/*
* Copyright (c) 1996, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package sun.misc;
/**
* The request processor allows functors (Request instances) to be created
* in arbitrary threads, and to be posted for execution in a non-restricted
* thread.
*
* @author Steven B. Byrne
*/
public class RequestProcessor implements Runnable {
private static Queue requestQueue;
private static Thread dispatcher;
/**
* Queues a Request instance for execution by the request procesor
* thread.
*/
public static void postRequest(Request req) {
lazyInitialize();
requestQueue.enqueue(req);
}
/**
* Process requests as they are queued.
*/
public void run() {
lazyInitialize();
while (true) {
try {
Object obj = requestQueue.dequeue();
if (obj instanceof Request) { // ignore bogons
Request req = (Request)obj;
try {
req.execute();
} catch (Throwable t) {
// do nothing at the moment...maybe report an error
// in the future
}
}
} catch (InterruptedException e) {
// do nothing at the present time.
}
}
}
/**
* This method initiates the request processor thread. It is safe
* to call it after the thread has been started. It provides a way for
* clients to deliberately control the context in which the request
* processor thread is created
*/
public static synchronized void startProcessing() {
if (dispatcher == null) {
dispatcher = new Thread(new RequestProcessor(), "Request Processor");
dispatcher.setPriority(Thread.NORM_PRIORITY + 2);
dispatcher.start();
}
}
/**
* This method performs lazy initialization.
*/
private static synchronized void lazyInitialize() {
if (requestQueue == null) {
requestQueue = new Queue();
}
}
}