edu.uci.ics.jung.graph
Class AbstractGraph<V,E>

java.lang.Object
  edu.uci.ics.jung.graph.AbstractGraph<V,E>

All Implemented Interfaces:

Graph<V,E>, Hypergraph<V,E>

Direct Known Subclasses:

AbstractTypedGraph, SparseGraph, SparseMultigraph

public abstract class AbstractGraph<V,E>
extends Object
implements Graph<V,E>

Abstract implementation of the Graph interface. Designed to simplify implementation of new graph classes.

Author:

Joshua O'Madadhain

Constructor Summary

AbstractGraph()

Method Summary

boolean	addEdge(E edge, Collection<? extends V> vertices) Adds edge to this graph.
boolean	addEdge(E edge, Collection<? extends V> vertices, EdgeType edgeType) Adds edge to this graph with type edge_type.
boolean	addEdge(E edge, Pair<? extends V> endpoints) Adds edge to this graph with the specified endpoints, with the default edge type.
abstract boolean	addEdge(E edge, Pair<? extends V> endpoints, EdgeType edgeType) Adds edge to this graph with the specified endpoints and EdgeType.
boolean	addEdge(E e, V v1, V v2) Adds edge e to this graph such that it connects vertex v1 to v2.
boolean	addEdge(E e, V v1, V v2, EdgeType edge_type) Adds edge e to this graph such that it connects vertex v1 to v2.
int	degree(V vertex) Returns the number of edges incident to vertex.
E	findEdge(V v1, V v2) Returns an edge that connects this vertex to v.
Collection<E>	findEdgeSet(V v1, V v2) Returns all edges that connects this vertex to v.
int	getIncidentCount(E edge) Returns the number of vertices that are incident to edge.
Collection<V>	getIncidentVertices(E edge) Returns the collection of vertices in this graph which are connected to edge.
int	getNeighborCount(V vertex) Returns the number of vertices that are adjacent to vertex (that is, the number of vertices that are incident to edges in vertex's incident edge set).
V	getOpposite(V vertex, E edge) Returns the vertex at the other end of edge from vertex.
int	getPredecessorCount(V vertex) Returns the number of predecessors that vertex has in this graph.
int	getSuccessorCount(V vertex) Returns the number of successors that vertex has in this graph.
protected Pair<V>	getValidatedEndpoints(E edge, Pair<? extends V> endpoints)
int	inDegree(V vertex) Returns the number of incoming edges incident to vertex.
boolean	isIncident(V vertex, E edge) Returns true if vertex and edge are incident to each other.
boolean	isNeighbor(V v1, V v2) Returns true if v1 and v2 share an incident edge.
boolean	isPredecessor(V v1, V v2) Returns true if v1 is a predecessor of v2 in this graph.
boolean	isSuccessor(V v1, V v2) Returns true if v1 is a successor of v2 in this graph.
int	outDegree(V vertex) Returns the number of outgoing edges incident to vertex.
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface edu.uci.ics.jung.graph.Graph

getDest, getEndpoints, getInEdges, getOutEdges, getPredecessors, getSource, getSuccessors, isDest, isSource

Methods inherited from interface edu.uci.ics.jung.graph.Hypergraph

addVertex, containsEdge, containsVertex, getDefaultEdgeType, getEdgeCount, getEdgeCount, getEdges, getEdges, getEdgeType, getIncidentEdges, getNeighbors, getVertexCount, getVertices, removeEdge, removeVertex

Constructor Detail

AbstractGraph

public AbstractGraph()

Method Detail

addEdge

public boolean addEdge(E edge,
                       Collection<? extends V> vertices)

Description copied from interface: Hypergraph

Adds edge to this graph. Fails under the following circumstances:

• edge is already an element of the graph
• either edge or vertices is null
• vertices has the wrong number of vertices for the graph type
• vertices are already connected by another edge in this graph, and this graph does not accept parallel edges

