// Copyright 2014 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.services;
import org.apache.tapestry5.TapestryConstants;
import org.apache.tapestry5.ioc.IOOperation;
import org.apache.tapestry5.ioc.OperationTracker;
import org.apache.tapestry5.services.*;
import java.io.IOException;
/**
* After processing the component event request (including Ajax requests), or the page render request,
* checks for the {@link org.apache.tapestry5.TapestryConstants#RESPONSE_RENDERER} request attribute,
* and invokes it to render the deferred response.
*
* @since 5.4
*/
public class DeferredResponseRenderer implements ComponentRequestFilter
{
private final Request request;
private final OperationTracker tracker;
public DeferredResponseRenderer(Request request, OperationTracker tracker)
{
this.request = request;
this.tracker = tracker;
}
public void handleComponentEvent(ComponentEventRequestParameters parameters, ComponentRequestHandler handler) throws IOException
{
handler.handleComponentEvent(parameters);
invokeQueuedRenderer();
}
public void handlePageRender(PageRenderRequestParameters parameters, ComponentRequestHandler handler) throws IOException
{
handler.handlePageRender(parameters);
invokeQueuedRenderer();
}
private void invokeQueuedRenderer() throws IOException
{
while (true)
{
IOOperation responseRenderer = (IOOperation) request.getAttribute(TapestryConstants.RESPONSE_RENDERER);
if (responseRenderer == null)
{
break;
}
// There's a particular case where an operation puts a different operation into the attribute;
// we'll handle that on the next pass.
request.setAttribute(TapestryConstants.RESPONSE_RENDERER, null);
tracker.perform("Executing deferred response renderer.", responseRenderer);
}
}
}