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     <h1 class="no_toc" id="annotations">Annotations</h1>

 <ul id="markdown-toc">
   <li><a href="#action-annotations" id="markdown-toc-action-annotations">Action Annotations</a></li>
   <li><a href="#workflow-annotations" id="markdown-toc-workflow-annotations">Workflow Annotations</a></li>
   <li><a href="#interceptor-annotations" id="markdown-toc-interceptor-annotations">Interceptor Annotations</a></li>
   <li><a href="#validation-annotations" id="markdown-toc-validation-annotations">Validation Annotations</a>    <ul>
       <li><a href="#resources" id="markdown-toc-resources">Resources</a></li>
     </ul>
   </li>
   <li><a href="#type-conversion-annotations" id="markdown-toc-type-conversion-annotations">Type Conversion Annotations</a></li>
   <li><a href="#tiles-annotations" id="markdown-toc-tiles-annotations">Tiles Annotations</a></li>
 </ul>

 <p>In many places, applications can use Java 5 annotations as an alternative to XML and Java properties configuration.
 This page serves as a reference for all annotations across the framework.</p>

 <h2 id="action-annotations">Action Annotations</h2>

 <p>Since Struts 2.1, these annotations are provided by the <a href="../plugins/convention/">Convention Plugin</a>. Codebehind and Zero Config
 plugins are deprecated from Struts 2.1 on.</p>

 <p>Action annotations are available when the framework scans the classpath for Action classes, rather than specifying
 individual mappings through XML configuration. See the <a href="../plugins/convention/">Convention Plugin</a> page for information
 on how to set up classpath scanning to allow the use of Action annotations.</p>

 <table>
   <thead>
     <tr>
       <th>Annotation</th>
       <th>Description</th>
     </tr>
   </thead>
   <tbody>
     <tr>
       <td><a href="../plugins/convention/#action-annotation">Actions Annotation</a></td>
       <td>Group of <code class="language-plaintext highlighter-rouge">@Action</code> annotations, maps multiple URLs to the same action</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#action-annotation">Action Annotation</a></td>
       <td>Defines the URL of an action</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#interceptorref-annotation">InterceptorRefs Annotation</a></td>
       <td>Group of <code class="language-plaintext highlighter-rouge">@InterceptorRef</code> annotations</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#interceptorref-annotation">InterceptorRef Annotation</a></td>
       <td>Interceptor, or interceptor stack to be applied to at action</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#result-annotation">Results Annotation</a></td>
       <td>Group of <code class="language-plaintext highlighter-rouge">@Result</code> annotations</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#result-annotation">Result Annotation</a></td>
       <td>Defines a result for an action</td>
     </tr>
     <tr>
       <td><a href="namespace-annotation">Namespace Annotation</a></td>
       <td>Set the path of the action URL (used to overwrite the default)</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#resultpath-annotation">ResultPath Annotation</a></td>
       <td>Set where the results are located (used to overwrite the default)</td>
     </tr>
     <tr>
       <td><a href="..//plugins/convention/#parentpackage-annotation">ParentPackage Annotation</a></td>
       <td>Set the parent package of the actions (used to overwrite the default)</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#exceptionmapping-annotation">ExceptionMappings</a></td>
       <td>Group of <code class="language-plaintext highlighter-rouge">@ExceptionMapping</code> annotations</td>
     </tr>
     <tr>
       <td><a href="../plugins/convention/#exceptionmapping-annotation">ExceptionMapping</a></td>
       <td>Defines an exception mapping</td>
     </tr>
   </tbody>
 </table>

 <h2 id="workflow-annotations">Workflow Annotations</h2>

 <table>
   <thead>
     <tr>
       <th>Annotation</th>
       <th>Description</th>
     </tr>
   </thead>
   <tbody>
     <tr>
       <td><a href="input-config-annotation">InputConfig Annotation</a></td>
       <td>Defines what method to execute, or result to be returned if there are validation errors</td>
     </tr>
   </tbody>
 </table>

