source: orxonox.OLD/orxonox/trunk/src/util/fast_factory.h @ 4940

/*!
 * @file fast_factory.h
 * The ObjectManager (FastFactory) is designed, to automatically generate and remove
 * (without to much overhead) many instances of different classes.
 *
 * It is especially usefull for objects, that come only for a short time into existence,
 * and get killed after a small amount of time (like shots).
 *
 * The Creation of an Object is usually done in the Weapon Class, where one subscribes
 * a Projectile with:
 * this->bulletFactory = tFastFactory<TestBullet>::getFastFactory(CL_TEST_BULLET, "TestBullet");
 * (this might change over time).
 * Then you can at loading time initialize an amount of the class with something like:
 * this->bulletFactory->prepare(100); // creates 100 entities of TestBullet (dead ones)
 * afterwards one can just retrieve an Object form the Class with
 * this->bulletFactory->resurrect();  // this returns a BaseObject an Object of the class.
 */


#ifndef _FAST_FACTORY_H
#define _FAST_FACTORY_H

#include "base_object.h"


// FORWARD DECLARATION //
class GarbageCollector;
template<class T>
class tList;

/**
 * Creates a FastFactory to a Loadable FastFactory.
 */
//#define CREATE_FAST_FACTORY(CLASS_NAME, CLASS_ID) \
//tFastFactory<CLASS_NAME>* global_##CLASS_NAME##_FastFactory = new tFastFactory<CLASS_NAME>(#CLASS_NAME, CLASS_ID)

//! A struct, that holds Lists of Objects of a certain type.
struct FastObjectMember
  {
    BaseObject*          objectPointer;      //!< Pointer to the Object Stored in this Class (if it is the DeadList, else it is bork)

    FastObjectMember*    next;               //!< the next stored FastObjectMember. (or NULL if this is the last one stored in either the deadList or the unusedContainers)
  };

//! The FastFactory is a fast loadable object creator, and Dynamic List of dead object handler.
/**
 * The ObjectManager (FastFactory) is designed, to automatically generate and remove
 * (without to much overhead) many instances of different classes.
 *
 * FastFactory is needed to glue all the tFastFactories together.
 * It is also the general class that implements the necessary functions
 * to generate, resurrect kill and stuff...
 */
class FastFactory : public BaseObject
  {

  public:
    virtual ~FastFactory ();

    // functions to push and pop elements of this class
    BaseObject* resurrect();
    static BaseObject* resurrect(ClassID classID);
    void kill(BaseObject* object);
    static void kill(BaseObject* object, bool searchForFastFactory);

    void prepare(unsigned int count);
    // retrival functions for fast Ineraction
    //FastFactory* getFastFactory(ClassID classID);

    static void flushAll(bool hardFLUSH = false);
    void flush(bool hardFLUSH = false);

    /** @returns the first FastFactory */
    static FastFactory* getFirst()
    {
      return FastFactory::first;
    };

  protected:
    FastFactory (ClassID classID, const char* fastFactoryName = NULL);

    /** sets the Next factory in the list @param nextFactory the next factory */
    inline void setNext( FastFactory* nextFastFactory)
    {
      this->next = nextFastFactory;
    };
    /** @returns the next FastFactory */
    FastFactory* getNext() const
      {
        return this->next;
      };

    /** generates a new Object of the Class T */
    virtual void fabricate() = NULL;
    static FastFactory* searchFastFactory(ClassID classID, const char* fastFactoryName = NULL);

  private:
    static void registerFastFactory(FastFactory* fastFactory);

  protected:
    ClassID               storedClassID;        //!< The classID of the specified class.
    unsigned int          storedDeadObjects;    //!< How many dead objects are stored in this class

    FastObjectMember*     deadList;             //!< A List of all stored dead Objects of this class.
    FastObjectMember*     unusedContainers;     //!< This is a List of unused containers, that will be reused by kill.

  private:
    static FastFactory*   first;                //!< A pointer to the first FastFactory.

    FastFactory*          next;                 //!< pointer to the next FastFactory.
  };

/**
 *  a FastFactory that is able to load any kind of Object from a ClassID
 * (this is a Functor)
 */
template<class T>
class tFastFactory : public FastFactory
  {
  public:
    static tFastFactory<T>* getFastFactory(ClassID classID, const char* fastFactoryName = NULL);

  private:
    tFastFactory(ClassID classID, const char* fastFactoryName);

    virtual void fabricate();
  };

/**
 * construnts a FastFactory with
 * @param fastFactoryName the name of the FastFactory
 * @param fastFactory the ID of the class
 * @todo (can this be written in another form??)
 */
template<class T>
tFastFactory<T>::tFastFactory(ClassID classID, const char* fastFactoryName)
    : FastFactory(classID, fastFactoryName)
{}

/**
 * creates (if not existent) a Factory of Class T, and assigns some values to it
 * @param classID the ClassID to assign to this class
 * @param fastFactoryName the name to assign
 * @returns The FastFactory if existent a new Factory if not.
 */
template<class T>
tFastFactory<T>* tFastFactory<T>::getFastFactory(ClassID classID, const char* fastFactoryName)
{
  tFastFactory<T>* tmpFac = NULL;
  if (FastFactory::getFirst() != NULL)
    tmpFac = static_cast<tFastFactory<T>*>(FastFactory::getFirst()->searchFastFactory(classID, fastFactoryName));

  if (tmpFac != NULL)
    return tmpFac;
  else
    return new tFastFactory<T>(classID, fastFactoryName);
}


/**
 * fabricates an Object of Class T, that corresponds to classID.
 */
template<class T>
void tFastFactory<T>::fabricate()
{
  FastObjectMember* tmpFirstDead = new FastObjectMember;
  tmpFirstDead->objectPointer = new T();
  tmpFirstDead->next = this->deadList;
  ++this->storedDeadObjects;

  this->deadList = tmpFirstDead;
}

#endif /* _FAST_FACTORY_H */