com.databasesandlife.util

Class ThreadPool

java.lang.Object

com.databasesandlife.util.ThreadPool

public class ThreadPool
extends Object

Runs a number of Runnable tasks in a number of threads (over a number of CPU cores).

Usage:

      ThreadPool pool = new ThreadPool();
      pool.setThreadNamePrefix("foo"); // optional, for debugger output, default is class name
      pool.setThreadCount(5); // optional, default is number of CPU cores available
      pool.addTask(new Runnable() { ... }); // add one or more seed tasks;
      pool.execute(); // will start threads, execute the seed tasks, and execute any tasks they create
 

In the case that any task throws an exception, this exception is thrown by the execute() method. If all tasks run to completion, the execute() method returns with no value.

The difference to an ExecutorService is:

• The processing of tasks can add additional tasks to the queue (whereas to an ExecutorService the client adds a fixed number of tasks, and they are then executed, without the executing tasks being able to add more tasks). Such functionality is mandatory for web crawlers, which, during the processing of pages, discover links which point to additional pages which require processing.
  
  
• It is impossible to forget to "shutdown" a ThreadPool and cause a leakage of threads, as is easily possible with ExecutorService. If the execute() method is never called then no threads are ever started and the object can be garbage collected normally. If the execute() method is called then that method makes sure all threads it creates are destroyed.

Author:

This source is copyright Adrian Smith and licensed under the LGPL 3.

See Also:

Project on GitHub

Constructor Summary

Constructors

Constructor and Description
ThreadPool()

Method Summary

Modifier and Type	Method and Description
void	addTask(Runnable r)
void	execute()
void	setThreadCount(int count)
void	setThreadNamePrefix(String prefix)

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ThreadPool

public ThreadPool()

Method Detail

setThreadCount

public void setThreadCount(int count)

setThreadNamePrefix

public void setThreadNamePrefix(String prefix)

addTask

public void addTask(Runnable r)

execute

public void execute()