ComponentManager.h

#ifndef COMPONENTMANAGER_H
#define COMPONENTMANAGER_H

#include <iostream>
#include <list>

using std::list;

class Component
{
public:
    Component() { deleted = false; }
    virtual ~Component() {}
    virtual void update() = 0;
    virtual void draw() = 0;
    virtual void kill() { deleted = true; }
protected:
    bool deleted;

    friend class ComponentManager;
};

class ComponentManager
{
public:
    virtual ~ComponentManager() { clear(); }
    static ComponentManager &get()
    {
        static ComponentManager instance;
        return instance;
    }
    void add(Component *);
    void update();
    void draw();
    void clear();
    template <class ComponentType> int count();
    template <class ComponentType> void find();
    template <class ComponentType> ComponentType* next();
protected:
    list<Component*> components;
    list<Component*>:: iterator foundIter;
private:
    ComponentManager() {}
    ComponentManager(const ComponentManager& other);
    ComponentManager& operator=(const ComponentManager& other);
};

template <class ComponentType> int ComponentManager::count()
{
    int cnt = 0;
    for (list<Component*>::iterator i = components.begin();
        i!=components.end(); ++i)
        {
            if ( dynamic_cast<ComponentType*>(*i) != NULL )
                ++cnt;
        }
    return cnt;
}
template <class ComponentType> void ComponentManager::find()
{
    foundIter = components.begin();
}
template <class ComponentType> ComponentType* ComponentManager::next()
{
    while ( foundIter != components.end() )
    {
        ComponentType *et = dynamic_cast<ComponentType*>(*foundIter);
        ++foundIter;
        if ( et != NULL )
            return et;
    }
    return NULL;
}


#endif // COMPONENTMANAGER_H