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<p>The primary goals of this example are to introduce you to the following:</p>
<ol>
	<li><a class="confluence-link" href="#transformer" data-anchor="transformer" data-linked-resource-default-alias="transformer" data-base-url="http://docs.codehaus.org">A very basic <strong>Fragment</strong> Transformer written in Java</a>.</li>
	<li><a class="confluence-link" href="#configuration" data-anchor="configuration" data-linked-resource-default-alias="configuration" data-base-url="http://docs.codehaus.org">The Smooks configuration file</a>.</li>
	<li><a class="confluence-link" href="#execution" data-anchor="execution" data-linked-resource-default-alias="execution" data-base-url="http://docs.codehaus.org">Executing the Smooks Transformation</a>.</li>
</ol>

<p> <br />
<strong><a href="http://svn.codehaus.org/milyn/trunk/smooks-examples/java-basic">SVN</a></strong> - <strong><a class="confluence-link unresolved" data-content-title="downloads" data-linked-resource-default-alias="downloads" href="#">Download</a></strong> - <strong><a class="confluence-link" href="/display/MILYN/Tutorials" data-linked-resource-id="49525" data-linked-resource-type="page" data-linked-resource-default-alias="Tutorials" data-base-url="http://docs.codehaus.org">Other Tutorials</a></strong></p>

<p><span style="text-decoration: underline;">To Build</span>: &quot;mvn clean install&quot;<br />
<span style="text-decoration: underline;">To Run</span>: &quot;mvn exec:java&quot;</p>

<p><img class="editor-inline-macro" src="/plugins/servlet/confluence/placeholder/macro?definition=e2FuY2hvcjp0cmFuc2Zvcm1lcn0&amp;locale=en_GB&amp;version=2" data-macro-name="anchor" data-macro-default-parameter="transformer"></p>
<h1>The Fragment Transformer</h1>
<p>Smooks is a <strong>Fragment</strong> based Transformation Framework.  That means you can write (or reuse) Transformers that apply transformations on message fragments, as opposed to the message as a whole.</p>

<p>In this example we build a very simple (silly) fragment transformer in raw Java.  Smooks supports applying transformations through a number of technologies (not just Java).  However, underpinning all of these is an <a class="confluence-link" href="/display/MILYN/Visitor" data-linked-resource-id="78568" data-linked-resource-type="page" data-linked-resource-default-alias="Visitor" data-base-url="http://docs.codehaus.org">Element Visitor</a> implementation of one sort or another.  All transformation technologies supported by Smooks are hooked into the transformation process through an implementation of an <a class="confluence-link" href="/display/MILYN/Visitor" data-linked-resource-id="78568" data-linked-resource-type="page" data-linked-resource-default-alias="Visitor" data-base-url="http://docs.codehaus.org">Element Visitor</a>.</p>

<p>In this example, we implement a very simple <a class="confluence-link" href="http://milyn.codehaus.org/javadoc/smooks/org/milyn/delivery/dom/DOMElementVisitor.html" shortcut-key="milyn_public_html" shortcut-parameter="javadoc/smooks/org/milyn/delivery/dom/DOMElementVisitor.html" data-linked-resource-default-alias="unnamed link" data-base-url="http://docs.codehaus.org">DOMElementVisitor</a> that simply renames the DOM Element of the fragment at which it is &quot;targeted&quot;.</p>
<table class="wysiwyg-macro" data-macro-name="noformat" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e25vZm9ybWF0fQ&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
//example/BasicJavaTransformer.java
public class BasicJavaTransformer implements DOMElementVisitor {

private String newElementName;

public void setConfiguration(SmooksResourceConfiguration resourceConfig) 
                                 throws SmooksConfigurationException {
        newElementName = resourceConfig.getStringParameter("newName");
    }
    
    public void visitBefore(Element element, ExecutionContext executionContext) {
        // Not doing anything on this visit - wait until after visiting 
        // the elements child content...
    }

public void visitAfter(Element element, ExecutionContext executionContext) {
        // Just rename the target element - keeping child elements - not keeping attributes.
        DomUtils.renameElement(element, newElementName, true, false);
    }
}
</pre></td></tr></table>

<p>As you can see from the code, the implementation gets the new name for the targeted fragment via the configuration (in the <strong>setConfiguration</strong> method).  It doesn't apply any transformation on the <strong>visitBefore</strong> event.  On the <strong>visitAfter</strong> event, it applies the rename transformation on the targeted Element (message fragment) (See <a class="confluence-link" href="http://milyn.codehaus.org/javadoc/smooks/org/milyn/xml/DomUtils.html#renameElement(org.w3c.dom.Element,%20java.lang.String,%20boolean,%20boolean)" shortcut-key="milyn_public_html" shortcut-parameter="javadoc/smooks/org/milyn/xml/DomUtils.html#renameElement(org.w3c.dom.Element,%20java.lang.String,%20boolean,%20boolean)" data-linked-resource-default-alias="unnamed link" data-base-url="http://docs.codehaus.org">DomUtils.html.renameElement</a>).</p>

