[Simple-support] TransformMatcher

[Fabian K. <fab...@we...>]

Hi List,

I created two classes which could be useful for others aswell:
First, an Annotation:
/**
  * Use this annotation to indicate that your class can be transformed.
  *
  * @author Fabian Kürten
  * @version 0.1
  */
@Retention(RetentionPolicy.RUNTIME)
public @interface Transformable {

	/**
	 * The transformers type.
	 *
	 * @return the type
	 */
	public Class<? extends Transform<?>> type();

}

And second, the TransformMatcher:
/**
  * This Matcher looks for the {@link Transformable} annotation to create a
  * suitable {@link Transform}.
  *
  * @see Transformable
  * @author Fabian K&uuml;rten
  * @version 0.1
  */
public class TransformMatcher
		implements
			Matcher {

	private final Matcher delegate;

	/**
	 * Creates the Matcher.
	 */
	public TransformMatcher() {
		this.delegate = null;
	}

	/**
	 * Creates the Matcher with a delegate Matcher.
	 *
	 * @param delegate the delegate will be called if no match could be found
	 */
	public TransformMatcher(Matcher delegate) {
		this.delegate = delegate;

	}

	public Transform match(Class type) throws Exception {
		Class<?> type2 = type;
		Transformable t = type2.getAnnotation(Transformable.class);
		if (t != null) {
			Class<?> transformerClass = t.type();
			Transform<?> transformer = (Transform<?>) transformerClass.newInstance();
			return transformer;
		} // t != null
		if (this.delegate != null) {
			return this.delegate.match(type);
		} else {
			return null;
		}
	}

}

The usage is quite simple, you have to use the Matcher of course:
Serializer serializer = new Persister(new TransformMatcher());
and annotate your class:
@Root
@Transformable(type=full.package.name.MyTransform.class)
public final class MyClass

I hope someone finds this useful.

Fabian