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| <h1 class="title">Txn - A library for working with Transactions</h1> |
| |
| |
| <main class="d-flex flex-xl-row flex-column"> |
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| <aside class="text-muted align-self-start mb-3 p-0 d-xl-none d-block"> |
| <h2 class="h6 sticky-top m-0 p-2 bg-body-tertiary">On this page</h2> |
| <nav id="TableOfContents"> |
| <ul> |
| <li><a href="#transactions">Transactions</a></li> |
| <li><a href="#usage">Usage</a></li> |
| <li><a href="#working-with-rdf-models">Working with RDF Models</a></li> |
| <li><a href="#autocommit-and-transaction-continuation">Autocommit and Transaction continuation</a></li> |
| <li><a href="#design">Design</a></li> |
| </ul> |
| </nav> |
| </aside> |
| <article class="flex-column me-lg-4"> |
| <p><code>Txn</code> provides a high level interface to Jena transactions. It is a |
| library over the core functionality - applications do not have to use <code>Txn</code> |
| to use transactions.</p> |
| <p>Features:</p> |
| <ul> |
| <li>Java8 idioms</li> |
| <li>Application exceptions cause transaction aborts.</li> |
| <li>“Transaction continuation” - use any existing active transaction.</li> |
| <li>Autocommit - ensure actions are inside a transaction even if none is active.</li> |
| </ul> |
| <h2 id="transactions">Transactions</h2> |
| <p>The <a href="basic_txn_api.html">basic transactions API</a> provides operations |
| <code>begin</code>, <code>commit</code>, <code>abort</code> and <code>end</code>.</p> |
| <p>A write transaction looks like:</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>dataset<span style="color:#666">.</span><span style="color:#b44">begin</span><span style="color:#666">(</span>ReadWrite<span style="color:#666">.</span><span style="color:#b44">write</span><span style="color:#666">)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#a2f;font-weight:bold">try</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">...</span> write operations <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span> dataset<span style="color:#666">.</span><span style="color:#b44">commit</span><span style="color:#666">()</span> <span style="color:#666">;</span> <span style="color:#080;font-style:italic">// Or abort |
| </span></span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic"></span><span style="color:#666">}</span> <span style="color:#a2f;font-weight:bold">finally</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> dataset<span style="color:#666">.</span><span style="color:#b44">end</span><span style="color:#666">()</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">}</span> |
| </span></span></code></pre></div><p>This can be simplified by wrapping application code, contained in a Java lambda |
| expression or a Java Runnable object, and calling a method of the dataset or |
| other transactional object. This wil apply the correct entry and exit code for |
| a transaction, eliminating coding errors.</p> |
| <p>This is also available via transactional objects such as <code>Dataset</code>.</p> |
| <p>The pattern is:</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span>dataset<span style="color:#666">.</span><span style="color:#b44">executeRead</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">.</span> <span style="color:#666">.</span> <span style="color:#666">.</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>and</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>dataset<span style="color:#666">.</span><span style="color:#b44">executeWrite</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">.</span> <span style="color:#666">.</span> <span style="color:#666">.</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>The form is:</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Txn<span style="color:#666">.</span><span style="color:#b44">executeRead</span><span style="color:#666">(</span>ds<span style="color:#666">,</span> <span style="color:#666">()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">.</span> <span style="color:#666">.</span> <span style="color:#666">.</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>and</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Txn<span style="color:#666">.</span><span style="color:#b44">executeWrite</span><span style="color:#666">(</span>ds<span style="color:#666">,</span> <span style="color:#666">()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">.</span> <span style="color:#666">.</span> <span style="color:#666">.</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>is also available (<code>Txn</code> is the implementation of this machinery). Using Txn is |
| this way is necessary for Jena3.</p> |
| <h2 id="usage">Usage</h2> |
| <p>This first example shows how to write a SPARQL query .</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>Query query <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>dataset<span style="color:#666">.</span><span style="color:#b44">executeRead</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">try</span><span style="color:#666">(</span>QueryExecution qExec <span style="color:#666">=</span> QueryExecutionFactory<span style="color:#666">.</span><span style="color:#b44">create</span><span style="color:#666">(</span>query<span style="color:#666">,</span> dataset<span style="color:#666">))</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> ResultSetFormatter<span style="color:#666">.</span><span style="color:#b44">out</span><span style="color:#666">(</span>qExec<span style="color:#666">.</span><span style="color:#b44">execSelect</span><span style="color:#666">())</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">}</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>Here, a <code>try-with-resources</code> ensures correct handling of the |
| <code>QueryExecution</code> inside a read transaction.</p> |
| <p>Writing to a file is a read-action (it does not update the RDF data, the |
| writer needs to read the dataset or model):</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>dataset<span style="color:#666">.</span><span style="color:#b44">executeRead</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> RDFDataMgr<span style="color:#666">.</span><span style="color:#b44">write</span><span style="color:#666">(</span>System<span style="color:#666">.</span><span style="color:#b44">out</span><span style="color:#666">,</span> dataset<span style="color:#666">,</span> Lang<span style="color:#666">.</span><span style="color:#b44">TRIG</span><span style="color:#666">)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>whereas reading data into an RDF dataset needs to be a write transaction |