 <h2 id="interceptor-annotations">Interceptor Annotations</h2>

 <p>To use these annotations, you have to specify the <a href="annotation-workflow-interceptor">AnnotationWorkflowInterceptor</a>
 to your interceptor stack.</p>

 <table>
   <thead>
     <tr>
       <th>Annotation</th>
       <th>Description</th>
     </tr>
   </thead>
   <tbody>
     <tr>
       <td><a href="after-annotation">After Annotation</a></td>
       <td>Marks a action method that needs to be executed after the result.</td>
     </tr>
     <tr>
       <td><a href="before-annotation">Before Annotation</a></td>
       <td>Marks a action method that needs to be executed before the main action method.</td>
     </tr>
     <tr>
       <td><a href="before-result-annotation">BeforeResult Annotation</a></td>
       <td>Marks a action method that needs to be executed before the result.</td>
     </tr>
   </tbody>
 </table>

 <h2 id="validation-annotations">Validation Annotations</h2>

 <p>To use annotation-based validation, annotate the class or interface with <a href="validation-annotation">Validation Annotation</a>.</p>

 <table>
   <thead>
     <tr>
       <th>Annotation</th>
       <th>Description</th>
     </tr>
   </thead>
   <tbody>
     <tr>
       <td><a href="conversion-error-field-validator-annotation">ConversionErrorFieldValidator Annotation</a></td>
       <td>Checks if there are any conversion errors for a field.</td>
     </tr>
     <tr>
       <td><a href="date-range-field-validator-annotation">DateRangeFieldValidator Annotation</a></td>
       <td>Checks that a date field has a value within a specified range.</td>
     </tr>
     <tr>
       <td><a href="double-range-field-validator-annotation">DoubleRangeFieldValidator Annotation</a></td>
       <td>Checks that a double field has a value within a specified range.</td>
     </tr>
     <tr>
       <td><a href="email-validator-annotation">EmailValidator Annotation</a></td>
       <td>Checks that a field is a valid e-mail address.</td>
     </tr>
     <tr>
       <td><a href="expression-validator-annotation">ExpressionValidator Annotation</a></td>
       <td>Validates an expression.</td>
     </tr>
     <tr>
       <td><a href="field-expression-validator-annotation">FieldExpressionValidator Annotation</a></td>
       <td>Uses an OGNL expression to perform its validator.</td>
     </tr>
     <tr>
       <td><a href="int-range-field-validator-annotation">IntRangeFieldValidator Annotation</a></td>
       <td>Checks that a numeric field has a value within a specified range.</td>
     </tr>
     <tr>
       <td><a href="regex-field-validator-annotation">RegexFieldValidator Annotation</a></td>
       <td>Validates a regular expression for a field.</td>
     </tr>
     <tr>
       <td><a href="required-field-validator-annotation">RequiredFieldValidator Annotation</a></td>
       <td>Checks that a field is non-null.</td>
     </tr>
     <tr>
       <td><a href="required-string-validator-annotation">RequiredStringValidator Annotation</a></td>
       <td>Checks that a String field is not empty.</td>
     </tr>
     <tr>
       <td><a href="string-length-field-validator-annotation">StringLengthFieldValidator Annotation</a></td>
       <td>Checks that a String field is of the right length.</td>
     </tr>
     <tr>
       <td><a href="url-validator-annotation">UrlValidator Annotation</a></td>
       <td>Checks that a field is a valid URL.</td>
     </tr>
     <tr>
       <td><a href="validation-annotation">Validation Annotation</a></td>
       <td>Marker annotation for validation at Type level.</td>
     </tr>
     <tr>
       <td><a href="validations-annotation">Validations Annotation</a></td>
       <td>Used to group validation annotations.</td>
     </tr>
     <tr>
       <td><a href="visitor-field-validator-annotation">VisitorFieldValidator Annotation</a></td>
       <td>Invokes the validation for a property’s object type.</td>
     </tr>
     <tr>
       <td><a href="custom-validator-annotation">CustomValidator Annotation</a></td>
       <td>Use this annotation for your custom validator types.</td>
     </tr>
   </tbody>
 </table>

