source: XMLIO_V2/external/src/POCO/Foundation.save/Poco/ThreadPool.h @ 80

//
// ThreadPool.h
//
// $Id: //poco/1.3/Foundation/include/Poco/ThreadPool.h#3 $
//
// Library: Foundation
// Package: Threading
// Module:  ThreadPool
//
// Definition of the ThreadPool class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// Permission is hereby granted, free of charge, to any person or organization
// obtaining a copy of the software and accompanying documentation covered by
// this license (the "Software") to use, reproduce, display, distribute,
// execute, and transmit the Software, and to prepare derivative works of the
// Software, and to permit third-parties to whom the Software is furnished to
// do so, all subject to the following:
// 
// The copyright notices in the Software and this entire statement, including
// the above license grant, this restriction and the following disclaimer,
// must be included in all copies of the Software, in whole or in part, and
// all derivative works of the Software, unless such copies or derivative
// works are solely in the form of machine-executable object code generated by
// a source language processor.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
// SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
// FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
// ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.
//


#ifndef Foundation_ThreadPool_INCLUDED
#define Foundation_ThreadPool_INCLUDED


#include "Poco/Foundation.h"
#include "Poco/Thread.h"
#include "Poco/Mutex.h"
#include <vector>


namespace Poco {


class Runnable;
class PooledThread;


class Foundation_API ThreadPool
        /// A thread pool always keeps a number of threads running, ready
        /// to accept work.
        /// Creating and starting a threads can impose a significant runtime
        /// overhead to an application. A thread pool helps to improve
        /// the performance of an application by reducing the number
        /// of threads that have to be created (and destroyed again).
        /// Threads in a thread pool are re-used once they become
        /// available again.
        /// The thread pool always keeps a minimum number of threads
        /// running. If the demans for threads increases, additional
        /// threads are created. Once the demand for threads sinks
        /// again, no-longer used threads are stopped and removed
        /// from the pool.
{
public:
        ThreadPool(int minCapacity = 2,
                int maxCapacity = 16,
                int idleTime = 60,
                int stackSize = POCO_THREAD_STACK_SIZE);
        ThreadPool(const std::string& name,
                int minCapacity = 2,
                int maxCapacity = 16,
                int idleTime = 60,
                int stackSize = POCO_THREAD_STACK_SIZE);
                /// Creates a thread pool with minCapacity threads.
                /// If required, up to maxCapacity threads are created
                /// a NoThreadAvailableException exception is thrown.
                /// If a thread is running idle for more than idleTime seconds,
                /// and more than minCapacity threads are running, the thread
                /// is killed. Threads are created with given stack size.

        ~ThreadPool();
                /// Currently running threads will remain active
                /// until they complete. 
        
        void addCapacity(int n);
                /// Increases (or decreases, if n is negative)
                /// the maximum number of threads.

        int capacity() const;
                /// Returns the maximum capacity of threads.

        void setStackSize(int stackSize);
                /// Sets the stack size for threads.
                /// New stack size applies only for newly created threads.

        int getStackSize() const;
                /// Returns the stack size used to create new threads.

        int used() const;
                /// Returns the number of currently used threads.

        int allocated() const;
                /// Returns the number of currently allocated threads.

        int available() const;
                /// Returns the number available threads.

        void start(Runnable& target);
                /// Obtains a thread and starts the target.
                /// Throws a NoThreadAvailableException if no more
                /// threads are available.

        void start(Runnable& target, const std::string& name);
                /// Obtains a thread and starts the target.
                /// Assigns the given name to the thread.
                /// Throws a NoThreadAvailableException if no more
                /// threads are available.

        void startWithPriority(Thread::Priority priority, Runnable& target);
                /// Obtains a thread, adjusts the thread's priority, and starts the target.
                /// Throws a NoThreadAvailableException if no more
                /// threads are available.

        void startWithPriority(Thread::Priority priority, Runnable& target, const std::string& name);
                /// Obtains a thread, adjusts the thread's priority, and starts the target.
                /// Assigns the given name to the thread.
                /// Throws a NoThreadAvailableException if no more
                /// threads are available.

        void stopAll();
                /// Stops all running threads.
                /// Will also delete all thread objects.
                /// If used, this method should be the last action before
                /// the thread pool is deleted.

        void joinAll();
                /// Waits for all threads to complete.

        void collect();
                /// Stops and removes no longer used threads from the
                /// thread pool. Can be called at various times in an
                /// application's life time to help the thread pool
                /// manage its threads. Calling this method is optional,
                /// as the thread pool is also implicitly managed in
                /// calls to start(), addCapacity() and joinAll().

        static ThreadPool& defaultPool();
                /// Returns a reference to the default
                /// thread pool.

protected:
        PooledThread* getThread();
        PooledThread* createThread();

        void housekeep();

private:
        ThreadPool(const ThreadPool& pool);
        ThreadPool& operator = (const ThreadPool& pool);

        typedef std::vector<PooledThread*> ThreadVec;

        std::string _name;
        int _minCapacity;
        int _maxCapacity;
        int _idleTime;
        int _serial;
        int _age;
        int _stackSize;
        ThreadVec _threads;
        mutable FastMutex _mutex;
};


//
// inlines
//
inline void ThreadPool::setStackSize(int stackSize)
{
        _stackSize = stackSize;
}


inline int ThreadPool::getStackSize() const
{
        return _stackSize;
}


} // namespace Poco


#endif // Foundation_ThreadPool_INCLUDED