JReference.hh

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#ifndef __JLANG__JREFERENCE__
#define __JLANG__JREFERENCE__

#include "JLang/JPointer.hh"
#include "JLang/JException.hh"


/**
 * \author mdejong
 */

namespace JLANG {}
namespace JPP { using namespace JLANG; }

namespace JLANG {

  /**
   * The template JReference class can be used to reference an object.
   */
  template<class JClass_t>
  class JReference {
  public:
    /**
     * Constructor
     *
     * \param  object          object
     */
    JReference(JClass_t& object) :
      __object(object)
    {}


    /**
     * Get reference to object.
     *
     * \return                 reference to object
     */
    const JClass_t& getReference() const
    {
      return __object;
    }


    /**
     * Get reference to object.
     *
     * \return                 reference to object
     */
    JClass_t& getReference()
    {
      return __object;
    }


    /**
     * Check validity of reference.
     *
     * \return                 true
     */
    bool is_valid() const
    {
      return true;
    }


    /**
     * Smart pointer.
     *
     * \return                 pointer to object
     */
    const JClass_t* operator->() const
    {
      return &__object;
    }


    /**
     * Smart pointer.
     *
     * \return                 pointer to object
     */
    JClass_t* operator->()
    {
      return &__object;
    }


    /**
     * Dereference operator.
     *
     * \return                 reference to object
     */
    const JClass_t& operator*() const
    {
      return __object;
    }


    /**
     * Dereference operator.
     *
     * \return                 reference to object
     */
    JClass_t& operator*()
    {
      return __object;
    }
    
  protected:
    JClass_t& __object;
  };


  /**
   * Template specialisation of JReference class for const data type.
   */
  template<class JClass_t>
  class JReference<const JClass_t>
  {
  public:
    /**
     * Constructor
     *
     * \param  object          object
     */
    JReference(const JClass_t& object) :
      __object(object)
    {}


    /**
     * Constructor
     *
     * \param  reference       reference
     */
    JReference(const JReference<JClass_t>& reference) :
      __object(*reference)
    {}


    /**
     * Get reference to object.
     *
     * \return                 reference to object
     */
    const JClass_t& getReference() const
    {
      return __object;
    }


    /**
     * Check validity of reference.
     *
     * \return                 true
     */
    bool is_valid() const
    {
      return true;
    }


    /**
     * Smart pointer.
     *
     * \return                 pointer to object
     */
    const JClass_t* operator->() const
    {
      return &__object;
    }


    /**
     * Dereference operator.
     *
     * \return                 reference to object
     */
    const JClass_t& operator*() const
    {
      return __object;
    }
    
  protected:
    const JClass_t& __object;
  };


  /**
   * Template specialisation of JReference class for pointer type.
   */
  template<class JClass_t>
  class JReference<JClass_t* const>
  {
  public:
    /**
     * Constructor
     *
     * \param  pointer         pointer
     */
    JReference(JClass_t* const& pointer) :
      __pointer(pointer)
    {}
    

    /**
     * Constructor
     *
     * \param  pointer         pointer object
     */
    JReference(const JPointer<JClass_t>& pointer) :
      __pointer(pointer.getReference())
    {}


    /**
     * Get reference to object.
     *
     * \return                 reference to object
     */
    const JClass_t& getReference() const
    {
      return *__pointer;
    }


    /**
     * Check validity of reference.
     *
     * \return                 true if pointer not null; else false
     */
    bool is_valid() const
    {
      return (__pointer != NULL);
    }

    
    /**
     * Smart pointer.
     *
     * \return                 pointer to object
     */
    const JClass_t* operator->() const
    {
      if (__pointer == NULL)
        throw JNullPointerException("JReference::operator->()");
      else
        return __pointer;
    }


    /**
     * Dereference operator.
     *
     * \return                 reference to object
     */
    const JClass_t& operator*() const
    {
      if (__pointer == NULL)
        throw JNullPointerException("JReference::operator*()");
      else
        return *__pointer;
    }
    
  protected:
    JClass_t* const& __pointer;
  };
}

#endif