objectPool.hpp

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#ifndef _OBJECT_POOL_HPP_INCLUDED
#define _OBJECT_POOL_HPP_INCLUDED

#include <vector>
#include <stdexcept>

#include <boost/thread/mutex.hpp>
#include <boost/thread/condition_variable.hpp>

namespace _Wolframe {

class ObjectPoolTimeout : public std::runtime_error
{
public:
        ObjectPoolTimeout()
                :std::runtime_error( "object pool exception"){}
};

template < typename objectType >
class ObjectPool        {
public:
        ObjectPool( const unsigned to )         { m_timeout = to; }
        ObjectPool()                            { m_timeout = 0; }
        ~ObjectPool()   {
                boost::lock_guard<boost::mutex> lock( m_mutex );
                if ( !m_availList.empty() )
                        throw std::runtime_error( "ObjectPool not empty at destruction" );
        }

        std::size_t available() const           { return m_availList.size(); }

        objectType get()        {
                while( true )   {
                        boost::unique_lock<boost::mutex> lock( m_mutex );
                        if ( !m_availList.empty())      {
                                objectType obj = m_availList.back();
                                m_availList.pop_back();
                                lock.unlock();
                                return obj;
                        }
                        else    {
                                if ( m_timeout == 0 )   {
                                        while( m_availList.empty() )
                                                m_cond.wait( lock );
                                }
                                else {
                                        boost::system_time absTime = boost::get_system_time()
                                                        + boost::posix_time::seconds( m_timeout );
                                        while( m_availList.empty() )
                                                if ( ! m_cond.timed_wait( lock, absTime ))
                                                        throw ObjectPoolTimeout();
                                }
                        }
                }
                throw std::logic_error( "Logic error #1 in ObjectPool" );
        }

        void add( objectType obj )      {
                boost::lock_guard<boost::mutex> lock( m_mutex );
                m_availList.push_back( obj );
                m_cond.notify_one();
        }

        static void static_add( ObjectPool* pool, objectType obj)
        {
                pool->add( obj);
        }

        unsigned timeout() const                { return m_timeout; }
        void timeout( unsigned to )             { m_timeout = to; }
private:
        std::vector< objectType >       m_availList;    
        boost::mutex                    m_mutex;        
        boost::condition_variable       m_cond;         
        unsigned                        m_timeout;      
};

} // namespace _Wolframe

#endif // _OBJECT_POOL_HPP_INCLUDED