli</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">CREATE</span> <span class="token keyword">TRIGGER</span> <span class="token identifier"><span class="token punctuation">`</span>window-avg-alerter<span class="token punctuation">`</span></span> |
| <span class="token keyword">AFTER</span> <span class="token keyword">INSERT</span> |
| <span class="token keyword">ON</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">.</span>s1 |
| <span class="token keyword">AS</span> <span class="token string">'org.apache.iotdb.trigger.TriggerExample'</span> |
| <span class="token keyword">WITH</span> <span class="token punctuation">(</span> |
| <span class="token string">'lo'</span> <span class="token operator">=</span> <span class="token string">'0'</span><span class="token punctuation">,</span> |
| <span class="token string">'hi'</span> <span class="token operator">=</span> <span class="token string">'10.0'</span> |
| <span class="token punctuation">)</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div></li><li><p>Use cli to insert test data</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> <span class="token number">2</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">3</span><span class="token punctuation">,</span> <span class="token number">4</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">4</span><span class="token punctuation">,</span> <span class="token number">6</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">5</span><span class="token punctuation">,</span> <span class="token number">8</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">6</span><span class="token punctuation">,</span> <span class="token number">10</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">7</span><span class="token punctuation">,</span> <span class="token number">12</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">8</span><span class="token punctuation">,</span> <span class="token number">14</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">9</span><span class="token punctuation">,</span> <span class="token number">16</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| <span class="token keyword">INSERT</span> <span class="token keyword">INTO</span> root<span class="token punctuation">.</span>sg1<span class="token punctuation">.</span>d1<span class="token punctuation">(</span><span class="token keyword">timestamp</span><span class="token punctuation">,</span> s1<span class="token punctuation">)</span> <span class="token keyword">VALUES</span> <span class="token punctuation">(</span><span class="token number">10</span><span class="token punctuation">,</span> <span class="token number">18</span><span class="token punctuation">)</span><span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div></li><li><p>Use cli to query data to verify the behavior of the trigger</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code><span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> root<span class="token punctuation">.</span>alerting<span class="token punctuation">;</span> |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div></div></div></li><li><p>Under normal circumstances, the following results should be shown</p><div class="language-sql line-numbers-mode" data-ext="sql" data-title="sql"><pre class="language-sql"><code>IoTDB<span class="token operator">></span> <span class="token keyword">SELECT</span> <span class="token operator">*</span> <span class="token keyword">FROM</span> root<span class="token punctuation">.</span>alerting<span class="token punctuation">;</span> |
| <span class="token operator">+</span><span class="token comment">-----------------------------+--------------------+-------------------+</span> |
| <span class="token operator">|</span> <span class="token keyword">Time</span><span class="token operator">|</span>root<span class="token punctuation">.</span>alerting<span class="token punctuation">.</span>remote<span class="token operator">|</span>root<span class="token punctuation">.</span>alerting<span class="token punctuation">.</span><span class="token keyword">local</span><span class="token operator">|</span> |
| <span class="token operator">+</span><span class="token comment">-----------------------------+--------------------+-------------------+</span> |
| <span class="token operator">|</span><span class="token number">1970</span><span class="token operator">-</span><span class="token number">01</span><span class="token operator">-</span><span class="token number">01</span>T08:<span class="token number">00</span>:<span class="token number">00.006</span><span class="token operator">+</span><span class="token number">08</span>:<span class="token number">00</span><span class="token operator">|</span> <span class="token number">14.0</span><span class="token operator">|</span> <span class="token number">14.0</span><span class="token operator">|</span> |
| <span class="token operator">+</span><span class="token comment">-----------------------------+--------------------+-------------------+</span> |
| Total line number <span class="token operator">=</span> <span class="token number">1</span> |
| It costs <span class="token number">0.006</span>s |
| </code></pre><div class="line-numbers" aria-hidden="true"><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div><div class="line-number"></div></div></div></li></ul><p>That's all, please enjoy it 😄</p><h2 id="important-notes-1" tabindex="-1"><a class="header-anchor" href="#important-notes-1"><span>Important Notes</span></a></h2><ul><li><p>The trigger is implemented based on the reflection mechanism. Triggers can be dynamically registered and dropped without restarting the server.</p></li><li><p>It is best not to have classes with the same full class name but different function implementations in different JAR packages under <code>trigger_root_dir</code>. For example: the triggers <code>trigger1</code> and <code>trigger2</code> correspond to <code>trigger1.jar</code> and <code>trigger2.jar</code> respectively. If both JAR packages contain a <code>org.apache.iotdb.db.engine.trigger.example.AlertListener</code> class, when this class is used by a <code>CREATE TRIGGER</code> statement, the system will randomly load the class in one of the JAR packages, which may lead to inconsistent trigger behaviors and other problems.</p></li><li><p>Version management of trigger classes with the same full class name. Triggers with the same full class name but different versions (logic) are not allowed to register in the system.</p><p>Related question: IoTDB pre-registered 10 <code>org.apache.iotdb.db.engine.trigger.example.AlertListener</code> trigger instances and DBA updated the implementation and corresponding JAR package of <code>org.apache.iotdb.db.engine.trigger.example.AlertListener</code>. Is it possible to drop only 5 of the instances and replace them with 5 updated trigger instances?</p><p>Answer: No. Only by dropping all the 10 pre-registered triggers can you register the updated triggers. 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