| (the dataset or model is changed).</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>dataset<span style="color:#666">.</span><span style="color:#b44">executeWrite</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> RDFDataMgr<span style="color:#666">.</span><span style="color:#b44">read</span><span style="color:#666">(</span><span style="color:#b44">"data.ttl"</span><span style="color:#666">)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>Applications are not limited to a single operation inside a transaction. It |
| can involve multiple applications read operations, such as making several |
| queries:</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>Query query1 <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>Query query2 <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>dataset<span style="color:#666">.</span><span style="color:#b44">executeRead</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">try</span><span style="color:#666">(</span>QueryExecution qExec1 <span style="color:#666">=</span> QueryExecutionFactory<span style="color:#666">.</span><span style="color:#b44">create</span><span style="color:#666">(</span>query1<span style="color:#666">,</span> dataset<span style="color:#666">))</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">}</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">try</span><span style="color:#666">(</span>QueryExecution qExec2 <span style="color:#666">=</span> QueryExecutionFactory<span style="color:#666">.</span><span style="color:#b44">create</span><span style="color:#666">(</span>query2<span style="color:#666">,</span> dataset<span style="color:#666">))</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">}</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span></code></pre></div><p>A <code>calculateRead</code> block can return a result but only with the condition |
| that what is returned does not touch the data again unless it uses a new |
| transaction.</p> |
| <p>This includes returning a result set or returning a model from a dataset.</p> |
| <p><code>ResultSets</code> by default stream - each time <code>hasNext</code> or <code>next</code> is |
| called, new data might be read from the RDF dataset. A copy of the |
| results needs to be taken:</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>Query query <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>List<span style="color:#666"><</span>String<span style="color:#666">></span> results <span style="color:#666">=</span> dataset<span style="color:#666">.</span><span style="color:#b44">calculateRead</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> List<span style="color:#666"><</span>String<span style="color:#666">></span> accumulator <span style="color:#666">=</span> <span style="color:#a2f;font-weight:bold">new</span> ArrayList<span style="color:#666"><>()</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">try</span><span style="color:#666">(</span>QueryExecution qExec <span style="color:#666">=</span> QueryExecutionFactory<span style="color:#666">.</span><span style="color:#b44">create</span><span style="color:#666">(</span>query<span style="color:#666">,</span> dataset<span style="color:#666">))</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> qExec<span style="color:#666">.</span><span style="color:#b44">execSelect</span><span style="color:#666">().</span><span style="color:#b44">forEachRemaining</span><span style="color:#666">((</span>row<span style="color:#666">)->{</span> |
| </span></span><span style="display:flex;"><span> String strThisRow <span style="color:#666">=</span> row<span style="color:#666">.</span><span style="color:#b44">getLiteral</span><span style="color:#666">(</span><span style="color:#b44">"variable"</span><span style="color:#666">).</span><span style="color:#b44">getLexicalForm</span><span style="color:#666">()</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> accumulator<span style="color:#666">.</span><span style="color:#b44">add</span><span style="color:#666">(</span>strThisRow<span style="color:#666">)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">}</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">return</span> accumulator <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic">// use "results" |
| </span></span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic"></span> |
| </span></span><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>Query query <span style="color:#666">=</span> <span style="color:#666">...</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span>ResultSet List<span style="color:#666"><</span>String<span style="color:#666">></span> resultSet <span style="color:#666">=</span> dataset<span style="color:#666">.</span><span style="color:#b44">calculateRead</span><span style="color:#666">(()-></span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> List<span style="color:#666"><</span>String<span style="color:#666">></span> accumulator <span style="color:#666">=</span> <span style="color:#a2f;font-weight:bold">new</span> ArrayList<span style="color:#666"><>()</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">try</span><span style="color:#666">(</span>QueryExecution qExec <span style="color:#666">=</span> QueryExecutionFactory<span style="color:#666">.</span><span style="color:#b44">create</span><span style="color:#666">(</span>query<span style="color:#666">,</span> dataset<span style="color:#666">))</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">return</span> ResultSetFactory<span style="color:#666">.</span><span style="color:#b44">copyResults</span><span style="color:#666">(</span>qExec<span style="color:#666">.</span><span style="color:#b44">execSelect</span><span style="color:#666">())</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">}</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">})</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic">// use "resultSet" |
| </span></span></span></code></pre></div><p>The functions <code>execute</code> and <code>calculate</code> start <code>READ_PROMOTE</code> |
| transactions which start in “read” mode but convert to “write” mode if |
| needed. For details of transaction promotion see the |
| <a href="transactions_api.html#types-modes-promotion">section in the transaction API documentation</a>.</p> |
| <h2 id="working-with-rdf-models">Working with RDF Models</h2> |
