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     <a class="edit-on-gh" href="https://github.com/apache/struts-site/edit/master/source/core-developers/model-driven-interceptor.md" title="Edit this page on GitHub">Edit on GitHub</a>

     <a href="interceptors.html" title="back to Interceptors"><< back to Interceptors</a>

     <h1 id="model-driven-interceptor">Model Driven Interceptor</h1>

 <p>Watches for <code class="language-plaintext highlighter-rouge">ModelDriven</code> actions and adds the action’s model on to the value stack.</p>

 <blockquote>
   <p>The <code class="language-plaintext highlighter-rouge">ModelDrivenInterceptor</code> must come before the both <code class="language-plaintext highlighter-rouge">StaticParametersInterceptor</code> and <code class="language-plaintext highlighter-rouge">ParametersInterceptor</code>
 if you want the parameters to be applied to the model.</p>
 </blockquote>

 <blockquote>
   <p>The <code class="language-plaintext highlighter-rouge">ModelDrivenInterceptor</code> will only push the model into the stack when the model is not null, else it will be ignored.</p>
 </blockquote>

 <p>To create a Model Driven action, implement the <code class="language-plaintext highlighter-rouge">ModelDriven</code> interface by adding a model property, or at least the accessor.</p>

 <div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">public</span> <span class="nc">Object</span> <span class="nf">getModel</span><span class="o">();</span>
 </code></pre></div></div>

 <p>In the implementation of <code class="language-plaintext highlighter-rouge">getModel</code>, acquire an instance of a business object and return it.</p>

 <p>On the page, you can address any JavaBean properties on the business object as if they were coded directly on the Action
 class. The framework pushes the Model object onto the ValueStack.</p>

 <p>Many developers use Spring to acquire the business object. With the addition of a <code class="language-plaintext highlighter-rouge">setModel</code> method, the business logic
 can be injected automatically.</p>

 <h2 id="parameters">Parameters</h2>

 <ul>
   <li><code class="language-plaintext highlighter-rouge">refreshModelBeforeResult</code> - set to true if you want the model to be refreshed on the value stack after action
 execution and before result execution. The setting is useful if you want to change the model instance during the
 action execution phase, like when loading it from the data layer. This will result in <code class="language-plaintext highlighter-rouge">getModel()</code> being called at
 least twice.</li>
 </ul>

 <h2 id="extending-the-interceptor">Extending the Interceptor</h2>

 <p>There are no known extension points to this interceptor.</p>

 <h2 id="examples">Examples</h2>

 <div class="language-xml highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="nt">&lt;action</span> <span class="na">name=</span><span class="s">"someAction"</span> <span class="na">class=</span><span class="s">"com.examples.SomeAction"</span><span class="nt">&gt;</span>
     <span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"modelDriven"</span><span class="nt">/&gt;</span>
     <span class="nt">&lt;interceptor-ref</span> <span class="na">name=</span><span class="s">"basicStack"</span><span class="nt">/&gt;</span>
      <span class="nt">&lt;result</span> <span class="na">name=</span><span class="s">"success"</span><span class="nt">&gt;</span>good_result.ftl<span class="nt">&lt;/result&gt;</span>
  <span class="nt">&lt;/action&gt;</span>
 </code></pre></div></div>

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	<a class="edit-on-gh" href="https://github.com/apache/struts-site/edit/master/source/core-developers/model-driven-interceptor.md" title="Edit this page on GitHub">Edit on GitHub</a>

	<a href="interceptors.html" title="back to Interceptors"><< back to Interceptors</a>

	<h1 id="model-driven-interceptor">Model Driven Interceptor</h1>

	<p>Watches for <code class="language-plaintext highlighter-rouge">ModelDriven</code> actions and adds the action’s model on to the value stack.</p>

	<blockquote>
	<p>The <code class="language-plaintext highlighter-rouge">ModelDrivenInterceptor</code> must come before the both <code class="language-plaintext highlighter-rouge">StaticParametersInterceptor</code> and <code class="language-plaintext highlighter-rouge">ParametersInterceptor</code>
	if you want the parameters to be applied to the model.</p>
	</blockquote>

	<blockquote>
	<p>The <code class="language-plaintext highlighter-rouge">ModelDrivenInterceptor</code> will only push the model into the stack when the model is not null, else it will be ignored.</p>
	</blockquote>

	<p>To create a Model Driven action, implement the <code class="language-plaintext highlighter-rouge">ModelDriven</code> interface by adding a model property, or at least the accessor.</p>

	<div class="language-java highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="kd">public</span> <span class="nc">Object</span> <span class="nf">getModel</span><span class="o">();</span>
	</code></pre></div></div>

	<p>In the implementation of <code class="language-plaintext highlighter-rouge">getModel</code>, acquire an instance of a business object and return it.</p>

	<p>On the page, you can address any JavaBean properties on the business object as if they were coded directly on the Action
	class. The framework pushes the Model object onto the ValueStack.</p>

	<p>Many developers use Spring to acquire the business object. With the addition of a <code class="language-plaintext highlighter-rouge">setModel</code> method, the business logic
	can be injected automatically.</p>

	<h2 id="parameters">Parameters</h2>

	<ul>
	<li><code class="language-plaintext highlighter-rouge">refreshModelBeforeResult</code> - set to true if you want the model to be refreshed on the value stack after action
	execution and before result execution. The setting is useful if you want to change the model instance during the
	action execution phase, like when loading it from the data layer. This will result in <code class="language-plaintext highlighter-rouge">getModel()</code> being called at
	least twice.</li>
	</ul>

	<h2 id="extending-the-interceptor">Extending the Interceptor</h2>

	<p>There are no known extension points to this interceptor.</p>

	<h2 id="examples">Examples</h2>

	<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">"someAction"</span> <span class="na">class=</span><span class="s">"com.examples.SomeAction"</span><span class="nt">></span>
	<span class="nt"><interceptor-ref</span> <span class="na">name=</span><span class="s">"modelDriven"</span><span class="nt">/></span>
	<span class="nt"><interceptor-ref</span> <span class="na">name=</span><span class="s">"basicStack"</span><span class="nt">/></span>
	<span class="nt"><result</span> <span class="na">name=</span><span class="s">"success"</span><span class="nt">></span>good_result.ftl<span class="nt"></result></span>
	<span class="nt"></action></span>
	</code></pre></div></div>

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