ThreadPool (spy.jar 2.2 API)

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net.spy.concurrent
Class ThreadPool

java.lang.Object
  java.util.concurrent.AbstractExecutorService
      java.util.concurrent.ThreadPoolExecutor
          net.spy.concurrent.ThreadPool

All Implemented Interfaces:: Executor, ExecutorService

public class ThreadPool
extends ThreadPoolExecutor
extends ThreadPoolExecutor

A producer/consumer thread pool for easy parallelism.

Quick start example (assuming you want to do a million tasks, 15 at time):

 // Get a thread pool that will perform 15 tasks at a time
 ThreadPool tp=new ThreadPool("Test Pool", 15);
 // Start the thread pool
 tp.start();

 // Do the tasks in a loop, throttling to make sure all we don't
 // create too many objects that aren't ready to be used.
 for(int i=0; i<1000000; i++) {
     // Don't have more than 32 unclaimed tasks
     tp.waitForTaskCount(32);
     tp.addTask(new MyRunnableClass());
 }
 tp.waitForCompletion();

The ThreadPoolManager instance is responsible for sizing and resizing the pool. On start(), the ThreadPoolManager will size the pool to the start size configured in the ThreadPool. The manager will receive a notification after any task is added to the pool and may choose to take action at that point. Otherwise, it will sleep for a certain amount of time (one minute by default) and then begin its main loop verifying the number of idle threads satisfies the configuration.

If the number of idle threads is too low, it will create as many as is required to have the appropriate number of idle threads as long as the total number of threads will not exceed the configured maximum.

If the number of idle threads is too high, it will reduce the total number of threads by one (for each loop).

Nested Class Summary

Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor
`ThreadPoolExecutor.AbortPolicy, ThreadPoolExecutor.CallerRunsPolicy, ThreadPoolExecutor.DiscardOldestPolicy, ThreadPoolExecutor.DiscardPolicy`

Constructor Summary
`ThreadPool(String name)` Get an instance of ThreadPool with five threads and a normal priority.
`ThreadPool(String name, int n)` Get an instance of ThreadPool.
`ThreadPool(String name, int n, int max)` Get an instance of ThreadPool.
`ThreadPool(String name, int n, int max, int prio)` Get an instance of ThreadPool.
`ThreadPool(String name, int n, int max, int prio, BlockingQueue<Runnable> q)` Get an instance of ThreadPool.
`ThreadPool(String name, int n, int max, int prio, int size)` Get an instance of ThreadPool.

Method Summary
`void`	`addTask(Runnable r)` Add a task for one of the threads to execute.
`boolean`	`addTask(Runnable r, long timeout)` Add a task for one of the threads to execute.
`protected void`	`afterExecute(Runnable r, Throwable t)`
`protected void`	`beforeExecute(Thread t, Runnable r)`
`int`	`getIdleThreadCount()` Find out how many threads are idle.
`int`	`getMinTotalThreads()` Get the minimum number of threads that may exist in the thread pool at any moment.
`ThreadPoolObserver`	`getMonitor()` Get the monitor that receives notifications when a worker thread finishes a job.
`int`	`getPriority()` Get the priority that will be used for any new threads within this thread group.
`void`	`setMonitor(ThreadPoolObserver m)` Set the observer who will receive notification whenever a task is completed.
`void`	`setPriority(int p)` Set the priority to be used for any new threads within this threaad group.
`void`	`start()` Start the ThreadPool.
`String`	`toString()` String me.
`void`	`waitForCompletion()` Shut down all of the threads after all jobs are complete, and wait for all tasks to complete.
`void`	`waitForTaskCount(int num)` Wait until there are no more than num tasks in the queue.

Methods inherited from class java.util.concurrent.ThreadPoolExecutor
`awaitTermination, execute, finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getQueue, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, remove, setCorePoolSize, setKeepAliveTime, setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, shutdown, shutdownNow, terminated`

Methods inherited from class java.util.concurrent.ThreadPoolExecutor

awaitTermination, execute, finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getQueue, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, remove, setCorePoolSize, setKeepAliveTime, setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, shutdown, shutdownNow, terminated

Methods inherited from class java.util.concurrent.AbstractExecutorService
`invokeAll, invokeAll, invokeAny, invokeAny, submit, submit, submit`

Methods inherited from class java.lang.Object
`clone, equals, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Constructor Detail