<p><img class="editor-inline-macro" src="/plugins/servlet/confluence/placeholder/macro?definition=e2FuY2hvcjpjb25maWd1cmF0aW9ufQ&amp;locale=en_GB&amp;version=2" data-macro-name="anchor" data-macro-default-parameter="configuration"></p>
<h1>The Smooks Configuration</h1>
<p>In order to apply this transformer to a message fragment, a <a class="confluence-link" href="http://milyn.codehaus.org/javadoc/smooks/org/milyn/cdr/SmooksResourceConfiguration.html" shortcut-key="milyn_public_html" shortcut-parameter="javadoc/smooks/org/milyn/cdr/SmooksResourceConfiguration.html" data-linked-resource-default-alias="unnamed link" data-base-url="http://docs.codehaus.org">Smooks Configuration</a> needs to be created.  This configuration will target the transformer at a particular message fragment.</p>

<p>Here's the configuration (&quot;smooks-config.xml&quot;):</p>
<table class="wysiwyg-macro" data-macro-name="noformat" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e25vZm9ybWF0fQ&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
&lt;?xml version="1.0"?>
&lt;smooks-resource-list xmlns="http://www.milyn.org/xsd/smooks-1.0.xsd">

&lt;resource-config selector="c b">
	    &lt;resource>example.BasicJavaTransformer&lt;/resource>
	    &lt;param name="newName">xxx&lt;/param>
	&lt;/resource-config>

&lt;/smooks-resource-list>
</pre></td></tr></table>

<p>The <strong>resource-config</strong> is what's most important here.  It tells Smooks to apply the &quot;example.BasicJavaTransformer&quot; <strong>resource</strong> on all &lt;b&gt; elements that are enclosed by a parent &lt;c&gt; element.  This is what's called a &quot;Contextual Selector&quot;.  Contextual Selectors follow the same basic rules as their <a href="http://www.w3.org/TR/CSS1#contextual-selectors">namesake from the CSS Spec</a>.</p>

<p>So, taking the sample message supplied with this example:</p>
<table class="wysiwyg-macro" data-macro-name="noformat" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e25vZm9ybWF0fQ&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
&lt;a>
    &lt;b>
        &lt;c>
            &lt;b>&lt;/b>
        &lt;/c>
    &lt;/b>
&lt;/a>
</pre></td></tr></table>

<p>The instance of the &quot;example.BasicJavaTransformer&quot; <strong>resource</strong> created for the above configuration will only be applied to the inner most &lt;b&gt; element, producing the following output:</p>
<table class="wysiwyg-macro" data-macro-name="noformat" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e25vZm9ybWF0fQ&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
&lt;a>
    &lt;b>
        &lt;c>
            &lt;xxx>&lt;/xxx>
        &lt;/c>
    &lt;/b>
&lt;/a>
</pre></td></tr></table>

<p><img class="editor-inline-macro" src="/plugins/servlet/confluence/placeholder/macro?definition=e2FuY2hvcjpleGVjdXRpb259&amp;locale=en_GB&amp;version=2" data-macro-name="anchor" data-macro-default-parameter="execution"></p>
<h1>Executing The Transformation</h1>
<p>Executing the transform is a piece of cake.  To do this we use the <a class="confluence-link" href="http://milyn.codehaus.org/javadoc/smooks/org/milyn/Smooks.html" shortcut-key="milyn_public_html" shortcut-parameter="javadoc/smooks/org/milyn/Smooks.html" data-linked-resource-default-alias="unnamed link" data-base-url="http://docs.codehaus.org">Smooks</a> class as follows:</p>
<table class="wysiwyg-macro" data-macro-name="noformat" style="background-image: url(/plugins/servlet/confluence/placeholder/macro-heading?definition=e25vZm9ybWF0fQ&amp;locale=en_GB&amp;version=2); background-repeat: no-repeat;" data-macro-body-type="PLAIN_TEXT"><tr><td class="wysiwyg-macro-body"><pre>
// Instantiate Smooks with the config...
Smooks smooks = new Smooks("smooks-config.xml);

// Filter the input message to the outputWriter...
smooks.filter(new StreamSource(messageInStream), new StreamResult(messageOutStream));
</pre></td></tr></table>

<p>Of course, you'd typically cache the <a class="confluence-link" href="http://milyn.codehaus.org/javadoc/smooks/org/milyn/Smooks.html" shortcut-key="milyn_public_html" shortcut-parameter="javadoc/smooks/org/milyn/Smooks.html" data-linked-resource-default-alias="unnamed link" data-base-url="http://docs.codehaus.org">Smooks</a> instance.</p>

<p>See the <a href="http://svn.codehaus.org/milyn/trunk/smooks-examples/java-basic/src/main/java/example/Main.java">example/Main.java</a> in the example source.</p>