/*
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* JBoss, Home of Professional Open Source
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* Copyright 2005, JBoss Inc., and individual contributors as indicated
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* by the @authors tag. See the copyright.txt in the distribution for a
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* full listing of individual contributors.
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*
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* This 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
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* This software 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 software; if not, write to the Free
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* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
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*/
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package org.jbpm.pvm.internal.jobexecutor;
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import java.util.Collection;
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import java.util.Date;
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import org.jbpm.api.cmd.Command;
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import org.jbpm.internal.log.Log;
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import org.jbpm.pvm.internal.cmd.CommandService;
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/** this thread is responsible for acquiring jobs in the job that need to be
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* executed and then let the JobExecutor dispatch the acquired ids to one of the
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* JobExecutorThreads in the pool. There is only one dispatcher thread per
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* JobExecutor.
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*
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* @author Tom Baeyens, Guillaume Porcher
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*/
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public class DispatcherThread extends Thread {
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private static final Log log = Log.getLog(DispatcherThread.class.getName());
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protected JobExecutor jobExecutor;
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protected volatile boolean isActive = true;
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protected boolean checkForNewJobs;
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protected int currentIdleInterval;
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protected Object semaphore = new Object();
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protected DispatcherThread(JobExecutor jobExecutor) {
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this(jobExecutor, "DispatcherThread");
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}
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protected DispatcherThread(JobExecutor jobExecutor, String name) {
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super(name);
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this.jobExecutor = jobExecutor;
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}
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public void run() {
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log.info("starting " + getName());
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currentIdleInterval = jobExecutor.getIdleMillis();
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try {
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while (isActive) {
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try {
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// checkForNewJobs is set to true in jobWasAdded() below
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checkForNewJobs = false;
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// try to acquire jobs
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Collection<Long> acquiredJobDbids = acquireJobs();
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// no exception so resetting the currentIdleInterval
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currentIdleInterval = jobExecutor.getIdleMillis();
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if ((acquiredJobDbids != null) && (!acquiredJobDbids.isEmpty())) {
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submitAcquiredJobDbids(acquiredJobDbids);
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log.debug("added jobs "+acquiredJobDbids+" to the queue");
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} else if (isActive) {
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long waitPeriod = getWaitPeriod();
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if (waitPeriod > 0) {
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synchronized (semaphore) {
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if (!checkForNewJobs) {
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log.trace(getName()+" will wait for max "+waitPeriod+"ms on "+jobExecutor);
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semaphore.wait(waitPeriod);
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log.trace(getName()+" woke up");
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} else {
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log.debug("skipped wait because new message arrived");
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}
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}
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}
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}
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} catch (InterruptedException e) {
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log.info((isActive ? "active" : "inactive") + " job dispatcher thread '" + getName() + "' got interrupted");
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} catch (Exception e) {
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// the exception doesn't have to be logged if jboss is still booting
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// this should be replaced with proper dependency configuration
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// https://jira.jboss.org/jira/browse/JBPM-2501
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if (e.getMessage().indexOf("couldn't lookup 'UserTransaction' from jndi: UserTransaction not bound: UserTransaction not bound")==-1) {
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log.error("exception in job executor thread. waiting " + currentIdleInterval + " milliseconds", e);
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}
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try {
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synchronized (semaphore) {
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semaphore.wait(currentIdleInterval);
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}
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} catch (InterruptedException e2) {
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log.trace("delay after exception got interrupted", e2);
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}
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// after an exception, the current idle interval is doubled to prevent
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// continuous exception generation when e.g. the db is unreachable
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currentIdleInterval = currentIdleInterval * 2;
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}
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}
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} finally {
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log.info(getName() + " leaves cyberspace");
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}
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}
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protected void submitAcquiredJobDbids(Collection<Long> jobDbids) {
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log.debug("submitting jobs "+jobDbids);
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jobExecutor.getThreadPool().submit(
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new JobParcel(jobExecutor.getCommandExecutor(), jobDbids));
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log.trace("jobs "+jobDbids+" were submitted");
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}
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protected Collection<Long> acquireJobs() {
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CommandService commandService = jobExecutor.getCommandExecutor();
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Command<Collection<Long>> acquireJobsCommand = jobExecutor.getAcquireJobsCommand();
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return commandService.execute(acquireJobsCommand);
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}
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protected Date getNextDueDate() {
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CommandService commandService = jobExecutor.getCommandExecutor();
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Command<Date> getNextDueDate = jobExecutor.getNextDueDateCommand();
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return commandService.execute(getNextDueDate);
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}
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protected long getWaitPeriod() {
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long interval = jobExecutor.getIdleMillis();
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Date nextDueDate = getNextDueDate();
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if (nextDueDate != null) {
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long currentTimeMillis = System.currentTimeMillis();
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long nextDueDateTime = nextDueDate.getTime();
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if (nextDueDateTime < currentTimeMillis + currentIdleInterval) {
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interval = nextDueDateTime - currentTimeMillis;
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}
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}
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if (interval < 0) {
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interval = 0;
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}
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return interval;
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}
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public void deactivate() {
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deactivate(false);
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}
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public void deactivate(boolean join) {
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if (isActive) {
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log.debug("deactivating "+getName());
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isActive = false;
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interrupt();
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if (join) {
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try {
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log.debug("joining "+getName());
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join();
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} catch (InterruptedException e) {
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log.trace("joining "+getName()+" got interrupted");
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}
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}
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} else {
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log.trace("ignoring deactivate: "+getName()+" is not active");
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}
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}
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public void jobWasAdded() {
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log.trace("notifying job executor dispatcher thread of new job");
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synchronized (semaphore) {
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checkForNewJobs = true;
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semaphore.notify();
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}
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}
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public boolean isActive() {
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return isActive;
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}
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}
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