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 * in the documentation and/or other materials provided with the
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#ifndef O3D_CORE_CROSS_ICLASS_MANAGER_H_
#define O3D_CORE_CROSS_ICLASS_MANAGER_H_

#include <vector>

#include "core/cross/service_locator.h"
#include "core/cross/object_base.h"

namespace o3d {

class ServiceLocator;

// A pointer to a function that creates an object derived from NamedObject.
typedef ObjectBase::Ref (*ObjectCreateFunc)(ServiceLocator* service_locator);

// Maintains a collection of Class objects. Allows Classes to be retreived
// by name and objects of those Classes to be created.
class IClassManager {
 public:
  static const InterfaceId kInterfaceId;

  IClassManager() {}
  virtual ~IClassManager() {}

  // Registers a new Object creation function by string so that CreateObject can
  // create this new type.
  // Paramters:
  //   class_type: Class of type as provided by ObjectBase::GetClass.
  //   function: A function that creates an object of that type.
  virtual void AddClass(const ObjectBase::Class* class_type,
                        ObjectCreateFunc function) = 0;

  // A typesafe version of AddClass. It guarantees that the creator and
  // class match. (Seems like this would be better as a macro since there would
  // be no code generation).
  template <typename T>
  void AddTypedClass() {
    AddClass(T::GetApparentClass(), T::Create);
  }

  // Removes a registered class.
  // Paramters:
  //   class_type: Class of type as provided by ObjectBase::GetClass.
  virtual void RemoveClass(const ObjectBase::Class* class_type) = 0;

  // A typesafe version of RemoveClass.
  template <typename T>
  void RemoveTypedClass() {
    RemoveClass(T::GetApparentClass());
  }

  // Returns the ObjectBase::Class for a particular class name. It only works
  // for classes that have been registered through AddClass.
  // Parameters:
  //   class_name: name of the class to look for.
  // Returns:
  //   ObjectBase::Class* for the given class name or NULL if there is no match.
  virtual const ObjectBase::Class* GetClassByClassName(
      const String& class_name) const = 0;

  // Returns true if class_name is or is derived from base_class_type. It only
  // works for classes that have been registered through AddClass.
  // Parameters:
  //   derived_class_name: Class name of derived class.
  //   base_class: Class of type to check for.
  // Returns:
  //   true if derived_class_name is or is derived from base_class.
  virtual bool ClassNameIsAClass(
      const String& derived_class_name,
      const ObjectBase::Class* base_class) const = 0;

  // Creates an Object by Class. This is an internal function. Do not use
  // directly.
  // Parameters:
  //   object_class: ObjectBase::Class* to type of class to create.
  // Returns:
  //   ObjectBase::Ref to created object.
  virtual ObjectBase::Ref CreateObjectByClass(
      const ObjectBase::Class* object_class) = 0;

  // Creates a Object based on the type. This is a type safe version of
  // CreateObjectByClass for C++.
  // Returns:
  //  pointer to new object if successful.
  template<typename T>
  typename T::Ref Create() {
    return typename T::Ref(down_cast<T*>(
        CreateObjectByClass(T::GetApparentClass()).Get()));
  }

  // Creates an Object by Class name. This is an internal function. Do not use
  // directly.
  // Parameters:
  //   type_name: Name of the Class to create.
  // Returns:
  //   ObjectBase::Ref to created object.
  virtual ObjectBase::Ref CreateObject(const String& type_name) = 0;

  // Get all the classes registered in the class manager.
  virtual std::vector<const ObjectBase::Class*>
      GetAllClasses() const = 0;

  // This class registers a class with a class manager and removes it on
  // destruction.
  template <typename T>
  class Register {
   public:
    explicit Register(ServiceLocator* service_locator)
        : class_manager_(service_locator->GetService<IClassManager>()) {
      class_manager_->AddTypedClass<T>();
    }
    ~Register() {
      class_manager_->RemoveTypedClass<T>();
    }

   private:
    IClassManager* class_manager_;
    DISALLOW_COPY_AND_ASSIGN(Register);
  };

 private:
  DISALLOW_COPY_AND_ASSIGN(IClassManager);
};

}  // namespace o3d

#endif  // O3D_CORE_CROSS_ICLASS_MANAGER_H_