juneau-doc/docs/Topics/02.juneau-marshall/12.Transforms/07.TemplatedSwaps.html

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Templated Swaps

<p>
	The {@link oaj.annotation.Swap#template() @Swap(template)} annotation allows you to associate
	arbitrary contextual strings with swaps.
	The primary purpose is for providing template names, such as for Apache FreeMarker, therefore
	the name 'template'.
	However, the usage of the string is open-ended.
</p>
<p>
	For example, you could pair a template string like so:
</p>
<p class='bpcode w800'>
	<ja>@Swap</ja>(impl=FreeMarkerSwap.<jk>class</jk>, template=<js>"MyPojo.div.ftl"</js>)
	<jk>public class</jk> MyPojo {}
</p>
<p>
	The implementation of the FreeMarker swap would look something like this:
</p>
<p class='bpcode w800'>
	<jc>// Our templated swap class.</jc>
	<jk>public class</jk> FreeMarkerSwap <jk>extends</jk> PojoSwap&lt;Object,Reader&gt; {

		<jk>public</jk> MediaType[] forMediaTypes() {
			<jc>// Make sure this only applies to the HTML serializer.</jc>
			<jk>return</jk> MediaType.<jsm>forStrings</jsm>(<js>"&#42;/html"</js>);
		}

		<jk>public</jk> Reader swap(BeanSession session, Object o, String template) <jk>throws</jk> Exception {
			<jc>// Call some method that uses FreeMarker to convert 'o' to raw HTML using </jc>
			<jc>// the 'MyPojo.div.ftl' template.</jc>
			<jk>return</jk> getFreeMarkerReader(template, o);  
		}
	}
</p>