org.sape.carbon.services.threadpool
Class DefaultThreadPoolImpl

java.lang.Object
  |
  +--org.sape.carbon.services.threadpool.DefaultThreadPoolImpl

All Implemented Interfaces:

Configurable, Destroyable, FunctionalInterface, Initializable, Startable, Suspendable, ThreadPool

public class DefaultThreadPoolImpl

extends Object

implements ThreadPool, Configurable, Initializable, Startable, Suspendable, Destroyable

This implementation of ThreadPool relys on Doug Lea's PooledExecutor thread pool thread pool implementation. The PooledExecutor is a robust, highly configurable thread pool. Some configurations do not guarantee task execution, however. See Overview of package util.concurrent for more information about the PooledExecutor and other related classes.
Copyright 2002 Sapient

Since:

carbon 2.1

Version:

$Revision: 1.8 $($Author: dvoet $ / $Date: 2003/11/20 18:49:58 $)

Author:

Douglas Voet, Nov 5, 2002

Nested Class Summary

private class

DefaultThreadPoolImpl.TaskRunner Implementation of Runnable that wraps the tasks passed into the execute method and is responsible for tracking the task as it is queued and executed.

Field Summary

private ThreadPoolConfiguration	config
private List	failedTasks
private EDU.oswego.cs.dl.util.concurrent.BoundedBuffer	taskQueue
private Component	thisComponent
private EDU.oswego.cs.dl.util.concurrent.PooledExecutor	threadPool

Constructor Summary

DefaultThreadPoolImpl()

Method Summary

void	configure(ComponentConfiguration configuration) validates the configuration object and stores it
private void	configureThreadPool() configures this.threadPool using values from this.config
void	destroy() shutsdown the pool, not waiting to complete any queued tasks
TaskInfo	execute(Runnable task, String taskName) Queues a task for execution.
TaskInfo	execute(Runnable task, String taskName, TaskCallback callback) Queues a task for execution.
List	getFailedTasks() Gets a read-only list of the tasks that failed during execution
Integer	getPoolSize() Gets the number of executions threads in the pool
Integer	getQueueSize() Gets the number of tasks currently in the queue.
void	initialize(Component thisComponent) initializes this.failedTasks and saves thisComponent for later
void	resume() Resumes executing queued tasks by starting a thread for each queued task up to the max number of threads for the pool.
void	start() Creates the thread pool object and configures it then creates the configured number of threads
void	stop() Stops the thread pool and if configured, will wait for queued tasks to execute.
void	suspend() interrupts all the threads allowing them to terminate
void	taskFailed(TaskInfo task) adds a task to the failed list

Methods inherited from class java.lang.Object

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

Field Detail

config

private ThreadPoolConfiguration config

threadPool

private EDU.oswego.cs.dl.util.concurrent.PooledExecutor threadPool

failedTasks

private List failedTasks

thisComponent

private Component thisComponent

taskQueue

private EDU.oswego.cs.dl.util.concurrent.BoundedBuffer taskQueue

Constructor Detail

DefaultThreadPoolImpl

public DefaultThreadPoolImpl()

Method Detail

execute

public TaskInfo execute(Runnable task,
                        String taskName)

Description copied from interface: ThreadPool

Queues a task for execution.

Specified by:

execute in interface ThreadPool

Parameters:

task - the Runnable object that will be executed

taskName - the name of the task, used for logging and tracking

Returns:

an object that can be used to track task status

execute

public TaskInfo execute(Runnable task,
                        String taskName,
                        TaskCallback callback)

Description copied from interface: ThreadPool

Queues a task for execution. Note that callbacks may execute on the pooled thread that executed the task.

Specified by:

execute in interface ThreadPool

Parameters:

task - the Runnable object that will be executed

taskName - the name of the task, used for logging and tracking

callback - the callback object that will be called when the task completes

Returns:

an object that can be used to track task status

getFailedTasks

public List getFailedTasks()

Description copied from interface: ThreadPool

Gets a read-only list of the tasks that failed during execution

Specified by:

getFailedTasks in interface ThreadPool

Returns:

read-only list of the tasks that failed during execution

getQueueSize

public Integer getQueueSize()

Description copied from interface: ThreadPool

Gets the number of tasks currently in the queue. This does not include the number of tasks currently executing.

Specified by:

getQueueSize in interface ThreadPool

Returns:

number of tasks in the queue

getPoolSize

public Integer getPoolSize()

Description copied from interface: ThreadPool

Gets the number of executions threads in the pool

Specified by:

getPoolSize in interface ThreadPool

Returns:

pool size

initialize

public void initialize(Component thisComponent)
                throws Exception

initializes this.failedTasks and saves thisComponent for later

Specified by:

initialize in interface Initializable

Parameters:

thisComponent - the reference to the component that this object is a part of. Store this referece within your Functional Implementation for future use.

Throws:

Exception - when there is a failure to initialize the component

configure

public void configure(ComponentConfiguration configuration)
               throws Exception

validates the configuration object and stores it

Specified by:

configure in interface Configurable

Parameters:

configuration - the configuration for this component

Throws:

Exception - indicates a unknown error

start

public void start()
           throws Exception

Creates the thread pool object and configures it then creates the configured number of threads

Specified by:

start in interface Startable

Throws:

Exception - when there is a failure to start the component

stop

public void stop()
          throws Exception

Stops the thread pool and if configured, will wait for queued tasks to execute.

Specified by:

stop in interface Startable

Throws:

Exception - when there is a failure to stop the exception

resume

public void resume()
            throws Exception

Resumes executing queued tasks by starting a thread for each queued task up to the max number of threads for the pool.

Specified by:

resume in interface Suspendable

Throws:

Exception - when there is a failure to resume the component

suspend

public void suspend()
             throws Exception

interrupts all the threads allowing them to terminate

Specified by:

suspend in interface Suspendable

Throws:

Exception - when there is a failure to suspend the component

destroy

public void destroy()
             throws Exception

shutsdown the pool, not waiting to complete any queued tasks

Specified by:

destroy in interface Destroyable

Throws:

Exception - when there is a failure in destroying the component

taskFailed

public void taskFailed(TaskInfo task)

adds a task to the failed list

configureThreadPool

private void configureThreadPool()

configures this.threadPool using values from this.config