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| <a class="edit-on-gh" href="https://github.com/apache/struts-site/edit/master/source/getting-started/processing-forms.md" title="Edit this page on GitHub">Edit on GitHub</a> |
| |
| <a href="index.html" title="back to Getting started"><< back to Getting started</a> |
| |
| <h1 class="no_toc" id="processing-forms">Processing Forms</h1> |
| |
| <ul id="markdown-toc"> |
| <li><a href="#introduction" id="markdown-toc-introduction">Introduction</a></li> |
| <li><a href="#forms-and-a-java-model-class" id="markdown-toc-forms-and-a-java-model-class">Forms and a Java model class</a></li> |
| <li><a href="#form-structure" id="markdown-toc-form-structure">Form structure</a></li> |
| <li><a href="#creating-the-action-class-to-handle-the-form-submission" id="markdown-toc-creating-the-action-class-to-handle-the-form-submission">Creating the Action class to handle the form submission</a></li> |
| <li><a href="#adding-the-view-for-the-result" id="markdown-toc-adding-the-view-for-the-result">Adding the view for the result</a></li> |
| <li><a href="#create-action-mapping-in-strutsxml" id="markdown-toc-create-action-mapping-in-strutsxml">Create action mapping in struts.xml</a></li> |
| <li><a href="#create-a-link-to-registerjsp" id="markdown-toc-create-a-link-to-registerjsp">Create a link to register.jsp</a></li> |
| </ul> |
| |
| <p>This tutorial assumes you’ve completed the <a href="coding-actions">Coding Struts 2 Actions</a> tutorial and have a working |
| <strong>coding-actions</strong> project. The example code for this tutorial, <strong>form-processing</strong>, is available for checkout from |
| the Struts 2 GitHub repository <a href="https://github.com/apache/struts-examples">struts-examples</a>.</p> |
| |
| <h2 id="introduction">Introduction</h2> |
| |
| <p>In this tutorial we’ll explore using Struts 2 to do more involved processing of a form submission. We’ll cover how to |
| use a Java model class to store the form input and how to create the Struts 2 form to match up with that model class.</p> |
| |
| <p>The code provided in this tutorial may be added to the <a href="coding-actions">Coding Struts 2 Actions</a> example or you |
| can download this complete example from the github respository - <a href="https://github.com/apache/struts-examples">https://github.com/apache/struts-examples</a>.</p> |
| |
| <p>The <a href="http://struts.apache.org/mail">Struts 2 user mailing list</a> is an excellent place to get help. If you are |
| having a problem getting the tutorial example applications to work search the Struts 2 mailing list. If you don’t find |
| an answer to your problem, post a question on the mailing list.</p> |
| |
| <h2 id="forms-and-a-java-model-class">Forms and a Java model class</h2> |
| |
| <p>For this tutorial let’s say we need to provide a form that a user may submit to register for a prize drawing. Our |
| business rules state the user must provide his/her first name, last name, email address, and age.</p> |
| |
| <p>To encapsulate this data, we’ll use a simple Java class that follows the basic Java Bean specifications (public set/get |
| methods for each instance field). If you’re following along add this class to the package <code class="language-plaintext highlighter-rouge">org.apache.struts.register.model</code> |
| in the <a href="coding-actions">Coding Struts 2 Actions</a> example.</p> |
| |
| <p><strong>Person.java</strong></p> |
| |
| <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">public</span> <span class="kd">class</span> <span class="nc">Person</span> <span class="o">{</span> |
| <span class="kd">private</span> <span class="nc">String</span> <span class="n">firstName</span><span class="o">;</span> |
| <span class="kd">private</span> <span class="nc">String</span> <span class="n">lastName</span><span class="o">;</span> |
| <span class="kd">private</span> <span class="nc">String</span> <span class="n">email</span><span class="o">;</span> |
| <span class="kd">private</span> <span class="kt">int</span> <span class="n">age</span><span class="o">;</span> |
| |
