GraphObserver.h

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#pragma once
 
#include <ogdf/basic/Graph.h>
#include <ogdf/basic/List.h>
 
namespace ogdf {
 
//
// in embedded graphs, adjacency lists are given in clockwise order.
//
 
 
 
class OGDF_EXPORT GraphObserver {
    friend class Graph;
 
public:
    GraphObserver() : m_pGraph(nullptr) { }
 
    explicit GraphObserver(const Graph* G) : m_pGraph(G) { m_itGList = G->registerStructure(this); }
 
    virtual ~GraphObserver() {
        if (m_pGraph) {
            m_pGraph->unregisterStructure(m_itGList);
        }
    }
 
    void reregister(const Graph* pG) {
        //small speedup: check if == m_pGraph
        if (m_pGraph) {
            m_pGraph->unregisterStructure(m_itGList);
        }
        if ((m_pGraph = pG) != nullptr) {
            m_itGList = pG->registerStructure(this);
        }
    }
 
    virtual void nodeDeleted(node v) = 0;
 
    virtual void nodeAdded(node v) = 0;
 
    virtual void edgeDeleted(edge e) = 0;
 
    virtual void edgeAdded(edge e) = 0;
 
    virtual void cleared() = 0;
 
    const Graph* getGraph() const { return m_pGraph; }
 
protected:
    const Graph* m_pGraph; 
    ListIterator<GraphObserver*> m_itGList; 
};
 
}