Java tutorial
/************************************************************************* * Copyright 2009-2012 Eucalyptus Systems, Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; version 3 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see http://www.gnu.org/licenses/. * * Please contact Eucalyptus Systems, Inc., 6755 Hollister Ave., Goleta * CA 93117, USA or visit http://www.eucalyptus.com/licenses/ if you need * additional information or have any questions. * * This file may incorporate work covered under the following copyright * and permission notice: * * Software License Agreement (BSD License) * * Copyright (c) 2008, Regents of the University of California * All rights reserved. * * Redistribution and use of this software in source and binary forms, * with or without modification, are permitted provided that the * following conditions are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer * in the documentation and/or other materials provided with the * distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. USERS OF THIS SOFTWARE ACKNOWLEDGE * THE POSSIBLE PRESENCE OF OTHER OPEN SOURCE LICENSED MATERIAL, * COPYRIGHTED MATERIAL OR PATENTED MATERIAL IN THIS SOFTWARE, * AND IF ANY SUCH MATERIAL IS DISCOVERED THE PARTY DISCOVERING * IT MAY INFORM DR. RICH WOLSKI AT THE UNIVERSITY OF CALIFORNIA, * SANTA BARBARA WHO WILL THEN ASCERTAIN THE MOST APPROPRIATE REMEDY, * WHICH IN THE REGENTS' DISCRETION MAY INCLUDE, WITHOUT LIMITATION, * REPLACEMENT OF THE CODE SO IDENTIFIED, LICENSING OF THE CODE SO * IDENTIFIED, OR WITHDRAWAL OF THE CODE CAPABILITY TO THE EXTENT * NEEDED TO COMPLY WITH ANY SUCH LICENSES OR RIGHTS. ************************************************************************/ package com.eucalyptus.util.async; import java.util.NoSuchElementException; import java.util.concurrent.Callable; import org.apache.log4j.Logger; import com.eucalyptus.component.ServiceConfiguration; import com.eucalyptus.context.Contexts; import com.eucalyptus.context.ServiceContext; import com.eucalyptus.empyrean.Empyrean; import com.eucalyptus.records.Logs; import com.eucalyptus.system.Threads; import com.google.common.base.Optional; import edu.ucsb.eucalyptus.msgs.BaseMessage; import edu.ucsb.eucalyptus.msgs.CallerContext; public class AsyncRequests { private static Logger LOG = Logger.getLogger(AsyncRequests.class); public static <A extends BaseMessage, B extends BaseMessage> CheckedListenableFuture<B> dispatch( final ServiceConfiguration config, final A msg) throws Exception { if (config.isVmLocal()) { final CheckedListenableFuture<B> future = Futures.newGenericeFuture(); Threads.enqueue(Empyrean.class, AsyncRequests.class, new Callable<B>() { public B call() { try { B ret = ServiceContext.send(config.getComponentId(), msg); future.set(ret); } catch (Exception ex) { future.setException(ex); } return null; } }); return future; } else { Request<A, B> req = newRequest(new MessageCallback<A, B>() { { this.setRequest(msg); } @Override public void fire(B msg) { Logs.extreme().debug(msg.toSimpleString()); } }); return req.dispatch(config); } } public static <A extends BaseMessage, B extends BaseMessage> B sendSync(ServiceConfiguration config, final A msg) throws Exception { return sendSync(config, Optional.<CallerContext>absent(), msg); } public static <A extends BaseMessage, B extends BaseMessage> B sendSyncWithCurrentIdentity( final ServiceConfiguration config, final A msg) throws Exception { return sendSync(config, Optional.of(new CallerContext(Contexts.lookup())), msg); } private static <A extends BaseMessage, B extends BaseMessage> B sendSync(final ServiceConfiguration config, final Optional<CallerContext> callerContext, final A msg) throws Exception { if (callerContext.isPresent()) { callerContext.get().apply(msg); } if (config.isVmLocal()) { return ServiceContext.send(config.getComponentId(), msg); } else { try { Request<A, B> req = newRequest(new MessageCallback<A, B>() { { this.setRequest(msg); } @Override public void fire(B msg) { Logs.extreme().debug(msg.toSimpleString()); } }); return req.sendSync(config); } catch (InterruptedException ex) { Thread.currentThread().interrupt(); throw ex; } } } /** * Calls {@link AsyncRequest#dispatch(String) dispatch} safely. * * <P>This method guarantees that either the success or failure methods of * the requests callback will be invoked.</P> * * @param request The request to dispatch * @param clusterOrPartition The cluster or partition to dispatch to * @deprecated * @see AsyncRequest#dispatch(String) */ @Deprecated public static void dispatchSafely(final Request<?, ?> request, final String clusterOrPartition) { try { request.dispatch(clusterOrPartition); } catch (NoSuchElementException e) { // request not dispatched, invoke failure handler request.getCallback().fireException(e); } } public static <A extends BaseMessage, B extends BaseMessage> Request<A, B> newRequest( final RemoteCallback<A, B> msgCallback) { return new AsyncRequest<A, B>(msgCallback) { { setRequest(msgCallback.getRequest()); } }; } }