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CdbBdbObjectVisitorImpl.hh

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#ifndef CDBBDB_OBJECT_VISITOR_IMPL_HH
#define CDBBDB_OBJECT_VISITOR_IMPL_HH

// File and Version Information:
//      $Id: CdbBdbObjectVisitorImpl.hh,v 1.2 2004/10/21 20:35:51 gapon Exp $

#include "CdbBase/CdbCommon.hh"

#include <string>

#include <oo.h>         // Objectivity/DB core API
#include <ooas.h>       // Objectivity/DB Active Schema API

// Forward declarations

class CdbBdbObjectVisitorUserAction;
class CdbBdbObjectVisitorContext;

template< class T > class CdbBdbCache;

/// This class implements the "object visiting" facility for a graph of persistent objects.
/**
  * More details...
  */
class CdbBdbObjectVisitorImpl {

    friend class CdbBdbObjectVisitor;     // who is able to create and destroy me

private:

  /// Default constructor (NOT IMPLEMENTED)
  /**
    * Implements the contract of the corresponding method of the facade class.
    *
    * @see CdbBdbObjectVisitor::CdbBdbObjectVisitor()
    */
    CdbBdbObjectVisitorImpl( );

  /// Normal constructor
  /**
    * Implements the contract of the corresponding method of the facade class.
    *
    * @see CdbBdbObjectVisitor::CdbBdbObjectVisitor()
    */
    CdbBdbObjectVisitorImpl( CdbBdbObjectVisitorUserAction* theUserAction,
                                                       bool verboseMode,
                                                       bool debugMode );

  /// Destructor
  /**
    * Implements the contract of the corresponding method of the facade class.
    *
    * @see CdbBdbObjectVisitor::~CdbBdbObjectVisitor()
    */
    virtual ~CdbBdbObjectVisitorImpl( );

  /// Visit the specified object
  /**
    * Implements the contract of the corresponding method of the facade class.
    *
    * @see CdbBdbObjectVisitor::visit()
    */
    virtual bool visit( const ooHandle(ooObj)& theInputH );

  /// Set user action
  /**
    * Implements the contract of the corresponding method of the facade class.
    *
    * @see CdbBdbObjectVisitor::setUserAction()
    */
    CdbBdbObjectVisitorUserAction* setUserAction( CdbBdbObjectVisitorUserAction* theUserAction );

private:

    /// An automatic prefix class
    /**
      * This internal helper class is meant to help with forming a proper prefix
      * string depending on the current "level" in a visited graph.
      */
    class Prefix {

    private:

      /// Default constructor (NOT IMPLEMENTED)
      /**
        * The object's default does not make any sense at all.
        */
        Prefix( );

      /// Copy constructor (NOT IMPLEMENTED)
      /**
        * Copying of these objects does not make any sense at all.
        */
        Prefix( const Prefix& );

      /// Assignment operator (NOT IMPLEMENTED)
      /**
        * Copying of these objects does not make any sense at all.
        */
        Prefix& operator=( const Prefix& );

    public:

      /// Normal constructor
      /**
        * Decrement the current level at the caller's context.
        * Set up the current prefix string at the current context.
        */
        Prefix(               int& theLevel,        /**< a reference onto the caller's context */
                const std::string& theStep = "  "   /**< the step between levels */
              );

      /// Destructor
      /**
        * Decrement the current level at the caller's context.
        */
        ~Prefix( );

      /// An explicit type conversion operator
      /**
        * Will return a pointer onto the current prefix string.
        *
        * NONE: The returned string is bound to the local object's context.
        */
        const char* c_str( ) const;

    private:

               int& _level;   // a reference onto the caller's context
        std::string _str;     // the current prefix
    };

  // Helper methods

    bool visitObject( const ooHandle(ooObj)& theH );

    bool visitObjectContents( const ooas::Class_Object& theClassObject,
                                          const Prefix& thePrefix );

private:

  // Current context

    bool _verboseMode;
    bool   _debugMode;

    CdbBdbObjectVisitorUserAction* _userAction;

  // A set to mark OID-s of input objects which were already visited.
  // The set is used for the following reasons:
  //
  // - to avoid visiting objects which have already been visited
  // - to escape from the cyclic graph problem

    CdbBdbCache< ooRef(ooObj) >* _dictionary;

  // The context object to be passed down to the user defined action

    CdbBdbObjectVisitorContext* _context;

  // Supplementary data structures

    int _level;     // the current level in a visited graph (begins with 0 for the initial object)
};

#endif  // CDBBDB_OBJECT_VISITOR_IMPL_HH

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