Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you 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.apache.ode.jbi; import java.util.Map; import java.util.concurrent.Callable; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.Executors; import java.util.concurrent.ScheduledExecutorService; import java.util.concurrent.TimeUnit; import javax.jbi.messaging.InOnly; import javax.jbi.messaging.InOut; import javax.jbi.messaging.MessagingException; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.ode.bpel.iapi.PartnerRoleMessageExchange; import org.apache.ode.bpel.iapi.MessageExchange.FailureType; /** * Asynchronous JBI service consumer */ class OdeConsumerAsync extends OdeConsumer { private static final Log __log = LogFactory.getLog(OdeConsumerAsync.class); /** * We create an executor to handle all the asynchronous invocations/timeouts. Note, we don't need a lot of threads * here, the operations are all async, using single-thread executor avoids any possible problems in concurrent * use of delivery channel. * * WARNING: Canceling tasks does not immediately release them, so we don't use the schedule-cancel pattern here. */ private ScheduledExecutorService _executor; private Map<String, Long> _mexTimeouts = new ConcurrentHashMap<String, Long>(); OdeConsumerAsync(OdeContext ode) { super(ode); _executor = Executors.newSingleThreadScheduledExecutor(); _executor.scheduleWithFixedDelay(new MEXReaper(), _responseTimeout, _responseTimeout / 10, TimeUnit.MILLISECONDS); } @Override protected void doSendOneWay(final PartnerRoleMessageExchange odeMex, final InOnly inonly) { _executor.submit(new Runnable() { public void run() { try { _outstandingExchanges.put(inonly.getExchangeId(), odeMex); _ode.getChannel().send(inonly); } catch (MessagingException e) { String errmsg = "Error sending request-only message to JBI for ODE mex " + odeMex; __log.error(errmsg, e); } } }); } @Override protected void doSendTwoWay(final PartnerRoleMessageExchange odeMex, final InOut inout) { _executor.submit(new Runnable() { public void run() { try { _outstandingExchanges.put(inout.getExchangeId(), odeMex); _mexTimeouts.put(inout.getExchangeId(), System.currentTimeMillis() + _responseTimeout); _ode.getChannel().send(inout); } catch (MessagingException e) { String errmsg = "Error sending request-only message to JBI for ODE mex " + odeMex; __log.error(errmsg, e); } } }); } protected void inOutDone(InOut inout) { _mexTimeouts.remove(inout.getExchangeId()); } private class MEXReaper implements Runnable { public void run() { long now = System.currentTimeMillis(); Object[] inouts = _mexTimeouts.keySet().toArray(); for (int i = 0; i < inouts.length; i++) { long timeout = _mexTimeouts.get(inouts[i]); if (now >= timeout) { _mexTimeouts.remove(inouts[i]); final PartnerRoleMessageExchange pmex = _outstandingExchanges.remove(inouts[i]); if (pmex == null) /* no worries, got a response. */ continue; __log.warn("Timeout on JBI message exchange " + inouts[i]); try { _ode._scheduler.execIsolatedTransaction(new Callable<Void>() { public Void call() throws Exception { pmex.replyWithFailure(FailureType.NO_RESPONSE, "Response not received after " + _responseTimeout + "ms.", null); return null; } }); } catch (Exception ex) { __log.error("Error executing transaction: ", ex); } } } } } }