| <span class="kd">public</span> <span class="nc">String</span> <span class="nf">getFirstName</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="n">firstName</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setFirstName</span><span class="o">(</span><span class="nc">String</span> <span class="n">firstName</span><span class="o">)</span> <span class="o">{</span> |
| <span class="k">this</span><span class="o">.</span><span class="na">firstName</span> <span class="o">=</span> <span class="n">firstName</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="nc">String</span> <span class="nf">getLastName</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="n">lastName</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setLastName</span><span class="o">(</span><span class="nc">String</span> <span class="n">lastName</span><span class="o">)</span> <span class="o">{</span> |
| <span class="k">this</span><span class="o">.</span><span class="na">lastName</span> <span class="o">=</span> <span class="n">lastName</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="nc">String</span> <span class="nf">getEmail</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="n">email</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setEmail</span><span class="o">(</span><span class="nc">String</span> <span class="n">email</span><span class="o">)</span> <span class="o">{</span> |
| <span class="k">this</span><span class="o">.</span><span class="na">email</span> <span class="o">=</span> <span class="n">email</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="kt">int</span> <span class="nf">getAge</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="n">age</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setAge</span><span class="o">(</span><span class="kt">int</span> <span class="n">age</span><span class="o">)</span> <span class="o">{</span> |
| <span class="k">this</span><span class="o">.</span><span class="na">age</span> <span class="o">=</span> <span class="n">age</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="nc">String</span> <span class="nf">toString</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="s">"First Name: "</span> <span class="o">+</span> <span class="n">getFirstName</span><span class="o">()</span> <span class="o">+</span> <span class="s">" Last Name: "</span> <span class="o">+</span> <span class="n">getLastName</span><span class="o">()</span> <span class="o">+</span> |
| <span class="s">" Email: "</span> <span class="o">+</span> <span class="n">getEmail</span><span class="o">()</span> <span class="o">+</span> <span class="s">" Age: "</span> <span class="o">+</span> <span class="n">getAge</span><span class="o">()</span> <span class="o">;</span> |
| <span class="o">}</span> |
| <span class="o">}</span> |
| </code></pre></div></div> |
| |
| <p>Note a few points about the above class. There is a public set/get method for each instance field. The age attribute |
| is of type integer. We’ve defined a public <code class="language-plaintext highlighter-rouge">toString</code> method that returns a String representing the state of the object. |
| Since we haven’t specified a constructor, Java will provide a default constructor that will set all instance fields to |
| their null values.</p> |
| |
| <h2 id="form-structure">Form structure</h2> |
| |
| <p>To collect the above information we’ll use a Struts 2 form. When creating this form the key concept we need to employ |
| is to tie each form field to a specific instance field of an object of type Person. Let’s look over the form first and |
| then discuss some key points. Create a view page named <code class="language-plaintext highlighter-rouge">register.jsp</code> (in <code class="language-plaintext highlighter-rouge">src/main/webapp</code>)</p> |
| |
| <p><strong>register.jsp</strong></p> |
| |
| <div class="language-jsp highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt"><%@ taglib </span><span class="na">prefix=</span><span class="s">"s"</span><span class="na"> uri=</span><span class="s">"/struts-tags"</span> <span class="nt">%></span> |
| <span class="nt"><%@ page </span><span class="na">language=</span><span class="s">"java"</span><span class="na"> contentType=</span><span class="s">"text/html; charset=UTF-8"</span><span class="na"> pageEncoding=</span><span class="s">"UTF-8"</span><span class="nt">%></span> |
| <span class="cp"><!DOCTYPE html></span> |
| <span class="nt"><html></span> |
| <span class="nt"><head></span> |