 <h3 id="resources">Resources</h3>

 <ul>
   <li><a href="http://arsenalist.com/2007/05/10/struts-2-validation-using-annotations/">Validation using Annotations</a> (arsenalist)</li>
 </ul>

 <h2 id="type-conversion-annotations">Type Conversion Annotations</h2>

 <p>By default, type conversion for Maps and Collections using generics is directly supported.</p>

 <p>In short, instead of specifying the types found in collections and maps as documented
 in <a href="type-conversion">Type Conversion</a>, <strong>the collection’s generic type is used</strong>. By using annotations,
 an application should be able to avoid using any <code class="language-plaintext highlighter-rouge">ClassName-conversion.properties</code> files.</p>

 <p>To use annotation-based type conversion, annotate the class or interface with the <a href="conversion-annotation">Conversion Annotation</a>.</p>

 <table>
   <thead>
     <tr>
       <th>Annotation</th>
       <th>Description</th>
     </tr>
   </thead>
   <tbody>
     <tr>
       <td><a href="conversion-annotation">Conversion Annotation</a></td>
       <td>Marker annotation for type conversions at Type level.</td>
     </tr>
     <tr>
       <td><a href="create-if-null-annotation">CreateIfNull Annotation</a></td>
       <td>For Collection and Map types: Create the types within the Collection or Map, if null.</td>
     </tr>
     <tr>
       <td><a href="element-annotation">Element Annotation</a></td>
       <td>For Generic types: Specify the element type for Collection types and Map values.</td>
     </tr>
     <tr>
       <td><a href="key-annotation">Key Annotation</a></td>
       <td>For Generic types: Specify the key type for Map keys.</td>
     </tr>
     <tr>
       <td><a href="key-property-annotation">KeyProperty Annotation</a></td>
       <td>For Generic types: Specify the key property name value.</td>
     </tr>
     <tr>
       <td><a href="type-conversion-annotation">TypeConversion Annotation</a></td>
       <td>Used for class and application wide conversion rules.</td>
     </tr>
   </tbody>
 </table>

 <h2 id="tiles-annotations">Tiles Annotations</h2>

 <p>The <a href="../plugins/tiles/">Tiles Plugin</a> provides it’s own set of Annotations. They can be used to keep <code class="language-plaintext highlighter-rouge">tiles.xml</code> short.
 Instead tiles definitions can be created by annotating actions.</p>

 <table>
   <thead>
     <tr>
       <th>Annotation</th>
       <th>Description</th>
     </tr>
   </thead>
   <tbody>
     <tr>
       <td>TilesDefinition</td>
       <td>Represents a <code class="language-plaintext highlighter-rouge">&lt;definition&gt;</code> element in tiles.xml</td>
     </tr>
     <tr>
       <td>TilesDefinitions</td>
       <td>A list of <code class="language-plaintext highlighter-rouge">TilesDefinition</code> Annotations</td>
     </tr>
     <tr>
       <td>TilesPutAttribute</td>
       <td>Represents a <code class="language-plaintext highlighter-rouge">&lt;put-attribute&gt;</code> element in tiles.xml</td>
     </tr>
     <tr>
       <td>TilesPutListAttribute</td>
       <td>Represents a <code class="language-plaintext highlighter-rouge">&lt;put-list-attribute&gt;</code> element in tiles.xml</td>
     </tr>
     <tr>
       <td>TilesAddAttribute</td>
       <td>Represents a <code class="language-plaintext highlighter-rouge">&lt;add-attribute&gt;</code> element in tiles.xml</td>
     </tr>
     <tr>
       <td>TilesAddListAttribute</td>
       <td>Represents a <code class="language-plaintext highlighter-rouge">&lt;add-list-attribute&gt;</code> element in tiles.xml</td>
     </tr>
   </tbody>
 </table>

 <p> </p>

   </section>
 </article>


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	<article class="container">
	<section class="col-md-12">
	<a class="edit-on-gh" href="https://github.com/apache/struts-site/edit/master/source/core-developers/annotations.md" title="Edit this page on GitHub">Edit on GitHub</a>

