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CdbIItr.hh

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#ifndef CDB_I_ITR_HH
#define CDB_I_ITR_HH

// File and Version Information:
//      $Id: CdbIItr.hh,v 1.4 2005/07/26 00:06:25 gapon Exp $

#include "CdbBase/CdbCommon.hh"

/// The base interface for the iterator classes
/**
  * This is a template base class for the other iterators used in the project.
  * The class is parametrized by the object type to be iterated.
  */
template< typename T >
class CdbIItr {

public:

  /// This is a type of a base iterator interface
  ///
    typedef CdbIItr<T> InterfaceType;

  /// Introduce a type definition for the purpose of easier reference
  /**
    * This definition provides access to the type of the parameter used
    * for the concrete template instantiation.
    */
    typedef T ValueType;

public:

  /// Make a clone of itself
  /**
    * This method has to be implemented by subclasses. It's meant to provide
    * a clone of the iterator and return a pointer onto a new object.
    *
    * @return a pointer onto a clone
    */
    virtual CdbIItr<T>* clone( ) const = 0;

  /// The destructor
  /**
    * Making the destructor of this clas virtual reinforces the derived classes
    * also have the virtual ones.
    */
    virtual ~CdbIItr( );

  /// Reset an iterator to its initial state.
  /**
    * This will reset an iterator to the state it was before the very first
    * call to the CdbIItr::next method.
    *
    * @see CdbIItr::next
    *
    * @return the completion status
    */
    virtual CdbStatus reset( ) = 0;

  /// Advance an iterator to the next position.
  /**
    * This is the first method to be called upon the initialization of the
    * of the iterator's scope.
    *
    * @return true if the operation succeded
    */
    virtual bool next( ) = 0;

  /// Obtain the currently reffered value.
  /**
    * This operation makes only sense if the previously issued CdbIItr::next
    * operation succeded. Otherwise an undefined value will be returned.
    *
    * @see CdbIItr::next
    *
    * @return a value of the currently reffered value
    */
    virtual T value( ) = 0;

  /// Check if an iterator is valid.
  /**
    * "Valid" means that an iterator is in the right scope, is pointing onto
    * some valid element and is not past the end of the iterated sequence.
    *
    * @return true if valid
    */
    virtual bool isValid( ) = 0;
};

#ifdef     BABAR_COMP_INST
#include "CdbBase/CdbIItr.cc"
#endif  // BABAR_COMP_INST

#endif  // CDB_I_ITR_HH

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