| <span class="nt"><meta</span> <span class="na">http-equiv=</span><span class="s">"Content-Type"</span> <span class="na">content=</span><span class="s">"text/html; charset=UTF-8"</span> <span class="nt">/></span> |
| <span class="nt"><title></span>Register<span class="nt"></title></span> |
| <span class="nt"></head></span> |
| <span class="nt"><body></span> |
| <span class="nt"><h3></span>Register for a prize by completing this form.<span class="nt"></h3></span> |
| |
| <span class="nt"><s:form </span><span class="na">action=</span><span class="s">"register"</span><span class="nt">></span> |
| <span class="nt"><s:textfield </span><span class="na">name=</span><span class="s">"personBean.firstName"</span><span class="na"> label=</span><span class="s">"First name"</span> <span class="nt">/></span> |
| <span class="nt"><s:textfield </span><span class="na">name=</span><span class="s">"personBean.lastName"</span><span class="na"> label=</span><span class="s">"Last name"</span> <span class="nt">/></span> |
| <span class="nt"><s:textfield </span><span class="na">name=</span><span class="s">"personBean.email"</span><span class="na"> label =</span><span class="s">"Email"</span><span class="nt">/></span> |
| <span class="nt"><s:textfield </span><span class="na">name=</span><span class="s">"personBean.age"</span><span class="na"> label=</span><span class="s">"Age"</span> <span class="nt">/></span> |
| <span class="nt"><s:submit/></span> |
| <span class="nt"></s:form></span> |
| <span class="nt"></body></span> |
| <span class="nt"></html></span> |
| </code></pre></div></div> |
| |
| <p>Since we are using Struts 2 tags, at the top of the page we need the Struts tag library declaration.</p> |
| |
| <p>The Struts 2 form will submit to an action named register. We’ll need to define that action in our <code class="language-plaintext highlighter-rouge">struts.xml</code> file.</p> |
| |
| <p>Note the four Struts 2 textfield tags. Each tag has a name value that includes an attribute of the <code class="language-plaintext highlighter-rouge">Person</code> class |
| (e.g. <code class="language-plaintext highlighter-rouge">firstName</code>). The name attribute’s value also has a reference to an object called <code class="language-plaintext highlighter-rouge">personBean</code>. This object is |
| of type <code class="language-plaintext highlighter-rouge">Person</code>. When we create the Action class that handles this form submission, we’ll have to specify that object |
| in that Action class and annotate it (see below).</p> |
| |
| <p>The complete name value, <code class="language-plaintext highlighter-rouge">personBean.firstName</code>, instructs Struts 2 to use the input value for that textfield as |
| the argument to the personBean object’s <code class="language-plaintext highlighter-rouge">setFirstName</code> method. So if the user types “Bruce” in the textfield that has |
| the label “First name”, the personBean’s <code class="language-plaintext highlighter-rouge">firstName</code> instance field will have a value of “Bruce”.</p> |
| |
| <p>Note that we have a Struts 2 textfield for each instance field of the class Person. Remember that Person class’s age |
| attribute is of type integer. All form field input values are Strings. Struts 2 will automatically convert the String |
| value (“25”) the user entered for the age form field to 25 when calling the <code class="language-plaintext highlighter-rouge">setAge</code> method of object <code class="language-plaintext highlighter-rouge">personBean</code>.</p> |
| |
| <h2 id="creating-the-action-class-to-handle-the-form-submission">Creating the Action class to handle the form submission</h2> |
| |
| <p>When the user clicks on the submit button of the above form, the action “register” and the form data will be sent to |
| the Struts 2 framework. We need an Action class to process this form. If you recall from the tutorial |
| <a href="coding-actions">Coding Struts 2 Actions</a> our Action class should extend the Struts 2 ActionSupport class.</p> |
| |
| <p>Here is the Action class used for this example. Place it in package org.apache.struts.register.action.</p> |
| |
| <p><strong>Register.java Struts 2 Action Class</strong></p> |
| |
