JAbstractObjectIterator.hh

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#ifndef __JLANG__JABSTRACTOBJECTITERATOR__
#define __JLANG__JABSTRACTOBJECTITERATOR__
 
#include "JLang/JObjectIterator.hh"
 
 
/**
 * \author mdejong
 */
 
namespace JLANG {}
namespace JPP { using namespace JLANG; }
 
namespace JLANG {
 
  /**
   * Abstract object iterator.
   *
   * This class implements the JObjectIterator interface via a single interface method setObject().\n
   * An internal object is used for which the default constructor should exist.
   */
  template<class T>
  class JAbstractObjectIterator :
    public virtual JObjectIterator<T>
  {
  protected:
    /** 
     * Default constructor.
     */
    JAbstractObjectIterator() :
      has_next(false)
    {}
 
    T     object;             //!< object
    bool  has_next;           //!< status
 
  public:
 
    typedef typename JObjectIterator<T>::pointer_type  pointer_type;
 
 
    /**
     * Set object.
     *
     * \param  object     reference to object to be set
     * \return            true if set; else false
     */
    virtual bool setObject(T& object) = 0;
 
    
    /**
     * Check availability of next element.
     *
     * \return            true if the iteration has more elements; else false
     */
    virtual bool hasNext() override 
    {
      if (!has_next) {
        has_next = this->setObject(object);
      }
 
      return has_next;
    }
 
 
    /**
     * Get next element.
     *
     * \return            pointer to element
     */
    virtual const pointer_type& next() override 
    {
      if (has_next)
        ps.reset(&this->object);
      else
        ps.reset(NULL);
 
      has_next = false;
      
      return ps;
    }
 
  private:
    pointer_type ps;
  };
 
 
  /**
   * Abstract object iterator with rewinding.
   */
  template<class T>
  class JRewindableAbstractObjectIterator :
    public JRewindableObjectIterator<T>,
    public JAbstractObjectIterator<T>
  {};
 
 
  /**
   * Abstract object iterator with named access.
   */
  template<class T>
  class JAccessibleAbstractObjectIterator :
    public JAccessibleObjectIterator<T>,
    public JAbstractObjectIterator<T>
  {};
}
 
#endif