	<a href="index.html" title="back to Core Developers Guide"><< back to Core Developers Guide</a>

	<h1 class="no_toc" id="annotations">Annotations</h1>

	<ul id="markdown-toc">
	<li><a href="#action-annotations" id="markdown-toc-action-annotations">Action Annotations</a></li>
	<li><a href="#workflow-annotations" id="markdown-toc-workflow-annotations">Workflow Annotations</a></li>
	<li><a href="#interceptor-annotations" id="markdown-toc-interceptor-annotations">Interceptor Annotations</a></li>
	<li><a href="#validation-annotations" id="markdown-toc-validation-annotations">Validation Annotations</a> <ul>
	<li><a href="#resources" id="markdown-toc-resources">Resources</a></li>
	</ul>
	</li>
	<li><a href="#type-conversion-annotations" id="markdown-toc-type-conversion-annotations">Type Conversion Annotations</a></li>
	<li><a href="#tiles-annotations" id="markdown-toc-tiles-annotations">Tiles Annotations</a></li>
	</ul>

	<p>In many places, applications can use Java 5 annotations as an alternative to XML and Java properties configuration.
	This page serves as a reference for all annotations across the framework.</p>

	<h2 id="action-annotations">Action Annotations</h2>

	<p>Since Struts 2.1, these annotations are provided by the <a href="../plugins/convention/">Convention Plugin</a>. Codebehind and Zero Config
	plugins are deprecated from Struts 2.1 on.</p>

	<p>Action annotations are available when the framework scans the classpath for Action classes, rather than specifying
	individual mappings through XML configuration. See the <a href="../plugins/convention/">Convention Plugin</a> page for information
	on how to set up classpath scanning to allow the use of Action annotations.</p>

	<table>
	<thead>
	<tr>
	<th>Annotation</th>
	<th>Description</th>
	</tr>
	</thead>
	<tbody>
	<tr>
	<td><a href="../plugins/convention/#action-annotation">Actions Annotation</a></td>
	<td>Group of <code class="language-plaintext highlighter-rouge">@Action</code> annotations, maps multiple URLs to the same action</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#action-annotation">Action Annotation</a></td>
	<td>Defines the URL of an action</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#interceptorref-annotation">InterceptorRefs Annotation</a></td>
	<td>Group of <code class="language-plaintext highlighter-rouge">@InterceptorRef</code> annotations</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#interceptorref-annotation">InterceptorRef Annotation</a></td>
	<td>Interceptor, or interceptor stack to be applied to at action</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#result-annotation">Results Annotation</a></td>
	<td>Group of <code class="language-plaintext highlighter-rouge">@Result</code> annotations</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#result-annotation">Result Annotation</a></td>
	<td>Defines a result for an action</td>
	</tr>
	<tr>
	<td><a href="namespace-annotation">Namespace Annotation</a></td>
	<td>Set the path of the action URL (used to overwrite the default)</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#resultpath-annotation">ResultPath Annotation</a></td>
	<td>Set where the results are located (used to overwrite the default)</td>
	</tr>
	<tr>
	<td><a href="..//plugins/convention/#parentpackage-annotation">ParentPackage Annotation</a></td>
	<td>Set the parent package of the actions (used to overwrite the default)</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#exceptionmapping-annotation">ExceptionMappings</a></td>
	<td>Group of <code class="language-plaintext highlighter-rouge">@ExceptionMapping</code> annotations</td>
	</tr>
	<tr>
	<td><a href="../plugins/convention/#exceptionmapping-annotation">ExceptionMapping</a></td>
	<td>Defines an exception mapping</td>
	</tr>
	</tbody>
	</table>

	<h2 id="workflow-annotations">Workflow Annotations</h2>

	<table>
	<thead>
	<tr>
	<th>Annotation</th>
	<th>Description</th>
	</tr>
	</thead>
	<tbody>
	<tr>
	<td><a href="input-config-annotation">InputConfig Annotation</a></td>
	<td>Defines what method to execute, or result to be returned if there are validation errors</td>
	</tr>
	</tbody>
	</table>

