JSinglePointer.hh

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#ifndef __JLANG__JSINGLEPOINTER__
#define __JLANG__JSINGLEPOINTER__
 
#include "JLang/JStorage.hh"
 
 
/**
 * \author mdejong
 */
 
namespace JLANG {}
namespace JPP { using namespace JLANG; }
 
namespace JLANG {
 
  /**
   * The template JSinglePointer class can be used to hold a pointer to an object.
   * The object pointed to is deleted at destruction.
   * It is possible to create a container with single pointers.
   * The first template argument refers to the data type pointed to
   * and the second to the memory management policy.
   */
  template<class JClass_t, template<class> class JMemory_t = JNew> 
  class JSinglePointer :
    public JStorage<JClass_t, JMemory_t>
  {
  public:
 
    /**
     * Default constructor.
     */
    JSinglePointer()
    {}
 
 
    /**
     * Copy constructor.
     * The ownership of the object pointed to is transferred to this single pointer.
     *
     * \param  object   single pointer
     */
    JSinglePointer(const JSinglePointer& object)
    {
      this->set(object.get());
 
      const_cast<JSinglePointer&>(object).set(NULL);
    }
 
 
    /**
     * Constructor.
     *
     * \param  p        pointer to object
     */
    JSinglePointer(JClass_t* p)
    {
      this->set(p);
    }
 
 
    /**
     * Destructor.
     */
    ~JSinglePointer()
    {
      this->reset();
    }
 
 
    /**
     * Assignment operator.
     * The object pointed to previously is deleted.
     * The ownership of the object pointed to is transferred to this single pointer.
     *
     * \param  object   single pointer
     * \return          this single pointer
     */
    JSinglePointer& operator=(const JSinglePointer& object)
    {
      if (this->get() != object.get()) {
 
        this->reset();
 
        if (object.is_valid()) {
 
          this->set(object.get());
 
          const_cast<JSinglePointer&>(object).set(NULL);
        }
      }
 
      return *this;
    }
 
 
    /**
     * Assignment operator.
     * The object pointed to previously is deleted.
     *
     * \param  p        pointer to derived class object
     * \return          this single pointer
     */
    template<class JDerived_t>
    JSinglePointer& operator=(JDerived_t* p)
    {
      this->reset(p);
 
      return *this;
    }
  };
}
 
#endif