/*
* 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.tuscany.sca.core.work;
import java.security.AccessController;
import java.security.PrivilegedAction;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import org.apache.tuscany.sca.work.NotificationListener;
import org.apache.tuscany.sca.work.WorkScheduler;
import org.apache.tuscany.sca.work.WorkSchedulerException;
import commonj.work.WorkEvent;
import commonj.work.WorkListener;
import commonj.work.WorkManager;
/**
* A work scheduler implementation based on a JSR 237 work manager.
* <p/>
* <p/>
* This needs a JSR 237 work manager implementation available for scheduling work. Instances can be configured with a
* work manager implementation that is injected in. It is the responsibility of the runtime environment to make a work
* manager implementation available. For example, if the managed environment supports work manager the runtime can use
* the appropriate lookup mechanism to inject the work manager implementation. </p>
*
* @version $Rev$ $Date$
*/
public class Jsr237WorkScheduler implements WorkScheduler {
/**
* Underlying JSR-237 work manager
*/
private WorkManager jsr237WorkManager;
/**
* Initializes the JSR 237 work manager.
*
* @param jsr237WorkManager JSR 237 work manager.
*/
public Jsr237WorkScheduler() {
}
private synchronized WorkManager getWorkManager() {
if (jsr237WorkManager != null) {
return jsr237WorkManager;
}
try {
InitialContext ctx = new InitialContext();
jsr237WorkManager = (WorkManager)ctx.lookup("java:comp/env/wm/TuscanyWorkManager");
} catch (Throwable e) {
// ignore
}
if (jsr237WorkManager == null) {
jsr237WorkManager = new ThreadPoolWorkManager(10);
}
return jsr237WorkManager;
}
/**
* Schedules a unit of work for future execution. The notification listener is used to register interest in
* callbacks regarding the status of the work.
*
* @param work The unit of work that needs to be asynchronously executed.
*/
public <T extends Runnable> void scheduleWork(T work) {
scheduleWork(work, null);
}
/**
* Schedules a unit of work for future execution. The notification listener is used to register interest in
* callbacks regarding the status of the work.
*
* @param work The unit of work that needs to be asynchronously executed.
* @param listener Notification listener for callbacks.
*/
public <T extends Runnable> void scheduleWork(T work, NotificationListener<T> listener) {
if (work == null) {
throw new IllegalArgumentException("Work cannot be null");
}
Jsr237Work<T> jsr237Work = new Jsr237Work<T>(work);
try {
if (listener == null) {
getWorkManager().schedule(jsr237Work);
} else {
Jsr237WorkListener<T> jsr237WorkListener = new Jsr237WorkListener<T>(listener, work);
getWorkManager().schedule(jsr237Work, jsr237WorkListener);
}
} catch (IllegalArgumentException ex) {
if (listener != null) {
listener.workRejected(work);
} else {
throw new WorkSchedulerException(ex);
}
} catch (Exception ex) {
throw new WorkSchedulerException(ex);
}
}
public void destroy() {
if (jsr237WorkManager instanceof ThreadPoolWorkManager) {
// Allow privileged access to modify threads. Requires RuntimePermission in security
// policy.
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
((ThreadPoolWorkManager)jsr237WorkManager).destroy();
return null;
}
});
}
}
/*
* WorkListener for keeping track of work status callbacks.
*
*/
private class Jsr237WorkListener<T extends Runnable> implements WorkListener {
// Notification listener
private NotificationListener<T> listener;
// Work
private T work;
/*
* Initializes the notification listener.
*/
public Jsr237WorkListener(NotificationListener<T> listener, T work) {
this.listener = listener;
this.work = work;
}
/*
* Callback when the work is accepted.
*/
public void workAccepted(WorkEvent workEvent) {
T work = getWork();
listener.workAccepted(work);
}
/*
* Callback when the work is rejected.
*/
public void workRejected(WorkEvent workEvent) {
T work = getWork();
listener.workRejected(work);
}
/*
* Callback when the work is started.
*/
public void workStarted(WorkEvent workEvent) {
T work = getWork();
listener.workStarted(work);
}
/*
* Callback when the work is completed.
*/
public void workCompleted(WorkEvent workEvent) {
T work = getWork();
Exception exception = workEvent.getException();
if (exception != null) {
listener.workFailed(work, exception);
} else {
listener.workCompleted(work);
}
}
/*
* Gets the underlying work from the work event.
*/
private T getWork() {
return work;
}
}
}