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Wicket comes with some templating facilities. They’re often handy, especially when integrating JavaScript components.

Yet, for some reasons I don’t get, these functionalities aren’t much advertised. Anyway, let’s dig in !

Basically, this templating is about some text containing variables, for example ${variable}, whose values are provided through Java code.

Let’s take a simple example, a template file named javascript.tpl containing :

alert('${variable}');

Wicket is nice enough to provide an easy to access the templates as package resources, through the PackagedTextTemplate class :

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public PackagedTextTemplate(final Class< ? > clazz, final String fileName)

For example :

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PackagedTextTemplate jsTemplate = new PackagedTextTemplate(this.getClass(), "javascript.tpl");

Thus the template can be next to the .html page and the Java class using it, making the whole quite cohesive.

Providing the variables is done through a simple Map :

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Map< String , Object > parameters = new HashMap< String , Object >();
parameters.put("variable","test working");

And then, you most probably want to include this template in some html. Wicket provides you different options :

• as an header contribution :
  

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  add(TextTemplateHeaderContributor.forJavaScript(jsTemplate, new  Model((Serializable) parameters)));

• directly next to some element in the html file:
  Java side :
  

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  Label myScript = new Label("myScript", new JavaScriptTemplate(jsTemplate).asString(parameters));
  myScript.setEscapeModelStrings(false);
  add(myScript);

  Html side :
  

  <wicket:container wicket:id="myScript"></wicket:container>

You may have noticed that, in both cases, I didn’t provided the surrounding script tag (and the appropriate inner wrapping). Fear not, Wicket does it for you !
Indeed, the rendered html is :

<script type="text/javascript"><!--/*--><![CDATA[/*><!--*/
alert('test working');
/*-->]]>*/</script>

If the template was about some CSS stuff, one would just need to warp it using a CssTemplate instead of the JavaScriptTemplate.

A bit more info are available there Including CSS resources.

++
joseph