Package com.mxgraph.analysis

Class mxGraphAnalysis

  • public class mxGraphAnalysis
extends java.lang.Object
    A singleton class that provides algorithms for graphs. Assume these variables for the following examples:
    mxICostFunction cf = mxDistanceCostFunction(); Object[] v = graph.getChildVertices(graph.getDefaultParent()); Object[] e = graph.getChildEdges(graph.getDefaultParent()); mxGraphAnalysis mga = mxGraphAnalysis.getInstance();

    Shortest Path (Dijkstra)

    For example, to find the shortest path between the first and the second selected cell in a graph use the following code:

    Object[] path = mga.getShortestPath(graph, from, to, cf, v.length, true);

    Minimum Spanning Tree

    This algorithm finds the set of edges with the minimal length that connect all vertices. This algorithm can be used as follows:
    Prim
    mga.getMinimumSpanningTree(graph, v, cf, true))
    Kruskal
    mga.getMinimumSpanningTree(graph, v, e, cf))

    Connection Components

    The union find may be used as follows to determine whether two cells are connected: boolean connected = uf.differ(vertex1, vertex2).
    See Also:
    mxICostFunction

    • Field Detail

      • instance

        protected static mxGraphAnalysis instance
        Holds the shared instance of this class.

    • Constructor Detail

      • mxGraphAnalysis

        protected mxGraphAnalysis()

    • Method Detail

      • getInstance

        public static mxGraphAnalysis getInstance()
        Returns:
        Returns the sharedInstance.

      • setInstance

        public static void setInstance​(mxGraphAnalysis instance)
        Sets the shared instance of this class.
        Parameters:
        instance - The instance to set.

      • getShortestPath

        public java.lang.Object[] getShortestPath​(mxGraph graph,
                                          java.lang.Object from,
                                          java.lang.Object to,
                                          mxICostFunction cf,
                                          int steps,
                                          boolean directed)
        Returns the shortest path between two cells or their descendants represented as an array of edges in order of traversal.
        This implementation is based on the Dijkstra algorithm.
        Parameters:
        graph - The object that defines the graph structure
        from - The source cell.
        to - The target cell (aka sink).
        cf - The cost function that defines the edge length.
        steps - The maximum number of edges to traverse.
        directed - If edge directions should be taken into account.
        Returns:
        Returns the shortest path as an alternating array of vertices and edges, starting with from and ending with to.
        See Also:
        createPriorityQueue()

      • getMinimumSpanningTree

        public java.lang.Object[] getMinimumSpanningTree​(mxGraph graph,
                                                 java.lang.Object[] v,
                                                 mxICostFunction cf,
                                                 boolean directed)
        Returns the minimum spanning tree (MST) for the graph defined by G=(E,V). The MST is defined as the set of all vertices with minimal lengths that forms no cycles in G.
        This implementation is based on the algorihm by Prim-Jarnik. It uses O(|E|+|V|log|V|) time when used with a Fibonacci heap and a graph whith a double linked-list datastructure, as is the case with the default implementation.
        Parameters:
        graph - the object that describes the graph
        v - the vertices of the graph
        cf - the cost function that defines the edge length
        Returns:
        Returns the MST as an array of edges
        See Also:
        createPriorityQueue()

      • getMinimumSpanningTree

        public java.lang.Object[] getMinimumSpanningTree​(mxGraph graph,
                                                 java.lang.Object[] v,
                                                 java.lang.Object[] e,
                                                 mxICostFunction cf)
        Returns the minimum spanning tree (MST) for the graph defined by G=(E,V). The MST is defined as the set of all vertices with minimal lenths that forms no cycles in G.
        This implementation is based on the algorihm by Kruskal. It uses O(|E|log|E|)=O(|E|log|V|) time for sorting the edges, O(|V|) create sets, O(|E|) find and O(|V|) union calls on the union find structure, thus yielding no more than O(|E|log|V|) steps. For a faster implementatin
        Parameters:
        graph - The object that contains the graph.
        v - The vertices of the graph.
        e - The edges of the graph.
        cf - The cost function that defines the edge length.
        Returns:
        Returns the MST as an array of edges.
        See Also:
        getMinimumSpanningTree(mxGraph, Object[], mxICostFunction, boolean), createUnionFind(Object[])

      • getConnectionComponents

        public mxUnionFind getConnectionComponents​(mxGraph graph,
                                           java.lang.Object[] v,
                                           java.lang.Object[] e)
        Returns a union find structure representing the connection components of G=(E,V).
        Parameters:
        graph - The object that contains the graph.
        v - The vertices of the graph.
        e - The edges of the graph.
        Returns:
        Returns the connection components in G=(E,V)
        See Also:
        createUnionFind(Object[])

      • sort

        public mxCellState[] sort​(mxCellState[] states,
                          mxICostFunction cf)
        Returns a sorted set for cells with respect to cf.
        Parameters:
        states - the cell states to sort
        cf - the cost function that defines the order
        Returns:
        Returns an ordered set of cells wrt. cf

      • sum

        public double sum​(mxCellState[] states,
                  mxICostFunction cf)
        Returns the sum of all cost for cells with respect to cf.
        Parameters:
        states - the cell states to use for the sum
        cf - the cost function that defines the costs
        Returns:
        Returns the sum of all cell cost

      • createUnionFind

        protected mxUnionFind createUnionFind​(java.lang.Object[] v)
        Hook for subclassers to provide a custom union find structure.
        Parameters:
        v - the array of all elements
        Returns:
        Returns a union find structure for v

      • createPriorityQueue

        protected mxFibonacciHeap createPriorityQueue()
        Hook for subclassers to provide a custom fibonacci heap.