// Copyright 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 org.apache.tapestry5.EventConstants;
import org.apache.tapestry5.Link;
import org.apache.tapestry5.ValueEncoder;
import org.apache.tapestry5.annotations.ActivationRequestParameter;
import org.apache.tapestry5.internal.services.ComponentClassCache;
import org.apache.tapestry5.ioc.util.IdAllocator;
import org.apache.tapestry5.model.MutableComponentModel;
import org.apache.tapestry5.runtime.Component;
import org.apache.tapestry5.runtime.ComponentEvent;
import org.apache.tapestry5.services.*;
/**
* Hooks the activate event handler on the component (presumably, a page) to
* extract query parameters, and hooks the link decoration events to extract values
* and add them to the {@link Link}.
*
* @see ActivationRequestParameter
* @since 5.2.0
*/
@SuppressWarnings("all")
public class ActivationRequestParameterWorker implements ComponentClassTransformWorker
{
private final Request request;
private final ComponentClassCache classCache;
private final ValueEncoderSource valueEncoderSource;
public ActivationRequestParameterWorker(Request request, ComponentClassCache classCache,
ValueEncoderSource valueEncoderSource)
{
this.request = request;
this.classCache = classCache;
this.valueEncoderSource = valueEncoderSource;
}
public void transform(ClassTransformation transformation, MutableComponentModel model)
{
for (TransformField field : transformation.matchFieldsWithAnnotation(ActivationRequestParameter.class))
{
mapFieldToQueryParameter(field, transformation, model);
}
}
private void mapFieldToQueryParameter(TransformField field, ClassTransformation transformation,
MutableComponentModel model)
{
ActivationRequestParameter annotation = field.getAnnotation(ActivationRequestParameter.class);
String parameterName = getParameterName(field, annotation);
// Assumption: the field type is not one that's loaded by the component class loader, so it's safe
// to convert to a hard type during class transformation.
Class fieldType = classCache.forName(field.getType());
ValueEncoder encoder = valueEncoderSource.getValueEncoder(fieldType);
FieldAccess access = field.getAccess();
setValueFromInitializeEventHandler(transformation, access, parameterName, encoder);
decorateLinks(transformation, access, parameterName, encoder);
preallocateName(transformation, parameterName);
}
private static void preallocateName(ClassTransformation transformation, final String parameterName)
{
ComponentEventHandler handler = new ComponentEventHandler()
{
public void handleEvent(Component instance, ComponentEvent event)
{
IdAllocator idAllocator = event.getEventContext().get(IdAllocator.class, 0);
idAllocator.allocateId(parameterName);
}
};
transformation.addComponentEventHandler(EventConstants.PREALLOCATE_FORM_CONTROL_NAMES, 1,
"ActivationRequestParameterWorker preallocate form control name '" + parameterName + "' event handler",
handler);
}
@SuppressWarnings("all")
private void setValueFromInitializeEventHandler(ClassTransformation transformation, final FieldAccess access,
final String parameterName, final ValueEncoder encoder)
{
ComponentEventHandler handler = new ComponentEventHandler()
{
public void handleEvent(Component instance, ComponentEvent event)
{
String clientValue = request.getParameter(parameterName);
if (clientValue == null)
return;
Object value = encoder.toValue(clientValue);
access.write(instance, value);
}
};
transformation.addComponentEventHandler(EventConstants.ACTIVATE, 0,
"ActivationRequestParameterWorker activate event handler", handler);
}
@SuppressWarnings("all")
private static void decorateLinks(ClassTransformation transformation, final FieldAccess access,
final String parameterName, final ValueEncoder encoder)
{
ComponentEventHandler handler = new ComponentEventHandler()
{
public void handleEvent(Component instance, ComponentEvent event)
{
Object value = access.read(instance);
if (value == null)
return;
Link link = event.getEventContext().get(Link.class, 0);
String clientValue = encoder.toClient(value);
link.addParameter(parameterName, clientValue);
}
};
transformation.addComponentEventHandler(EventConstants.DECORATE_COMPONENT_EVENT_LINK, 0,
"ActivationRequestParameterWorker decorate component event link event handler", handler);
transformation.addComponentEventHandler(EventConstants.DECORATE_PAGE_RENDER_LINK, 0,
"ActivationRequestParameterWorker decorate page render link event handler", handler);
}
private String getParameterName(TransformField field, ActivationRequestParameter annotation)
{
if (annotation.value().equals(""))
return field.getName();
return annotation.value();
}
}