/*
* 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.core.request.handler;
import org.apache.wicket.Application;
import org.apache.wicket.request.IRequestCycle;
import org.apache.wicket.request.IRequestHandler;
import org.apache.wicket.request.http.WebResponse;
/**
* The empty AJAX request target does output an empty AJAX response.
* <br/>
* May be used as a light, "do nothing" Ajax response.
*
* @author Matej Knopp
*/
public final class EmptyAjaxRequestHandler implements IRequestHandler
{
/** immutable hashcode. */
private static final int HASH = 17 * 1542323;
/** singleton instance. */
private static final EmptyAjaxRequestHandler instance = new EmptyAjaxRequestHandler();
/**
* Construct.
*/
private EmptyAjaxRequestHandler()
{
}
/**
* Gets the singleton instance.
*
* @return the singleton instance
*/
public static EmptyAjaxRequestHandler getInstance()
{
return instance;
}
/** {@inheritDoc} */
@Override
public void respond(IRequestCycle requestCycle)
{
WebResponse response = (WebResponse)requestCycle.getResponse();
final String encoding = Application.get()
.getRequestCycleSettings()
.getResponseRequestEncoding();
// Set content type based on markup type for page
response.setContentType("text/xml; charset=" + encoding);
// Make sure it is not cached by a client
response.disableCaching();
response.write("<?xml version=\"1.0\" encoding=\"");
response.write(encoding);
response.write("\"?><ajax-response></ajax-response>");
}
/** {@inheritDoc} */
@Override
public void detach(IRequestCycle requestCycle)
{
}
/**
* @see java.lang.Object#equals(java.lang.Object)
*/
@Override
public boolean equals(Object obj)
{
return obj instanceof EmptyAjaxRequestHandler;
}
/**
* @see java.lang.Object#hashCode()
*/
@Override
public int hashCode()
{
return HASH;
}
/**
* @see java.lang.Object#toString()
*/
@Override
public String toString()
{
return "EmptyAjaxRequestTarget";
}
}