Package com.google.common.graph

Class AbstractNetwork<N,E>

  • Type Parameters:
    N - Node parameter type
    E - Edge parameter type
    All Implemented Interfaces:
    Network<N,E>, PredecessorsFunction<N>, SuccessorsFunction<N>
    Direct Known Subclasses:
    ImmutableNetwork
    @Beta
public abstract class AbstractNetwork<N,E>
extends Object
implements Network<N,E>
    This class provides a skeletal implementation of Network. It is recommended to extend this class rather than implement Network directly.

    The methods implemented in this class should not be overridden unless the subclass admits a more efficient implementation.

    Since:
    20.0
    Author:
    James Sexton

    • Method Detail

      • degree

        public int degree(N node)
        Description copied from interface: Network
        Returns the count of node's incident edges, counting self-loops twice (equivalently, the number of times an edge touches node).

        For directed networks, this is equal to inDegree(node) + outDegree(node).

        For undirected networks, this is equal to incidentEdges(node).size() + (number of self-loops incident to node).

        If the count is greater than Integer.MAX_VALUE, returns Integer.MAX_VALUE.

        Specified by:
        degree in interface Network<N,E>

      • edgesConnecting

        public Set<E> edgesConnecting(N nodeU,
                              N nodeV)
        Description copied from interface: Network
        Returns the set of edges that each directly connect nodeU to nodeV.

        In an undirected network, this is equal to edgesConnecting(nodeV, nodeU).

        The resulting set of edges will be parallel (i.e. have equal Network.incidentNodes(Object). If this network does not allow parallel edges, the resulting set will contain at most one edge (equivalent to edgeConnecting(nodeU, nodeV).asSet()).

        Specified by:
        edgesConnecting in interface Network<N,E>

      • edgesConnecting

        public Set<E> edgesConnecting(EndpointPair<N> endpoints)
        Description copied from interface: Network
        Returns the set of edges that each directly connect endpoints (in the order, if any, specified by endpoints).

        The resulting set of edges will be parallel (i.e. have equal Network.incidentNodes(Object). If this network does not allow parallel edges, the resulting set will contain at most one edge (equivalent to edgeConnecting(endpoints).asSet()).

        If this network is directed, endpoints must be ordered.

        Specified by:
        edgesConnecting in interface Network<N,E>

      • edgeConnecting

        public Optional<E> edgeConnecting(N nodeU,
                                  N nodeV)
        Description copied from interface: Network
        Returns the single edge that directly connects nodeU to nodeV, if one is present, or Optional.empty() if no such edge exists.

        In an undirected network, this is equal to edgeConnecting(nodeV, nodeU).

        Specified by:
        edgeConnecting in interface Network<N,E>

      • edgeConnecting

        public Optional<E> edgeConnecting(EndpointPair<N> endpoints)
        Description copied from interface: Network
        Returns the single edge that directly connects endpoints (in the order, if any, specified by endpoints), if one is present, or Optional.empty() if no such edge exists.

        If this graph is directed, the endpoints must be ordered.

        Specified by:
        edgeConnecting in interface Network<N,E>

      • edgeConnectingOrNull

        public @Nullable E edgeConnectingOrNull(N nodeU,
                                        N nodeV)
        Description copied from interface: Network
        Returns the single edge that directly connects nodeU to nodeV, if one is present, or null if no such edge exists.

        In an undirected network, this is equal to edgeConnectingOrNull(nodeV, nodeU).

        Specified by:
        edgeConnectingOrNull in interface Network<N,E>

      • edgeConnectingOrNull

        public @Nullable E edgeConnectingOrNull(EndpointPair<N> endpoints)
        Description copied from interface: Network
        Returns the single edge that directly connects endpoints (in the order, if any, specified by endpoints), if one is present, or null if no such edge exists.

        If this graph is directed, the endpoints must be ordered.

        Specified by:
        edgeConnectingOrNull in interface Network<N,E>

      • hasEdgeConnecting

        public boolean hasEdgeConnecting(N nodeU,
                                 N nodeV)
        Description copied from interface: Network
        Returns true if there is an edge that directly connects nodeU to nodeV. This is equivalent to nodes().contains(nodeU) && successors(nodeU).contains(nodeV), and to edgeConnectingOrNull(nodeU, nodeV) != null.

        In an undirected graph, this is equal to hasEdgeConnecting(nodeV, nodeU).

        Specified by:
        hasEdgeConnecting in interface Network<N,E>

      • validateEndpoints

        protected final void validateEndpoints(EndpointPair<?> endpoints)
        Throws an IllegalArgumentException if the ordering of endpoints is not compatible with the directionality of this graph.

      • equals

        public final boolean equals(@Nullable Object obj)
        Description copied from class: java.lang.Object
        Indicates whether some other object is "equal to" this one.

        The equals method implements an equivalence relation on non-null object references:

        • It is reflexive: for any non-null reference value x, x.equals(x) should return true.
        • It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
        • It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
        • It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
        • For any non-null reference value x, x.equals(null) should return false.

        The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

        Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

        Specified by:
        equals in interface Network<N,E>
        Overrides:
        equals in class Object
        Parameters:
        obj - the reference object with which to compare.
        Returns:
        true if this object is the same as the obj argument; false otherwise.
        See Also:
        Object.hashCode(), HashMap

      • hashCode

        public final int hashCode()
        Description copied from class: java.lang.Object
        Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

        The general contract of hashCode is:

        • Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
        • If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
        • It is not required that if two objects are unequal according to the Object.equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

        As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (The hashCode may or may not be implemented as some function of an object's memory address at some point in time.)

        Specified by:
        hashCode in interface Network<N,E>
        Overrides:
        hashCode in class Object
        Returns:
        a hash code value for this object.
        See Also:
        Object.equals(java.lang.Object), System.identityHashCode(java.lang.Object)

      • toString

        public String toString()
        Returns a string representation of this network.
        Overrides:
        toString in class Object
        Returns:
        a string representation of the object.