	<h2 id="interceptor-annotations">Interceptor Annotations</h2>

	<p>To use these annotations, you have to specify the <a href="annotation-workflow-interceptor">AnnotationWorkflowInterceptor</a>
	to your interceptor stack.</p>

	<table>
	<thead>
	<tr>
	<th>Annotation</th>
	<th>Description</th>
	</tr>
	</thead>
	<tbody>
	<tr>
	<td><a href="after-annotation">After Annotation</a></td>
	<td>Marks a action method that needs to be executed after the result.</td>
	</tr>
	<tr>
	<td><a href="before-annotation">Before Annotation</a></td>
	<td>Marks a action method that needs to be executed before the main action method.</td>
	</tr>
	<tr>
	<td><a href="before-result-annotation">BeforeResult Annotation</a></td>
	<td>Marks a action method that needs to be executed before the result.</td>
	</tr>
	</tbody>
	</table>

	<h2 id="validation-annotations">Validation Annotations</h2>

	<p>To use annotation-based validation, annotate the class or interface with <a href="validation-annotation">Validation Annotation</a>.</p>

	<table>
	<thead>
	<tr>
	<th>Annotation</th>
	<th>Description</th>
	</tr>
	</thead>
	<tbody>
	<tr>
	<td><a href="conversion-error-field-validator-annotation">ConversionErrorFieldValidator Annotation</a></td>
	<td>Checks if there are any conversion errors for a field.</td>
	</tr>
	<tr>
	<td><a href="date-range-field-validator-annotation">DateRangeFieldValidator Annotation</a></td>
	<td>Checks that a date field has a value within a specified range.</td>
	</tr>
	<tr>
	<td><a href="double-range-field-validator-annotation">DoubleRangeFieldValidator Annotation</a></td>
	<td>Checks that a double field has a value within a specified range.</td>
	</tr>
	<tr>
	<td><a href="email-validator-annotation">EmailValidator Annotation</a></td>
	<td>Checks that a field is a valid e-mail address.</td>
	</tr>
	<tr>
	<td><a href="expression-validator-annotation">ExpressionValidator Annotation</a></td>
	<td>Validates an expression.</td>
	</tr>
	<tr>
	<td><a href="field-expression-validator-annotation">FieldExpressionValidator Annotation</a></td>
	<td>Uses an OGNL expression to perform its validator.</td>
	</tr>
	<tr>
	<td><a href="int-range-field-validator-annotation">IntRangeFieldValidator Annotation</a></td>
	<td>Checks that a numeric field has a value within a specified range.</td>
	</tr>
	<tr>
	<td><a href="regex-field-validator-annotation">RegexFieldValidator Annotation</a></td>
	<td>Validates a regular expression for a field.</td>
	</tr>
	<tr>
	<td><a href="required-field-validator-annotation">RequiredFieldValidator Annotation</a></td>
	<td>Checks that a field is non-null.</td>
	</tr>
	<tr>
	<td><a href="required-string-validator-annotation">RequiredStringValidator Annotation</a></td>
	<td>Checks that a String field is not empty.</td>
	</tr>
	<tr>
	<td><a href="string-length-field-validator-annotation">StringLengthFieldValidator Annotation</a></td>
	<td>Checks that a String field is of the right length.</td>
	</tr>
	<tr>
	<td><a href="url-validator-annotation">UrlValidator Annotation</a></td>
	<td>Checks that a field is a valid URL.</td>
	</tr>
	<tr>
	<td><a href="validation-annotation">Validation Annotation</a></td>
	<td>Marker annotation for validation at Type level.</td>
	</tr>
	<tr>
	<td><a href="validations-annotation">Validations Annotation</a></td>
	<td>Used to group validation annotations.</td>
	</tr>
	<tr>
	<td><a href="visitor-field-validator-annotation">VisitorFieldValidator Annotation</a></td>
	<td>Invokes the validation for a property’s object type.</td>
	</tr>
	<tr>
	<td><a href="custom-validator-annotation">CustomValidator Annotation</a></td>
	<td>Use this annotation for your custom validator types.</td>
	</tr>
	</tbody>
	</table>

