// Copyright 2008, 2009, 2010 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.apache.tapestry5.internal.transform;
import java.util.List;
import org.apache.tapestry5.EventConstants;
import org.apache.tapestry5.annotations.PageActivationContext;
import org.apache.tapestry5.model.MutableComponentModel;
import org.apache.tapestry5.runtime.Component;
import org.apache.tapestry5.runtime.ComponentEvent;
import org.apache.tapestry5.services.ClassTransformation;
import org.apache.tapestry5.services.ComponentClassTransformWorker;
import org.apache.tapestry5.services.ComponentEventHandler;
import org.apache.tapestry5.services.FieldAccess;
import org.apache.tapestry5.services.TransformField;
/**
* Provides the page activation context handlers. This worker must be scheduled before
* {@link org.apache.tapestry5.internal.transform.OnEventWorker} in order for the added event handler methods to be
* properly picked up and processed.
*
* @see org.apache.tapestry5.annotations.PageActivationContext
*/
public class PageActivationContextWorker implements ComponentClassTransformWorker
{
public void transform(ClassTransformation transformation, MutableComponentModel model)
{
List<TransformField> fields = transformation.matchFieldsWithAnnotation(PageActivationContext.class);
// In the future we may add rules for ordering the fields (new attribute on annotation?)
if (fields.size() > 1)
throw new RuntimeException(TransformMessages.illegalNumberOfPageActivationContextHandlers(fields));
// So there's 0 or 1 of these
for (TransformField field : fields)
{
transformField(transformation, model, field);
}
}
private void transformField(ClassTransformation transformation, MutableComponentModel model, TransformField field)
{
PageActivationContext annotation = field.getAnnotation(PageActivationContext.class);
FieldAccess access = field.getAccess();
if (annotation.activate())
{
transformation.addComponentEventHandler(EventConstants.ACTIVATE, 1,
"PageActivationContextWorker activate event handler",
createActivationHandler(field.getType(), access));
}
if (annotation.passivate())
{
transformation.addComponentEventHandler(EventConstants.PASSIVATE, 0,
"PageActivationContextWorker passivate event handler", createPassivateHandler(access));
}
// We don't claim the field, and other workers may even replace it with a FieldValueConduit.
}
private static ComponentEventHandler createActivationHandler(final String fieldType, final FieldAccess access)
{
return new ComponentEventHandler()
{
public void handleEvent(Component instance, ComponentEvent event)
{
Object value = event.coerceContext(0, fieldType);
access.write(instance, value);
}
};
}
private static ComponentEventHandler createPassivateHandler(final FieldAccess access)
{
return new ComponentEventHandler()
{
public void handleEvent(Component instance, ComponentEvent event)
{
Object value = access.read(instance);
event.storeResult(value);
}
};
}
}