| <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kn">package</span> <span class="nn">org.apache.struts.register.action</span><span class="o">;</span> |
| |
| <span class="kn">import</span> <span class="nn">com.opensymphony.xwork2.ActionSupport</span><span class="o">;</span> |
| <span class="kn">import</span> <span class="nn">org.apache.struts.register.model.Person</span><span class="o">;</span> |
| |
| <span class="kd">public</span> <span class="kd">class</span> <span class="nc">Register</span> <span class="kd">extends</span> <span class="nc">ActionSupport</span> <span class="o">{</span> |
| |
| <span class="kd">private</span> <span class="kd">static</span> <span class="kd">final</span> <span class="kt">long</span> <span class="n">serialVersionUID</span> <span class="o">=</span> <span class="mi">1L</span><span class="o">;</span> |
| |
| <span class="kd">private</span> <span class="nc">Person</span> <span class="n">personBean</span><span class="o">;</span> |
| |
| |
| <span class="kd">public</span> <span class="nc">String</span> <span class="nf">execute</span><span class="o">()</span> <span class="kd">throws</span> <span class="nc">Exception</span> <span class="o">{</span> |
| <span class="c1">//call Service class to store personBean's state in database</span> |
| |
| <span class="k">return</span> <span class="no">SUCCESS</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="nd">@StrutsParameter</span><span class="o">(</span><span class="n">depth</span> <span class="o">=</span> <span class="mi">1</span><span class="o">)</span> |
| <span class="kd">public</span> <span class="nc">Person</span> <span class="nf">getPersonBean</span><span class="o">()</span> <span class="o">{</span> |
| <span class="k">return</span> <span class="n">personBean</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="kd">public</span> <span class="kt">void</span> <span class="nf">setPersonBean</span><span class="o">(</span><span class="nc">Person</span> <span class="n">person</span><span class="o">)</span> <span class="o">{</span> |
| <span class="n">personBean</span> <span class="o">=</span> <span class="n">person</span><span class="o">;</span> |
| <span class="o">}</span> |
| |
| <span class="o">}</span> |
| </code></pre></div></div> |
| |
| <p>In the <code class="language-plaintext highlighter-rouge">Register</code> class, note that we’ve declared an attribute named <code class="language-plaintext highlighter-rouge">personBean</code> of type <code class="language-plaintext highlighter-rouge">Person</code>, there are public |
| getter and setter methods for this object, and the getter is annotated with <code class="language-plaintext highlighter-rouge">@StrutsParameter(depth = 1)</code>.</p> |
| |
| <p>In the previous <a href="coding-actions">Coding Struts 2 Actions</a> tutorial, we annotated the username <strong>setter</strong>, which took a |
| simple String as its parameter type, with <code class="language-plaintext highlighter-rouge">@StrutsParameter</code>. In this example, we are using a “Bean” object (sometimes |
| referred to as a DTO or model object) to encapsulate the form data. When we choose to use a DTO instead of a primitive, |
| String, or other TypeConverter supported object, we must annotate the <strong>getter</strong> method instead, and also assign a depth |
| corresponding to how deep the DTO graph is. In this case, the <code class="language-plaintext highlighter-rouge">Person</code> object does not have any further DTOs or |
| collections within it, so a depth of 1 will suffice.</p> |
| |
| <p>For more information on these annotations and their security implications, please refer |
| to <a href="../security/index#defining-and-annotating-your-action-parameters">Security</a>.</p> |
| |
| <p>The <code class="language-plaintext highlighter-rouge">Register</code> class also overrides the <code class="language-plaintext highlighter-rouge">execute</code> method. The <code class="language-plaintext highlighter-rouge">execute</code> method is the one we will specify in the |
| <code class="language-plaintext highlighter-rouge">struts.xml</code> to be called in response to the register action. In this example, the <code class="language-plaintext highlighter-rouge">execute</code> method just returns |