	<h3 id="resources">Resources</h3>

	<ul>
	<li><a href="http://arsenalist.com/2007/05/10/struts-2-validation-using-annotations/">Validation using Annotations</a> (arsenalist)</li>
	</ul>

	<h2 id="type-conversion-annotations">Type Conversion Annotations</h2>

	<p>By default, type conversion for Maps and Collections using generics is directly supported.</p>

	<p>In short, instead of specifying the types found in collections and maps as documented
	in <a href="type-conversion">Type Conversion</a>, <strong>the collection’s generic type is used</strong>. By using annotations,
	an application should be able to avoid using any <code class="language-plaintext highlighter-rouge">ClassName-conversion.properties</code> files.</p>

	<p>To use annotation-based type conversion, annotate the class or interface with the <a href="conversion-annotation">Conversion Annotation</a>.</p>

	<table>
	<thead>
	<tr>
	<th>Annotation</th>
	<th>Description</th>
	</tr>
	</thead>
	<tbody>
	<tr>
	<td><a href="conversion-annotation">Conversion Annotation</a></td>
	<td>Marker annotation for type conversions at Type level.</td>
	</tr>
	<tr>
	<td><a href="create-if-null-annotation">CreateIfNull Annotation</a></td>
	<td>For Collection and Map types: Create the types within the Collection or Map, if null.</td>
	</tr>
	<tr>
	<td><a href="element-annotation">Element Annotation</a></td>
	<td>For Generic types: Specify the element type for Collection types and Map values.</td>
	</tr>
	<tr>
	<td><a href="key-annotation">Key Annotation</a></td>
	<td>For Generic types: Specify the key type for Map keys.</td>
	</tr>
	<tr>
	<td><a href="key-property-annotation">KeyProperty Annotation</a></td>
	<td>For Generic types: Specify the key property name value.</td>
	</tr>
	<tr>
	<td><a href="type-conversion-annotation">TypeConversion Annotation</a></td>
	<td>Used for class and application wide conversion rules.</td>
	</tr>
	</tbody>
	</table>

	<h2 id="tiles-annotations">Tiles Annotations</h2>

	<p>The <a href="../plugins/tiles/">Tiles Plugin</a> provides it’s own set of Annotations. They can be used to keep <code class="language-plaintext highlighter-rouge">tiles.xml</code> short.
	Instead tiles definitions can be created by annotating actions.</p>

	<table>
	<thead>
	<tr>
	<th>Annotation</th>
	<th>Description</th>
	</tr>
	</thead>
	<tbody>
	<tr>
	<td>TilesDefinition</td>
	<td>Represents a <code class="language-plaintext highlighter-rouge"><definition></code> element in tiles.xml</td>
	</tr>
	<tr>
	<td>TilesDefinitions</td>
	<td>A list of <code class="language-plaintext highlighter-rouge">TilesDefinition</code> Annotations</td>
	</tr>
	<tr>
	<td>TilesPutAttribute</td>
	<td>Represents a <code class="language-plaintext highlighter-rouge"><put-attribute></code> element in tiles.xml</td>
	</tr>
	<tr>
	<td>TilesPutListAttribute</td>
	<td>Represents a <code class="language-plaintext highlighter-rouge"><put-list-attribute></code> element in tiles.xml</td>
	</tr>
	<tr>
	<td>TilesAddAttribute</td>
	<td>Represents a <code class="language-plaintext highlighter-rouge"><add-attribute></code> element in tiles.xml</td>
	</tr>
	<tr>
	<td>TilesAddListAttribute</td>
	<td>Represents a <code class="language-plaintext highlighter-rouge"><add-list-attribute></code> element in tiles.xml</td>
	</tr>
	</tbody>
	</table>

	<p> </p>

	</section>
	</article>


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