| <p>The unit of transaction is the dataset. Model in datasets are just views of that dataset. |
| Model should not be passed out of a transaction because they are still attached to the |
| dataset.</p> |
| <h2 id="autocommit-and-transaction-continuation">Autocommit and Transaction continuation</h2> |
| <p>If there is a transaction already started for the thread, then |
| <code>execute...</code> or <code>calculate...</code> will be performed as part of |
| the transaction and that transaction is not terminated. If there is not transaction already started, |
| a transaction is wrapped around the <code>execute...</code> or <code>calculate...</code> action.</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>Dataset dataset <span style="color:#666">=</span> <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic">// Main transaction. |
| </span></span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic"></span>dataset<span style="color:#666">.</span><span style="color:#b44">begin</span><span style="color:#666">(</span>ReadWrite<span style="color:#666">.</span><span style="color:#b44">WRITE</span><span style="color:#666">)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#a2f;font-weight:bold">try</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#080;font-style:italic">// Part of the transaction above. |
| </span></span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic"></span> dataset<span style="color:#666">.</span><span style="color:#b44">executeRead</span><span style="color:#666">(()</span> <span style="color:#666">-></span> <span style="color:#666">...)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#080;font-style:italic">// Part of the transaction above - no commit/abort |
| </span></span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic"></span> dataset<span style="color:#666">.</span><span style="color:#b44">executeWrite</span><span style="color:#666">(()</span> <span style="color:#666">-></span> <span style="color:#666">...)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> |
| </span></span><span style="display:flex;"><span> <span style="color:#080;font-style:italic">// Outer transaction |
| </span></span></span><span style="display:flex;"><span><span style="color:#080;font-style:italic"></span> dataset<span style="color:#666">.</span><span style="color:#b44">commit</span><span style="color:#666">()</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">}</span> <span style="color:#a2f;font-weight:bold">finally</span> <span style="color:#666">{</span> dataset<span style="color:#666">.</span><span style="color:#b44">end</span><span style="color:#666">()</span> <span style="color:#666">;</span> <span style="color:#666">}</span> |
| </span></span></code></pre></div><h2 id="design">Design</h2> |
| <p><code>Txn</code> uses Java <code>Runnable</code> for the application code, passed into control code |
| that wraps the transaction operations around the application code. This results |
| in application code automatically applied transaction begin/commit/end as needed.</p> |
| <p>A bare read transaction requires the following code structure (no exception handling):</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span>txn<span style="color:#666">.</span><span style="color:#b44">begin</span><span style="color:#666">(</span>ReadWrite<span style="color:#666">.</span><span style="color:#b44">READ</span><span style="color:#666">)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#a2f;font-weight:bold">try</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#666">...</span> application code <span style="color:#666">...</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">}</span> <span style="color:#a2f;font-weight:bold">finally</span> <span style="color:#666">{</span> txn<span style="color:#666">.</span><span style="color:#b44">end</span><span style="color:#666">()</span> <span style="color:#666">;</span> <span style="color:#666">}</span> |
| </span></span></code></pre></div><p>while a write transaction requires either a <code>commit</code> or an <code>abort</code> |
| at the end of the application code as well.</p> |
| <p>Without the transaction continuation code (simplified, the <code>Txn</code> code |
| for a read transaction takes the form:</p> |
| <div class="highlight"><pre tabindex="0" style="background-color:#f8f8f8;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-java" data-lang="java"><span style="display:flex;"><span><span style="color:#a2f;font-weight:bold">public</span> <span style="color:#a2f;font-weight:bold">static</span> <span style="color:#666"><</span>T <span style="color:#a2f;font-weight:bold">extends</span> Transactional<span style="color:#666">></span> <span style="color:#0b0;font-weight:bold">void</span> <span style="color:#00a000">executeRead</span><span style="color:#666">(</span>T txn<span style="color:#666">,</span> Runnable r<span style="color:#666">)</span> <span style="color:#666">{</span> |
| </span></span><span style="display:flex;"><span> txn<span style="color:#666">.</span><span style="color:#b44">begin</span><span style="color:#666">(</span>ReadWrite<span style="color:#666">.</span><span style="color:#b44">READ</span><span style="color:#666">)</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">try</span> <span style="color:#666">{</span> r<span style="color:#666">.</span><span style="color:#b44">run</span><span style="color:#666">()</span> <span style="color:#666">;</span> <span style="color:#666">}</span> |
| </span></span><span style="display:flex;"><span> <span style="color:#a2f;font-weight:bold">catch</span> <span style="color:#666">(</span>Throwable th<span style="color:#666">)</span> <span style="color:#666">{</span> txn<span style="color:#666">.</span><span style="color:#b44">end</span><span style="color:#666">()</span> <span style="color:#666">;</span> <span style="color:#a2f;font-weight:bold">throw</span> th <span style="color:#666">;</span> <span style="color:#666">}</span> |
| </span></span><span style="display:flex;"><span> txn<span style="color:#666">.</span><span style="color:#b44">end</span><span style="color:#666">()</span> <span style="color:#666">;</span> |
| </span></span><span style="display:flex;"><span><span style="color:#666">}</span> |
| </span></span></code></pre></div><p>See <a href="https://github.com/apache/jena/blob/main/jena-arq/src/main/java/org/apache/jena/query/Txn.java"><code>Txn.java</code></a> for full details.</p> |
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