ClusterGraphObserver.h

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/*
 * $Revision: 2027 $
 * 
 * last checkin:
 *   $Author: gutwenger $ 
 *   $Date: 2010-09-01 11:55:17 +0200 (Wed, 01 Sep 2010) $ 
 ***************************************************************/
 
#ifdef _MSC_VER
#pragma once
#endif

#ifndef OGDF_CLUSTER_GRAPH_OBSERVER_H
#define OGDF_CLUSTER_GRAPH_OBSERVER_H


#include <ogdf/basic/List.h>
#include <ogdf/cluster/ClusterGraph.h>

namespace ogdf {


//----------------------------------------------------------
// GraphObserver
// abstract base class
// derived classes have to overload nodeDeleted, nodeAdded
// edgeDeleted, edgeAdded
// these functions should be called by Graph before (delete)
// and after (add) its structure
//----------------------------------------------------------
class OGDF_EXPORT ClusterGraphObserver {
    friend class OGDF_EXPORT ClusterGraph;

public:
    ClusterGraphObserver() : m_pClusterGraph(0) {} 
    
    ClusterGraphObserver(const ClusterGraph* CG) : m_pClusterGraph(CG) 
    {
        m_itCGList = CG->registerObserver(this);
    }//constructor
    
    virtual ~ClusterGraphObserver() 
    {
        if (m_pClusterGraph) m_pClusterGraph->unregisterObserver(m_itCGList);
    }//destructor

    // associates structure with different graph
    void reregister(const ClusterGraph *pCG) {
        //small speedup: check if == m_pGraph
        if (m_pClusterGraph) m_pClusterGraph->unregisterObserver(m_itCGList);
        if ((m_pClusterGraph = pCG) != 0) m_itCGList = pCG->registerObserver(this);
    }

    virtual void clusterDeleted(cluster v) = 0;
    virtual void clusterAdded(cluster v)   = 0;
    //virtual void reInit()             = 0; 
    //virtual void cleared()            = 0;//Graph cleared

    const ClusterGraph*  getGraph() const { return m_pClusterGraph;}

protected:
    const ClusterGraph* m_pClusterGraph; //underlying clustergraph
    
    //List entry in cluster graphs list of all registered observers
    ListIterator<ClusterGraphObserver*> m_itCGList;
};

}; // end of namespace

#endif