ObjectPool.h

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#ifndef OBJECTPOOL_H
#define OBJECTPOOL_H

#include <vector>

//#include "queuing_mutex.h"

#include "CodeGenMacros.h"

template <class ClassType>
class ObjectPool
{
protected:

    std::vector<ClassType*> _instances;

    std::vector<ClassType*> _freeInstances;

    //mutable tbb::queuing_mutex _mutex;

    bool _deleteAllInstances;

    virtual ClassType* createInstance() = 0;

public:

    ObjectPool(unsigned int initialSize) : 
        _instances(initialSize),
        _freeInstances(initialSize),
        _deleteAllInstances(true)
    {
        //create the number of instances given in the constructor
        ClassType* instance;
        for(unsigned int i = 0; i<initialSize; ++i)
        {
            instance = new ClassType();
            _instances.push_back(instance);
            recycle(instance);
        }
    }

    ObjectPool() : _deleteAllInstances(true)
    {
    }

    virtual ~ObjectPool()
    {
        if(_deleteAllInstances)
        {
            //delete all instances, even those that are not free
            FOREACH(iter, std::vector<ClassType*>, _instances)
                delete (*iter);
        }
        else
        {
            //delete only instances currently in the pool
            FOREACH(iter, std::vector<ClassType*>, _freeInstances)
                delete (*iter);
        }
    }

    //controls whether or not all instances allocated by the pool are deleted at destruction time
    //of if only those currently in the pool are deleted
    INLINE GET(getDeleteAllInstances, bool, _deleteAllInstances)
    INLINE SET(setDeleteAllInstances, bool, _deleteAllInstances)

    virtual ClassType* getInstance()
    {
        //tbb::queuing_mutex::scoped_lock lock(_mutex);

        ClassType* ret = NULL;
        //for thread safety, add lock around this later
        if(_freeInstances.size() > 0)
        {
            ret = _freeInstances.back();
            _freeInstances.pop_back();
        }

        //if we didn't have an instance in the pool, make a new one
        if(ret == NULL)
        {
            //make a new instances and save it in the instances list
            ret = createInstance();
            _instances.push_back(ret);
        }

        return ret;
    }

    virtual void recycle(ClassType* instance)
    {
        //tbb::queuing_mutex::scoped_lock lock(_mutex);
        //for thread safety, lock around this statement
        _freeInstances.push_back(instance);
    }
};

#endif