org.eclipse.jetty.server.handler.AbstractHandler Maven / Gradle / Ivy
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// Copyright (c) 1995-2018 Mort Bay Consulting Pty. Ltd.
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// All rights reserved. This program and the accompanying materials
// are made available under the terms of the Eclipse Public License v1.0
// and Apache License v2.0 which accompanies this distribution.
//
// The Eclipse Public License is available at
// http://www.eclipse.org/legal/epl-v10.html
//
// The Apache License v2.0 is available at
// http://www.opensource.org/licenses/apache2.0.php
//
// You may elect to redistribute this code under either of these licenses.
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//
package org.eclipse.jetty.server.handler;
import java.io.IOException;
import javax.servlet.DispatcherType;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.eclipse.jetty.server.Handler;
import org.eclipse.jetty.server.HttpChannel;
import org.eclipse.jetty.server.HttpConnection;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.Response;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.component.ContainerLifeCycle;
import org.eclipse.jetty.util.component.Dumpable;
import org.eclipse.jetty.util.log.Log;
import org.eclipse.jetty.util.log.Logger;
/** AbstractHandler.
* A convenience implementation of {@link Handler} that uses the
* {@link ContainerLifeCycle} to provide:
* - start/stop behavior
*
- a bean container
*
- basic {@link Dumpable} support
*
- a {@link Server} reference
*
- optional error dispatch handling
*
*/
@ManagedObject("Jetty Handler")
public abstract class AbstractHandler extends ContainerLifeCycle implements Handler
{
private static final Logger LOG = Log.getLogger(AbstractHandler.class);
private Server _server;
/**
*
*/
public AbstractHandler()
{
}
@Override
public abstract void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException;
/**
* Convenience method to generate error page.
* This method can be called from {@link #handle(String, Request, HttpServletRequest, HttpServletResponse)} when an {@link DispatcherType#ERROR} dispatch
* is detected and an error page needs to be generated by calling {@link HttpServletResponse#sendError(int, String)} with the appropriate code and reason,
* which are taken from {@link HttpServletRequest#getAttribute(String)} for {@link RequestDispatcher#ERROR_STATUS_CODE} and {@link RequestDispatcher#ERROR_MESSAGE}
* @see ErrorDispatchHandler for a convenience class that calls this method.
* @param target
* The target of the request - either a URI or a name.
* @param baseRequest
* The original unwrapped request object.
* @param request
* The request either as the {@link Request} object or a wrapper of that request. The
* {@link HttpConnection#getCurrentConnection()}.{@link HttpConnection#getHttpChannel() getHttpChannel()}.{@link HttpChannel#getRequest() getRequest()}
* method can be used access the Request object if required.
* @param response
* The response as the {@link Response} object or a wrapper of that request. The
* {@link HttpConnection#getCurrentConnection()}.{@link HttpConnection#getHttpChannel() getHttpChannel()}.{@link HttpChannel#getResponse() getResponse()}
* method can be used access the Response object if required.
* @throws IOException
* if unable to handle the request or response processing
* @throws ServletException
* if unable to handle the request or response due to underlying servlet issue
*/
protected void doError(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
{
Object o = request.getAttribute(RequestDispatcher.ERROR_STATUS_CODE);
int code = (o instanceof Integer)?((Integer)o).intValue():(o!=null?Integer.parseInt(o.toString()):500);
o = request.getAttribute(RequestDispatcher.ERROR_MESSAGE);
String reason = o!=null?o.toString():null;
response.sendError(code,reason);
}
/*
* @see org.eclipse.thread.LifeCycle#start()
*/
@Override
protected void doStart() throws Exception
{
if (LOG.isDebugEnabled())
LOG.debug("starting {}",this);
if (_server==null)
LOG.warn("No Server set for {}",this);
super.doStart();
}
/*
* @see org.eclipse.thread.LifeCycle#stop()
*/
@Override
protected void doStop() throws Exception
{
if (LOG.isDebugEnabled())
LOG.debug("stopping {}",this);
super.doStop();
}
@Override
public void setServer(Server server)
{
if (_server==server)
return;
if (isStarted())
throw new IllegalStateException(STARTED);
_server=server;
}
@Override
public Server getServer()
{
return _server;
}
@Override
public void destroy()
{
if (!isStopped())
throw new IllegalStateException("!STOPPED");
super.destroy();
}
/**
* An extension of AbstractHandler that handles {@link DispatcherType#ERROR} dispatches.
*
* {@link DispatcherType#ERROR} dispatches are handled by calling the {@link #doError(String, Request, HttpServletRequest, HttpServletResponse)}
* method. All other dispatches are passed to the abstract {@link #doNonErrorHandle(String, Request, HttpServletRequest, HttpServletResponse)}
* method, which should be implemented with specific handler behavior
*
*/
public static abstract class ErrorDispatchHandler extends AbstractHandler
{
@Override
public final void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException
{
if (baseRequest.getDispatcherType()==DispatcherType.ERROR)
doError(target,baseRequest,request,response);
else
doNonErrorHandle(target,baseRequest,request,response);
}
/**
* Called by {@link #handle(String, Request, HttpServletRequest, HttpServletResponse)}
* for all non-{@link DispatcherType#ERROR} dispatches.
* @param target
* The target of the request - either a URI or a name.
* @param baseRequest
* The original unwrapped request object.
* @param request
* The request either as the {@link Request} object or a wrapper of that request. The
* {@link HttpConnection#getCurrentConnection()}.{@link HttpConnection#getHttpChannel() getHttpChannel()}.{@link HttpChannel#getRequest() getRequest()}
* method can be used access the Request object if required.
* @param response
* The response as the {@link Response} object or a wrapper of that request. The
* {@link HttpConnection#getCurrentConnection()}.{@link HttpConnection#getHttpChannel() getHttpChannel()}.{@link HttpChannel#getResponse() getResponse()}
* method can be used access the Response object if required.
* @throws IOException
* if unable to handle the request or response processing
* @throws ServletException
* if unable to handle the request or response due to underlying servlet issue
*/
protected abstract void doNonErrorHandle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException;
}
}