How to use ViewPreparer?

[hurelhuyag]

I tested sample ViewPreparer. but doesn't work.

@Component("testPreparer")
public class TestPreparer implements ViewPreparer {

    @Override
    public void execute(TilesRequestContext tilesContext, AttributeContext attributeContext) {
          attributeContext.putAttribute("message", new Attribute("hello world"));
    }
}

in definition:

<definition name="signin" template="signin" preparer="testPreparer" />

signin.html

...
<div th:text="${message}">prototype message</div>
...