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package com.sun.jmx.snmp.tasks;

import java.util.ArrayList;
import com.sun.jmx.snmp.tasks.Task;
import com.sun.jmx.snmp.tasks.TaskServer;

This class implements a TaskServer over a thread pool.

This API is a Sun Microsystems internal API and is subject to change without notice.

/** * This class implements a {@link com.sun.jmx.snmp.tasks.TaskServer} over * a thread pool. * <p><b>This API is a Sun Microsystems internal API and is subject * to change without notice.</b></p> **/
public class ThreadService implements TaskServer { public ThreadService(int threadNumber) { if (threadNumber <= 0) { throw new IllegalArgumentException("The thread number should bigger than zero."); } minThreads = threadNumber; threadList = new ExecutorThread[threadNumber]; priority = Thread.currentThread().getPriority(); cloader = Thread.currentThread().getContextClassLoader(); } // public methods // --------------
Submit a task to be executed. Once a task is submitted, it is guaranteed that either task.run() or task.cancel() will be called. This implementation of TaskServer uses a thread pool to execute the submitted tasks.
Params:
  • task – The task to be executed.
Throws:
/** * Submit a task to be executed. * Once a task is submitted, it is guaranteed that either * {@link com.sun.jmx.snmp.tasks.Task#run() task.run()} or * {@link com.sun.jmx.snmp.tasks.Task#cancel() task.cancel()} will be called. * This implementation of TaskServer uses a thread pool to execute * the submitted tasks. * @param task The task to be executed. * @exception IllegalArgumentException if the submitted task is null. **/
public void submitTask(Task task) throws IllegalArgumentException { submitTask((Runnable)task); }
Submit a task to be executed. This implementation of TaskServer uses a thread pool to execute the submitted tasks.
Params:
  • task – The task to be executed.
Throws:
/** * Submit a task to be executed. * This implementation of TaskServer uses a thread pool to execute * the submitted tasks. * @param task The task to be executed. * @exception IllegalArgumentException if the submitted task is null. **/
public void submitTask(Runnable task) throws IllegalArgumentException { stateCheck(); if (task == null) { throw new IllegalArgumentException("No task specified."); } synchronized(jobList) { jobList.add(jobList.size(), task); jobList.notify(); } createThread(); } public Runnable removeTask(Runnable task) { stateCheck(); Runnable removed = null; synchronized(jobList) { int lg = jobList.indexOf(task); if (lg >= 0) { removed = jobList.remove(lg); } } if (removed != null && removed instanceof Task) ((Task) removed).cancel(); return removed; } public void removeAll() { stateCheck(); final Object[] jobs; synchronized(jobList) { jobs = jobList.toArray(); jobList.clear(); } final int len = jobs.length; for (int i=0; i<len ; i++) { final Object o = jobs[i]; if (o!= null && o instanceof Task) ((Task)o).cancel(); } } // to terminate public void terminate() { if (terminated == true) { return; } terminated = true; synchronized(jobList) { jobList.notifyAll(); } removeAll(); for (int i=0; i<currThreds; i++) { try { threadList[i].interrupt(); } catch (Exception e) { // TODO } } threadList = null; } // private classes // --------------- // A thread used to execute jobs // private class ExecutorThread extends Thread { public ExecutorThread() { super(threadGroup, "ThreadService-"+counter++); setDaemon(true); // init this.setPriority(priority); this.setContextClassLoader(cloader); idle++; } public void run() { while(!terminated) { Runnable job = null; synchronized(jobList) { if (jobList.size() > 0) { job = jobList.remove(0); if (jobList.size() > 0) { jobList.notify(); } } else { try { jobList.wait(); } catch (InterruptedException ie) { // terminated ? } finally { } continue; } } if (job != null) { try { idle--; job.run(); } catch (Exception e) { // TODO e.printStackTrace(); } finally { idle++; } } // re-init this.setPriority(priority); this.interrupted(); this.setContextClassLoader(cloader); } } } // private methods private void stateCheck() throws IllegalStateException { if (terminated) { throw new IllegalStateException("The thread service has been terminated."); } } private void createThread() { if (idle < 1) { synchronized(threadList) { if (jobList.size() > 0 && currThreds < minThreads) { ExecutorThread et = new ExecutorThread(); et.start(); threadList[currThreds++] = et; } } } } // protected or private variables // ------------------------------ private ArrayList<Runnable> jobList = new ArrayList<Runnable>(0); private ExecutorThread[] threadList; private int minThreads = 1; private int currThreds = 0; private int idle = 0; private boolean terminated = false; private int priority; private ThreadGroup threadGroup = new ThreadGroup("ThreadService"); private ClassLoader cloader; private static long counter = 0; private int addedJobs = 1; private int doneJobs = 1; }