| the String constant <code class="language-plaintext highlighter-rouge">SUCCESS</code> (inherited from the <code class="language-plaintext highlighter-rouge">ActionSupport</code> class). But in a real application, within the <code class="language-plaintext highlighter-rouge">execute</code> |
| method we would call upon other classes (Service objects) to perform the business processing of the form, such as storing |
| the user’s input into a data repository.</p> |
| |
| <p>The <code class="language-plaintext highlighter-rouge">personBean</code> getter of return type <code class="language-plaintext highlighter-rouge">Person</code> declared in the Register Action class matches the <code class="language-plaintext highlighter-rouge">personBean</code> name we |
| used in the form’s textfields. When the form is submitted, the Struts 2 framework will inspect the Action class and look |
| for a getter for <code class="language-plaintext highlighter-rouge">personBean</code>. If it returns <code class="language-plaintext highlighter-rouge">null</code> and a matching setter exists, it will create that object using the |
| <code class="language-plaintext highlighter-rouge">Person</code> class’s default constructor and set it using the setter. Note that the setter can be omitted if your Action |
| initialises the field on construction. Then for each form field that has a name value of personBean.someAttribute |
| (e.g <code class="language-plaintext highlighter-rouge">personBean.firstName</code>) it will call the personBean’s public set method for that attribute and pass it the form |
| field’s value (the user input). This all happens before the execute method occurs.</p> |
| |
| <p>When Struts 2 runs the <code class="language-plaintext highlighter-rouge">execute</code> method of class <code class="language-plaintext highlighter-rouge">Register</code>, the <code class="language-plaintext highlighter-rouge">personBean</code> object in class <code class="language-plaintext highlighter-rouge">Register</code> now has values |
| for its instance fields that are equal to the values the user entered into the corresponding form fields.</p> |
| |
| <p>By using a Java model class to encapsulate the data provided by the form we don’t have to have a separate attribute |
| (with public set/get methods) in the Action class (Register) for each form field.</p> |
| |
| <h2 id="adding-the-view-for-the-result">Adding the view for the result</h2> |
| |
| <p>When <code class="language-plaintext highlighter-rouge">SUCCESS</code> is returned by the <code class="language-plaintext highlighter-rouge">execute</code> method we want to display a simple thank you page that shows the user’s |
| registration. Add the <code class="language-plaintext highlighter-rouge">thankyou.jsp</code> below to <code class="language-plaintext highlighter-rouge">src/main/webapp</code>.</p> |
| |
| <p><strong>thankyou.jsp</strong></p> |
| |
| <div class="language-jsp highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt"><%@ taglib </span><span class="na">prefix=</span><span class="s">"s"</span><span class="na"> uri=</span><span class="s">"/struts-tags"</span> <span class="nt">%></span> |
| <span class="nt"><%@ page </span><span class="na">language=</span><span class="s">"java"</span><span class="na"> contentType=</span><span class="s">"text/html; charset=UTF-8"</span><span class="na"> pageEncoding=</span><span class="s">"UTF-8"</span><span class="nt">%></span> |
| <span class="cp"><!DOCTYPE html></span> |
| <span class="nt"><html></span> |
| <span class="nt"><head></span> |
| <span class="nt"><meta</span> <span class="na">http-equiv=</span><span class="s">"Content-Type"</span> <span class="na">content=</span><span class="s">"text/html; charset=UTF-8"</span> <span class="nt">/></span> |
| <span class="nt"><title></span>Registration Successful<span class="nt"></title></span> |
| <span class="nt"></head></span> |
| <span class="nt"><body></span> |
| <span class="nt"><h3></span>Thank you for registering for a prize.<span class="nt"></h3></span> |
| |
| <span class="nt"><p></span>Your registration information: <span class="nt"><s:property </span><span class="na">value=</span><span class="s">"personBean"</span> <span class="nt">/></span> <span class="nt"></p></span> |
| |
