OSWrapper::ThreadPool Class Reference

Class of thread pool pattern. More...

#include <ThreadPool.h>

Classes
class	WaitGuard
	Class to wait for the asynchronous task finished. More...

Public Member Functions
Error	start (Runnable *task, WaitGuard *waiter=0, int priority=Thread::INHERIT_PRIORITY)
	Start an asynchronous task.
Error	tryStart (Runnable *task, WaitGuard *waiter=0, int priority=Thread::INHERIT_PRIORITY)
	Try to start an asynchronous task without blocking.
Error	timedStart (Runnable *task, Timeout tmout, WaitGuard *waiter=0, int priority=Thread::INHERIT_PRIORITY)
	Start an asynchronous task with Timeout.
void	setUncaughtExceptionHandler (Thread::UncaughtExceptionHandler *handler)
	Set the UncaughtExceptionHandler for this ThreadPool.
Thread::UncaughtExceptionHandler *	getUncaughtExceptionHandler () const
	Get the UncaughtExceptionHandler for this ThreadPool.
const char *	getThreadName () const
	Get the name of threads.

Static Public Member Functions
static ThreadPool *	create (std::size_t maxThreads, std::size_t stackSize=0U, int defaultPriority=Thread::getNormalPriority(), const char *threadName="")
	Create a ThreadPool object.
static void	destroy (ThreadPool *p)
	Destroy a ThreadPool object.

Detailed Description

Class of thread pool pattern.

ThreadPool creates some threads to call tasks asynchronously. When asynchronous tasks are finished, used threads are reused later instead of destroyed. An asynchronous task needs to be a class that implements OSWrapper::Runnable interface. You can set a thread priority of the asynchronous task when you call start().

If you choose to use a WaitGuard when you call start(), you need to wait for the asynchronous task finished. After you check the task finished, you can take data from the task object without mutex.

If you choose not to use a WaitGuard when you call start(), you don't have to wait for the task finished. But the destruction of the task object must be later than the task finished. Otherwise the access violation may occur that the thread may access to the destroyed object.

Member Function Documentation

create()

ThreadPool * OSWrapper::ThreadPool::create ( std::size_t  maxThreads, std::size_t  stackSize = 0U, int  defaultPriority = Thread::getNormalPriority(), const char *  threadName = ""  )

static

Create a ThreadPool object.

Parameters

maxThreads	Number of max threads that can execute concurrently
stackSize	Stack size of threads. If zero then sets default stack size of RTOS.
defaultPriority	First, the thread priority is defaultPriority when the threads are created. Then the priority is changed by the parameter of start() when an asynchronous task is started. After the asynchronous task finishes, the priority returns to defaultPriority.
threadName	Name of threads. Threads are named the same name.

Returns

If this method succeeds then returns a pointer of ThreadPool object, else returns null pointer

destroy()

void OSWrapper::ThreadPool::destroy ( ThreadPool *  p )

static

Destroy a ThreadPool object.

This method waits for all of the asynchronous tasks finished and destroys all of the threads.

Parameters

p	Pointer of ThreadPool object created by ThreadPool::create()

Note

If p is null pointer, do nothing.

getThreadName()

const char * OSWrapper::ThreadPool::getThreadName

(

)

const

Get the name of threads.

Returns

The name of threads

getUncaughtExceptionHandler()

Thread::UncaughtExceptionHandler * OSWrapper::ThreadPool::getUncaughtExceptionHandler

(

)

const

Get the UncaughtExceptionHandler for this ThreadPool.

Returns

The UncaughtExceptionHandler object

setUncaughtExceptionHandler()

void OSWrapper::ThreadPool::setUncaughtExceptionHandler

(

Thread::UncaughtExceptionHandler *

handler

)

Set the UncaughtExceptionHandler for this ThreadPool.

Parameters

handler

Pointer of UncaughtExceptionHandler object

start()

Error OSWrapper::ThreadPool::start	(	Runnable *	task,
		WaitGuard *	waiter = 0,
		int	priority = Thread::INHERIT_PRIORITY
	)

Start an asynchronous task.

Parameters

task	Asynchronous task
waiter	Pointer of variable of WaitGuard object that state is invalid. If this method succeeds, the WaitGuard object becomes valid. If you don't want to wait for the task finished, specify null pointer or omit this.
priority	Thread priority of the asynchronous task

Return values

OK	Success. A free thread has been allocated and started
InvalidParameter	task is null pointer
CalledByNonThread	Called from non thread context (interrupt handler, timer, etc)

Note

Same as timedStart(task, Timeout::FOREVER, waiter, priority)

timedStart()

Error OSWrapper::ThreadPool::timedStart	(	Runnable *	task,
		Timeout	tmout,
		WaitGuard *	waiter = 0,
		int	priority = Thread::INHERIT_PRIORITY
	)

Start an asynchronous task with Timeout.

If all thread of this ThreadPool have already started, this method blocks the current thread for the limited time until a free thread is allocated.

Parameters

task	Asynchronous task
tmout	The limited time
waiter	Pointer of variable of WaitGuard object that state is invalid. If this method succeeds, the WaitGuard object becomes valid. If you don't want to wait for the task finished, specify null pointer or omit this.
priority	Thread priority of the asynchronous task

Return values

OK	Success. A free thread has been allocated and started
InvalidParameter	task is null pointer
TimedOut	The limited time was elapsed
CalledByNonThread	Called from non thread context (interrupt handler, timer, etc)

Note

If tmout is Timeout::POLLING then this method does not block.

If tmout is Timeout::FOREVER then this method waits forever until a free thread is allocated.

tryStart()

Error OSWrapper::ThreadPool::tryStart	(	Runnable *	task,
		WaitGuard *	waiter = 0,
		int	priority = Thread::INHERIT_PRIORITY
	)

Try to start an asynchronous task without blocking.

Parameters

task	Asynchronous task
waiter	Pointer of variable of WaitGuard object that state is invalid. If this method succeeds, the WaitGuard object becomes valid. If you don't want to wait for the task finished, specify null pointer or omit this.
priority	Thread priority of the asynchronous task

Return values

OK	Success. A free thread has been allocated and started
InvalidParameter	task is null pointer
TimedOut	Failed to allocate a free thread

Note

Same as timedStart(task, Timeout::POLLING, waiter, priority)

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The documentation for this class was generated from the following files:

• mechanism/OSWrapper/ThreadPool.h
• mechanism/OSWrapper/ThreadPool.cpp