Dave Hoover
02899d1083
git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@6407 542714f4-19e9-0310-aa3c-eee0fc999fb1
102 lines
3.4 KiB
Java
102 lines
3.4 KiB
Java
//
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// $Id$
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//
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// Narya library - tools for developing networked games
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// Copyright (C) 2002-2011 Three Rings Design, Inc., All Rights Reserved
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// http://code.google.com/p/narya/
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//
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// This library is free software; you can redistribute it and/or modify it
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// under the terms of the GNU Lesser General Public License as published
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// by the Free Software Foundation; either version 2.1 of the License, or
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// (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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package com.threerings.web.server;
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import java.util.concurrent.Callable;
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import com.samskivert.servlet.util.ServiceWaiter;
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import com.samskivert.util.RunQueue;
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import com.threerings.presents.data.InvocationCodes;
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import com.threerings.presents.server.InvocationException;
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import com.threerings.web.gwt.ServiceException;
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import static com.threerings.admin.Log.log;
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/**
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* Used to bridge the gap between synchronous servlets and our asynchronous
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* game server architecture.
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*
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* <p> We don't want to use service waiters as a permanent solution, as that
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* will result in a zillion servlet threads hanging around waiting for results
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* all over the goddamned place. Instead we want to rearchitect Jetty to
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* support asynchronous servlets that give up their thread when they need to
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* block and grab a new thread out of the pool when they're ready to go
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* again. This is a tall order, but I think they might be working on something
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* like this for Jetty 6.0.
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*/
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public class ServletWaiter<T> extends ServiceWaiter<T>
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{
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public ServletWaiter (String ident)
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{
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_ident = ident;
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}
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/**
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* Waits for our asynchronous result and returns it if all is well. If
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* anything goes wrong (a timeout or a asynchronous call failure) the
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* exception is logged and a {@link ServiceException} is thrown.
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*/
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public T waitForResult ()
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throws ServiceException
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{
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try {
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if (waitForResponse()) {
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return getArgument();
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} else {
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throw getError();
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}
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} catch (InvocationException ie) {
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// pass these through without a fuss
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throw new ServiceException(ie.getMessage());
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} catch (Exception e) {
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log.warning(_ident + " failed.", e);
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throw new ServiceException(InvocationCodes.E_INTERNAL_ERROR);
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}
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}
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/**
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* Posts a result getter to be executed on the run queue thread and blocks waiting for the
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* result.
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*/
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public static <T> T queueAndWait (
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RunQueue runq, final String name, final Callable<T> action)
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throws ServiceException
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{
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final ServletWaiter<T> waiter = new ServletWaiter<T>(name);
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runq.postRunnable(new Runnable() {
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public void run () {
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try {
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waiter.postSuccess(action.call());
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} catch (final Exception e) {
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waiter.postFailure(e);
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}
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}
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});
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return waiter.waitForResult();
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}
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protected String _ident;
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}
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