| <span class="nt"><p><a</span> <span class="na">href=</span><span class="s">"</span><span class="nt"><s:url </span><span class="na">action=</span><span class="s">'index' </span><span class="nt">/></span><span class="s">"</span> <span class="nt">></span>Return to home page<span class="nt"></a></span>.<span class="nt"></p></span> |
| <span class="nt"></body></span> |
| <span class="nt"></html></span> |
| </code></pre></div></div> |
| |
| <p>If you don’t recall how the Struts 2 property and url tags work consult the <a href="using-tags">Using Struts 2 Tags</a> tutorial.</p> |
| |
| <h2 id="create-action-mapping-in-strutsxml">Create action mapping in struts.xml</h2> |
| |
| <p>To specify the relationship between the form submission page, the Struts 2 Action class, and the success view page |
| we need to add an action node to <code class="language-plaintext highlighter-rouge">struts.xml</code>. Add this action node to <code class="language-plaintext highlighter-rouge">struts.xml</code> (<code class="language-plaintext highlighter-rouge">src/main/resources</code>) after |
| the hello action and before the closing package node.</p> |
| |
| <p><strong>action node for struts.xml</strong></p> |
| |
| <div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt"><action</span> <span class="na">name=</span><span class="s">"register"</span> <span class="na">class=</span><span class="s">"org.apache.struts.register.action.Register"</span> <span class="na">method=</span><span class="s">"execute"</span><span class="nt">></span> |
| <span class="nt"><result</span> <span class="na">name=</span><span class="s">"success"</span><span class="nt">></span>/thankyou.jsp<span class="nt"></result></span> |
| <span class="nt"></action></span> |
| </code></pre></div></div> |
| |
| <p>The above action tells Struts 2 that when the register action is provided to call method <code class="language-plaintext highlighter-rouge">execute</code> of class <code class="language-plaintext highlighter-rouge">Register</code>. |
| If that method returns result “success” return to the browser the <code class="language-plaintext highlighter-rouge">thankyou.jsp</code>.</p> |
| |
| <p>Note that we don’t need to tell Struts 2 anything about processing the form. The transfer of the form field input values |
| to the <code class="language-plaintext highlighter-rouge">personBean</code> object will happen automatically provided we’ve followed the convention of naming our form fields |
| to match personBean.attributeName (e.g. <code class="language-plaintext highlighter-rouge">personBean.lastName</code>).</p> |
| |
| <h2 id="create-a-link-to-registerjsp">Create a link to register.jsp</h2> |
| |
| <p>So that the user can find the registration page, add this link to index.jsp</p> |
| |
| <p><strong>Link to register.jsp</strong></p> |
| |
| <div class="language-html highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt"><p><a</span> <span class="na">href=</span><span class="s">"register.jsp"</span><span class="nt">></span>Please register<span class="nt"></a></span> for our prize drawing.<span class="nt"></p></span> |
| </code></pre></div></div> |
| |
| <p><strong>Run The Example</strong></p> |
| |
| <p>If everything is correct, you should be able to run the application (using <code class="language-plaintext highlighter-rouge">mvn jetty:run</code>), and open this URL in your |
| web browser: |
| <a href="http://localhost:8080/form-processing/index.action">http://localhost:8080/form-processing/index.action</a>. On that page |
| should be a link to register. |
| Click on that link and you should see the <code class="language-plaintext highlighter-rouge">register.jsp</code> page.</p> |
| |
| <p><img src="attachments/att14974999_registerjsp.png" alt="registerjsp.png" /></p> |
| |
| <p>Fill out the form and click the submit button. You should then see the <code class="language-plaintext highlighter-rouge">thankyou.jsp</code> page.</p> |
| |
| <p><img src="attachments/att14975000_thanyoujsp.png" alt="thanyoujsp.png" /></p> |
| |
| <table> |
| <tbody> |
| <tr> |
| <td>Return to <a href="coding-actions">Coding Struts 2 Actions</a></td> |
| <td>or</td> |
| <td>onward to <a href="form-validation">Form validation</a></td> |
| </tr> |
| </tbody> |
| </table> |
| |
| </section> |
| </article> |
| |
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