RunnableScheduler.java |
/* * JBoss, the OpenSource J2EE webOS * * Distributable under LGPL license. * See terms of license at gnu.org. */ package org.jboss.mx.util; import java.util.Iterator; import java.util.TreeSet; /** * A runnable scheduler.<p> * * The scheduler needs to be started to do real work. To add work to the * scheduler, create a SchedulableRunnable and set the scheduler. When * the next run has passed the work is performed. * * @see SchedulableRunnable * * @author <a href="mailto:Adrian.Brock@HappeningTimes.com">Adrian Brock</a>. * @version $Revision: 1.3.6.1 $ */ public class RunnableScheduler implements Runnable { // Attributes ---------------------------------------------------- /** * The runnables to schedule */ private TreeSet runnables = new TreeSet(); /** * The thread pool used to process the runnables. */ private ThreadPool threadPool; /** * The controller thread. */ private Thread controller = null; // Static -------------------------------------------------------- // Constructors -------------------------------------------------- /** * Constructs a new runnable scheduler. */ public RunnableScheduler() { } /** * Start the scheduler */ public synchronized void start() { //log.debug("start"); if (controller != null) return; controller = new Thread(this); controller.setDaemon(true); controller.start(); } /** * Stop the scheduler */ public synchronized void stop() { //log.debug("stop"); if (controller == null) return; controller.interrupt(); controller = null; } /** * Run the scheduler */ public void run() { // Start the threadpool threadPool = new ThreadPool(); threadPool.setActive(true); try { // Do outstanding work until stopped while (true) { try { runOutstanding(); waitOutstanding(); } catch (InterruptedException weAreDone) { //log.debug("interupted"); break; } } } finally { // Stop the thread pool threadPool.setActive(false); threadPool = null; } } // Public -------------------------------------------------------- // X Implementation ---------------------------------------------- // Y Overrides --------------------------------------------------- // Protected ----------------------------------------------------- // Package ------------------------------------------------------- /** * Add a schedulable runnable * * @param runnable the runnable to add */ synchronized void add(SchedulableRunnable runnable) { runnables.add(runnable); notifyAll(); } /** * Remove a schedulable runnable * * @param runnable the runnable to add */ synchronized void remove(SchedulableRunnable runnable) { runnables.remove(runnable); } /** * Check whether the scheduler contains a runnable * * @param runnable the runnable to check * @return true when the runnable is present, false otherwise */ synchronized boolean contains(SchedulableRunnable runnable) { return runnables.contains(runnable); } // Private ------------------------------------------------------- /** * Run all outstanding runnables, they are in date order */ private synchronized void runOutstanding() { long current = System.currentTimeMillis(); Iterator iterator = runnables.iterator(); while (iterator.hasNext()) { SchedulableRunnable next = (SchedulableRunnable) iterator.next(); if (next.getNextRun() <= current) { //log.debug("runOutstanding: " + next); iterator.remove(); threadPool.run(next); } else { //log.debug("runOutstanding: break"); break; } } } /** * Wait for the next outstanding runnable */ private synchronized void waitOutstanding() throws InterruptedException { // There is nothing to run if (runnables.size() == 0) { //log.debug("waitOutstanding_1"); wait(); //log.debug("waitOutstanding_1 - wakeup"); } else { // Wait until the next runnable SchedulableRunnable next = (SchedulableRunnable) runnables.first(); long current = System.currentTimeMillis(); long wait = next.getNextRun() - current; //log.debug("waitOutstanding_2 until: " + new Date(current + wait)); if (wait > 0) wait(wait); //log.debug("waitOutstanding_2 - wakeup"); } } // Inner Classes ------------------------------------------------- }
RunnableScheduler.java |