org.eclipse.jetty.server.handler.HandlerCollection Maven / Gradle / Ivy
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//
// ========================================================================
// Copyright (c) 1995 Mort Bay Consulting Pty Ltd and others.
//
// This program and the accompanying materials are made available under the
// terms of the Eclipse Public License v. 2.0 which is available at
// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
// which is available at https://www.apache.org/licenses/LICENSE-2.0.
//
// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
// ========================================================================
//
package org.eclipse.jetty.server.handler;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
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.HandlerContainer;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.util.ArrayUtil;
import org.eclipse.jetty.util.MultiException;
import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
/**
* A collection of handlers.
*
* The default implementations calls all handlers in list order,
* regardless of the response status or exceptions. Derived implementation
* may alter the order or the conditions of calling the contained
* handlers.
*/
@ManagedObject("Handler of multiple handlers")
public class HandlerCollection extends AbstractHandlerContainer
{
private final boolean _mutableWhenRunning;
protected final AtomicReference _handlers = new AtomicReference<>();
public HandlerCollection()
{
this(false);
}
public HandlerCollection(Handler... handlers)
{
this(false, handlers);
}
public HandlerCollection(boolean mutableWhenRunning, Handler... handlers)
{
_mutableWhenRunning = mutableWhenRunning;
if (handlers.length > 0)
setHandlers(handlers);
}
/**
* @return the array of handlers.
*/
@Override
@ManagedAttribute(value = "Wrapped handlers", readonly = true)
public Handler[] getHandlers()
{
Handlers handlers = _handlers.get();
return handlers == null ? null : handlers._handlers;
}
/**
* @param handlers the array of handlers to set.
*/
public void setHandlers(Handler[] handlers)
{
if (!_mutableWhenRunning && isStarted())
throw new IllegalStateException(getState());
while (true)
{
if (updateHandlers(_handlers.get(), newHandlers(handlers)))
break;
}
}
protected Handlers newHandlers(Handler[] handlers)
{
if (handlers == null || handlers.length == 0)
return null;
return new Handlers(handlers);
}
protected boolean updateHandlers(Handlers old, Handlers handlers)
{
if (handlers != null)
{
// check for loops
for (Handler handler : handlers._handlers)
{
if (handler == this || (handler instanceof HandlerContainer &&
Arrays.asList(((HandlerContainer)handler).getChildHandlers()).contains(this)))
throw new IllegalStateException("setHandler loop");
}
// Set server
for (Handler handler : handlers._handlers)
{
if (handler.getServer() != getServer())
handler.setServer(getServer());
}
}
if (_handlers.compareAndSet(old, handlers))
{
Handler[] oldBeans = old == null ? null : old._handlers;
Handler[] newBeans = handlers == null ? null : handlers._handlers;
updateBeans(oldBeans, newBeans);
return true;
}
return false;
}
@Override
public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException
{
if (isStarted())
{
Handlers handlers = _handlers.get();
if (handlers == null)
return;
MultiException mex = null;
for (Handler handler : handlers._handlers)
{
try
{
handler.handle(target, baseRequest, request, response);
}
catch (IOException | RuntimeException e)
{
throw e;
}
catch (Exception e)
{
if (mex == null)
mex = new MultiException();
mex.add(e);
}
}
if (mex != null)
{
if (mex.size() == 1)
throw new ServletException(mex.getThrowable(0));
else
throw new ServletException(mex);
}
}
}
/**
* Adds a handler.
* This implementation adds the passed handler to the end of the existing collection of handlers.
* If the handler is already added, it is removed and readded
*/
public void addHandler(Handler handler)
{
while (true)
{
Handlers old = _handlers.get();
Handlers handlers = newHandlers(ArrayUtil.addToArray(old == null ? null : ArrayUtil.removeFromArray(old._handlers, handler), handler, Handler.class));
if (updateHandlers(old, handlers))
break;
}
}
/**
* Prepends a handler.
* This implementation adds the passed handler to the start of the existing collection of handlers.
*/
public void prependHandler(Handler handler)
{
while (true)
{
Handlers old = _handlers.get();
Handlers handlers = newHandlers(ArrayUtil.prependToArray(handler, old == null ? null : old._handlers, Handler.class));
if (updateHandlers(old, handlers))
break;
}
}
public void removeHandler(Handler handler)
{
while (true)
{
Handlers old = _handlers.get();
if (old == null || old._handlers.length == 0)
break;
Handlers handlers = newHandlers(ArrayUtil.removeFromArray(old._handlers, handler));
if (updateHandlers(old, handlers))
break;
}
}
@Override
protected void expandChildren(List list, Class byClass)
{
Handler[] handlers = getHandlers();
if (handlers != null)
for (Handler h : handlers)
{
expandHandler(h, list, byClass);
}
}
@Override
public void destroy()
{
if (!isStopped())
throw new IllegalStateException("!STOPPED");
Handler[] children = getChildHandlers();
setHandlers(null);
for (Handler child : children)
{
child.destroy();
}
super.destroy();
}
protected static class Handlers
{
private final Handler[] _handlers;
protected Handlers(Handler[] handlers)
{
this._handlers = handlers;
}
public Handler[] getHandlers()
{
return _handlers;
}
}
}