/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.wicket.markup.transformer;
import org.apache.wicket.Component;
import org.apache.wicket.Page;
import org.apache.wicket.WicketRuntimeException;
import org.apache.wicket.behavior.Behavior;
import org.apache.wicket.protocol.http.BufferedWebResponse;
import org.apache.wicket.request.Response;
import org.apache.wicket.request.cycle.RequestCycle;
import org.apache.wicket.request.http.WebResponse;
/**
* A {@link Behavior} which can be added to any component. It allows to post-process (transform) the
* markup generated by the component.
*
* @see org.apache.wicket.markup.transformer.AbstractOutputTransformerContainer
*
* @author Juergen Donnerstag
*/
public abstract class AbstractTransformerBehavior extends Behavior implements ITransformer
{
private static final long serialVersionUID = 1L;
/**
* The request cycle's response before the transformation.
*/
private transient Response originalResponse;
/**
* Create a new response object which is used to store the markup generated by the child
* objects.
*
* @param originalResponse
* the original web response or {@code null} if it isn't a {@link WebResponse}
*
* @return Response object. Must not be null
*/
protected BufferedWebResponse newResponse(final WebResponse originalResponse)
{
return new BufferedWebResponse(originalResponse);
}
@Override
public void beforeRender(Component component)
{
super.beforeRender(component);
final RequestCycle requestCycle = RequestCycle.get();
// Temporarily replace the web response with a String response
originalResponse = requestCycle.getResponse();
WebResponse origResponse = (WebResponse)((originalResponse instanceof WebResponse)
? originalResponse : null);
BufferedWebResponse tempResponse = newResponse(origResponse);
// temporarily set StringResponse to collect the transformed output
requestCycle.setResponse(tempResponse);
}
@Override
public void afterRender(final Component component)
{
final RequestCycle requestCycle = RequestCycle.get();
try
{
BufferedWebResponse tempResponse = (BufferedWebResponse)requestCycle.getResponse();
if (component instanceof Page && originalResponse instanceof WebResponse)
{
tempResponse.writeMetaData((WebResponse) originalResponse);
}
// Transform the data
CharSequence output = transform(component, tempResponse.getText());
originalResponse.write(output);
}
catch (Exception ex)
{
throw new WicketRuntimeException("Error while transforming the output of component: " +
component, ex);
}
finally
{
// Restore the original response object
requestCycle.setResponse(originalResponse);
}
}
@Override
public void detach(Component component)
{
originalResponse = null;
super.detach(component);
}
@Override
public abstract CharSequence transform(final Component component, final CharSequence output)
throws Exception;
}