org.jbpm.EventCallback.java Source code

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Here is the source code for org.jbpm.EventCallback.java

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/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jbpm;

import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

import javax.transaction.Status;
import javax.transaction.Synchronization;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.jbpm.graph.def.Event;

public class EventCallback implements Serializable {

    public static final int DEFAULT_TIMEOUT = 30 * 1000;

    private static final long serialVersionUID = 1L;
    private static final Log log = LogFactory.getLog(EventCallback.class);

    private static Map<String, Semaphore> eventSemaphores = new HashMap<String, Semaphore>();

    public void processStart() {
        registerNotification(Event.EVENTTYPE_PROCESS_START);
    }

    public void processEnd() {
        registerNotification(Event.EVENTTYPE_PROCESS_END);
    }

    public void nodeEnter() {
        registerNotification(Event.EVENTTYPE_NODE_ENTER);
    }

    public void nodeLeave() {
        registerNotification(Event.EVENTTYPE_NODE_LEAVE);
    }

    public void taskCreate() {
        registerNotification(Event.EVENTTYPE_TASK_CREATE);
    }

    public void taskEnd() {
        registerNotification(Event.EVENTTYPE_TASK_END);
    }

    public void timerCreate() {
        registerNotification(Event.EVENTTYPE_TIMER_CREATE);
    }

    public void timer() {
        registerNotification(Event.EVENTTYPE_TIMER);
    }

    public void transition() {
        registerNotification(Event.EVENTTYPE_TRANSITION);
    }

    private static void registerNotification(final String event) {
        Synchronization notification = new Synchronization() {

            public void beforeCompletion() {
            }

            public void afterCompletion(int status) {
                if (status == Status.STATUS_COMMITTED) {
                    log.debug("sending '" + event + "' notification");
                    Semaphore eventSemaphore = getEventSemaphore(event);
                    eventSemaphore.release();
                }
            }

        };
        JbpmContext.getCurrentJbpmContext().getSession().getTransaction().registerSynchronization(notification);
    }

    public static void waitForEvent(String event) {
        waitForEvent(event, DEFAULT_TIMEOUT);
    }

    public static void waitForEvent(String event, long timeout) {
        log.debug("waiting for " + event);
        Semaphore eventSemaphore = getEventSemaphore(event);
        try {
            if (eventSemaphore.tryAcquire(timeout, TimeUnit.MILLISECONDS)) {
                log.debug("received '" + event + "' notification");
            } else {
                log.warn("event '" + event + "' did not occur within " + timeout + " ms");
            }
        } catch (InterruptedException e) {
            // reassert interruption
            Thread.currentThread().interrupt();
        }
    }

    private static Semaphore getEventSemaphore(String event) {
        synchronized (eventSemaphores) {
            Semaphore semaphore = eventSemaphores.get(event);
            if (semaphore == null) {
                semaphore = new Semaphore(0);
                eventSemaphores.put(event, semaphore);
            }
            return semaphore;
        }
    }

    public static void clear() {
        for (Map.Entry<String, Semaphore> entry : eventSemaphores.entrySet()) {
            int permits = entry.getValue().drainPermits();
            if (permits != 0) {
                log.warn("event '" + entry.getKey() + "' has " + permits + " outstanding notifications");
            }
        }
    }
}