//========================================================================
//$Id: WrappedHandler.java,v 1.2 2005/11/11 22:55:39 gregwilkins Exp $
//Copyright 2004-2006 Mort Bay Consulting Pty. Ltd.
//------------------------------------------------------------------------
//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.mortbay.jetty.handler;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.mortbay.component.LifeCycle;
import org.mortbay.jetty.Handler;
import org.mortbay.jetty.HandlerContainer;
import org.mortbay.jetty.Server;
/* ------------------------------------------------------------ */
/** A <code>HandlerWrapper</code> acts as a {@link Handler} but delegates the {@link Handler#handle handle} method and
* {@link LifeCycle life cycle} events to a delegate. This is primarily used to implement the <i>Decorator</i> pattern.
* @author gregw
*/
public class HandlerWrapper extends AbstractHandlerContainer
{
private Handler _handler;
/* ------------------------------------------------------------ */
/**
*
*/
public HandlerWrapper()
{
super();
}
/* ------------------------------------------------------------ */
/**
* @return Returns the handlers.
*/
public Handler getHandler()
{
return _handler;
}
/* ------------------------------------------------------------ */
/**
* @param handler Set the {@link Handler} which should be wrapped.
*/
public void setHandler(Handler handler)
{
try
{
Handler old_handler = _handler;
if (getServer()!=null)
getServer().getContainer().update(this, old_handler, handler, "handler");
if (handler!=null)
{
handler.setServer(getServer());
}
_handler = handler;
if (old_handler!=null)
{
if (old_handler.isStarted())
old_handler.stop();
}
}
catch(Exception e)
{
IllegalStateException ise= new IllegalStateException();
ise.initCause(e);
throw ise;
}
}
/* ------------------------------------------------------------ */
/** Add a handler.
* This implementation of addHandler calls setHandler with the
* passed handler. If this HandlerWrapper had a previous wrapped
* handler, then it is passed to a call to addHandler on the passed
* handler. Thus this call can add a handler in a chain of
* wrapped handlers.
*
* @param handler
*/
public void addHandler(Handler handler)
{
Handler old = getHandler();
if (old!=null && !(handler instanceof HandlerContainer))
throw new IllegalArgumentException("Cannot add");
setHandler(handler);
if (old!=null)
((HandlerContainer)handler).addHandler(old);
}
public void removeHandler (Handler handler)
{
Handler old = getHandler();
if (old!=null && (old instanceof HandlerContainer))
((HandlerContainer)old).removeHandler(handler);
else if (old!=null && handler.equals(old))
setHandler(null);
else
throw new IllegalStateException("Cannot remove");
}
/* ------------------------------------------------------------ */
/*
* @see org.mortbay.thread.AbstractLifeCycle#doStart()
*/
protected void doStart() throws Exception
{
if (_handler!=null)
_handler.start();
super.doStart();
}
/* ------------------------------------------------------------ */
/*
* @see org.mortbay.thread.AbstractLifeCycle#doStop()
*/
protected void doStop() throws Exception
{
super.doStop();
if (_handler!=null)
_handler.stop();
}
/* ------------------------------------------------------------ */
/*
* @see org.mortbay.jetty.EventHandler#handle(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
public void handle(String target, HttpServletRequest request, HttpServletResponse response, int dispatch) throws IOException, ServletException
{
if (_handler!=null && isStarted())
_handler.handle(target,request, response, dispatch);
}
/* ------------------------------------------------------------ */
public void setServer(Server server)
{
Server old_server=getServer();
super.setServer(server);
Handler h=getHandler();
if (h!=null)
h.setServer(server);
if (server!=null && server!=old_server)
server.getContainer().update(this, null,_handler, "handler");
}
/* ------------------------------------------------------------ */
protected Object expandChildren(Object list, Class byClass)
{
return expandHandler(_handler,list,byClass);
}
}