Package org.jgrapht.graph

Class AbstractGraph<V,​E>

  • Type Parameters:
    V - the graph vertex type
    E - the graph edge type
    All Implemented Interfaces:
    Graph<V,​E>
    Direct Known Subclasses:
    AbstractBaseGraph, AsGraphUnion, AsSubgraph, GraphDelegator, MaskSubgraph
    public abstract class AbstractGraph<V,​E>
extends java.lang.Object
implements Graph<V,​E>
    A skeletal implementation of the Graph interface, to minimize the effort required to implement graph interfaces. This implementation is applicable to both: directed graphs and undirected graphs.
    Author:
    Barak Naveh
    See Also:
    Graph

    • Constructor Detail

      • AbstractGraph

        protected AbstractGraph()
        Construct a new empty graph object.

    • Method Detail

      • containsEdge

        public boolean containsEdge​(V sourceVertex,
                            V targetVertex)
        Description copied from interface: Graph
        Returns true if and only if this graph contains an edge going from the source vertex to the target vertex. In undirected graphs the same result is obtained when source and target are inverted. If any of the specified vertices does not exist in the graph, or if is null, returns false.
        Specified by:
        containsEdge in interface Graph<V,​E>
        Parameters:
        sourceVertex - source vertex of the edge.
        targetVertex - target vertex of the edge.
        Returns:
        true if this graph contains the specified edge.
        See Also:
        Graph.containsEdge(Object, Object)

      • removeAllEdges

        public boolean removeAllEdges​(java.util.Collection<? extends E> edges)
        Description copied from interface: Graph
        Removes all the edges in this graph that are also contained in the specified edge collection. After this call returns, this graph will contain no edges in common with the specified edges. This method will invoke the Graph.removeEdge(Object) method.
        Specified by:
        removeAllEdges in interface Graph<V,​E>
        Parameters:
        edges - edges to be removed from this graph.
        Returns:
        true if this graph changed as a result of the call
        See Also:
        Graph.removeAllEdges(Collection)

      • removeAllEdges

        public java.util.Set<E> removeAllEdges​(V sourceVertex,
                                       V targetVertex)
        Description copied from interface: Graph
        Removes all the edges going from the specified source vertex to the specified target vertex, and returns a set of all removed edges. Returns null if any of the specified vertices does not exist in the graph. If both vertices exist but no edge is found, returns an empty set. This method will either invoke the Graph.removeEdge(Object) method, or the Graph.removeEdge(Object, Object) method.
        Specified by:
        removeAllEdges in interface Graph<V,​E>
        Parameters:
        sourceVertex - source vertex of the edge.
        targetVertex - target vertex of the edge.
        Returns:
        the removed edges, or null if either vertex is not part of graph
        See Also:
        Graph.removeAllEdges(Object, Object)

      • removeAllVertices

        public boolean removeAllVertices​(java.util.Collection<? extends V> vertices)
        Description copied from interface: Graph
        Removes all the vertices in this graph that are also contained in the specified vertex collection. After this call returns, this graph will contain no vertices in common with the specified vertices. This method will invoke the Graph.removeVertex(Object) method.
        Specified by:
        removeAllVertices in interface Graph<V,​E>
        Parameters:
        vertices - vertices to be removed from this graph.
        Returns:
        true if this graph changed as a result of the call
        See Also:
        Graph.removeAllVertices(Collection)

      • toString

        public java.lang.String toString()
        Returns a string of the parenthesized pair (V, E) representing this G=(V,E) graph. 'V' is the string representation of the vertex set, and 'E' is the string representation of the edge set.
        Overrides:
        toString in class java.lang.Object
        Returns:
        a string representation of this graph.

      • assertVertexExist

        protected boolean assertVertexExist​(V v)
        Ensures that the specified vertex exists in this graph, or else throws exception.
        Parameters:
        v - vertex
        Returns:
        true if this assertion holds.
        Throws:
        java.lang.NullPointerException - if specified vertex is null.
        java.lang.IllegalArgumentException - if specified vertex does not exist in this graph.

      • removeAllEdges

        protected boolean removeAllEdges​(E[] edges)
        Removes all the edges in this graph that are also contained in the specified edge array. After this call returns, this graph will contain no edges in common with the specified edges. This method will invoke the Graph.removeEdge(Object) method.
        Parameters:
        edges - edges to be removed from this graph.
        Returns:
        true if this graph changed as a result of the call.
        See Also:
        Graph.removeEdge(Object), Graph.containsEdge(Object)

      • toStringFromSets

        protected java.lang.String toStringFromSets​(java.util.Collection<? extends V> vertexSet,
                                            java.util.Collection<? extends E> edgeSet,
                                            boolean directed)
        Helper for subclass implementations of toString( ).
        Parameters:
        vertexSet - the vertex set V to be printed
        edgeSet - the edge set E to be printed
        directed - true to use parens for each edge (representing directed); false to use curly braces (representing undirected)
        Returns:
        a string representation of (V,E)

      • hashCode

        public int hashCode()
        Returns a hash code value for this graph. The hash code of a graph is defined to be the sum of the hash codes of vertices and edges in the graph. It is also based on graph topology and edges weights.
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        the hash code value this graph
        See Also:
        Object.hashCode()

      • equals

        public boolean equals​(java.lang.Object obj)
        Indicates whether some other object is "equal to" this graph. Returns true if the given object is also a graph, the two graphs are instances of the same graph class, have identical vertices and edges sets with the same weights.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        obj - object to be compared for equality with this graph
        Returns:
        true if the specified object is equal to this graph
        See Also:
        Object.equals(Object)