Specified by:

addEdge in interface Hypergraph<V,E>

Returns:

true if the add is successful, and false otherwise

addEdge

public boolean addEdge(E edge,
                       Collection<? extends V> vertices,
                       EdgeType edgeType)

Description copied from interface: Hypergraph

Adds edge to this graph with type edge_type. Fails under the following circumstances:

• edge is already an element of the graph
• either edge or vertices is null
• vertices has the wrong number of vertices for the graph type
• vertices are already connected by another edge in this graph, and this graph does not accept parallel edges
• edge_type is not legal for this graph

Specified by:

addEdge in interface Hypergraph<V,E>

Returns:

true if the add is successful, and false otherwise

addEdge

public boolean addEdge(E e,
                       V v1,
                       V v2)

Description copied from interface: Graph

Adds edge e to this graph such that it connects vertex v1 to v2. Equivalent to addEdge(e, new Pair(v1, v2)). If this graph does not contain v1, v2, or both, implementations may choose to either silently add the vertices to the graph or throw an IllegalArgumentException. If this graph assigns edge types to its edges, the edge type of e will be the default for this graph. See Hypergraph.addEdge() for a listing of possible reasons for failure.

Specified by:

addEdge in interface Graph<V,E>

Parameters:

e - the edge to be added

v1 - the first vertex to be connected

v2 - the second vertex to be connected

Returns:

true if the add is successful, false otherwise

See Also:

Hypergraph.addEdge(Object, Collection), Graph.addEdge(Object, Object, Object, EdgeType)

addEdge

public boolean addEdge(E e,
                       V v1,
                       V v2,
                       EdgeType edge_type)

Description copied from interface: Graph

Adds edge e to this graph such that it connects vertex v1 to v2. Equivalent to addEdge(e, new Pair(v1, v2)). If this graph does not contain v1, v2, or both, implementations may choose to either silently add the vertices to the graph or throw an IllegalArgumentException. If edgeType is not legal for this graph, this method will throw IllegalArgumentException. See Hypergraph.addEdge() for a listing of possible reasons for failure.

Specified by:

addEdge in interface Graph<V,E>

Parameters:

e - the edge to be added

v1 - the first vertex to be connected

v2 - the second vertex to be connected

edge_type - the type to be assigned to the edge

Returns:

true if the add is successful, false otherwise

See Also:

Hypergraph.addEdge(Object, Collection), Graph.addEdge(Object, Object, Object)

addEdge

public boolean addEdge(E edge,
                       Pair<? extends V> endpoints)

Adds edge to this graph with the specified endpoints, with the default edge type.

Returns:

true iff the graph was modified as a result of this call

addEdge

public abstract boolean addEdge(E edge,
                                Pair<? extends V> endpoints,
                                EdgeType edgeType)

Adds edge to this graph with the specified endpoints and EdgeType.

Returns:

true iff the graph was modified as a result of this call

getValidatedEndpoints

protected Pair<V> getValidatedEndpoints(E edge,
                                        Pair<? extends V> endpoints)

inDegree

public int inDegree(V vertex)

Description copied from interface: Graph

Returns the number of incoming edges incident to vertex. Equivalent to getInEdges(vertex).size().

Specified by:

inDegree in interface Graph<V,E>

Specified by:

inDegree in interface Hypergraph<V,E>

Parameters:

vertex - the vertex whose indegree is to be calculated

Returns:

the number of incoming edges incident to vertex

outDegree

public int outDegree(V vertex)

Description copied from interface: Graph

Returns the number of outgoing edges incident to vertex. Equivalent to getOutEdges(vertex).size().

Specified by:

outDegree in interface Graph<V,E>

Specified by:

outDegree in interface Hypergraph<V,E>

Parameters:

vertex - the vertex whose outdegree is to be calculated

Returns:

the number of outgoing edges incident to vertex

isPredecessor

public boolean isPredecessor(V v1,
                             V v2)

Description copied from interface: Graph

Returns true if v1 is a predecessor of v2 in this graph. Equivalent to v1.getPredecessors().contains(v2).

Specified by:

isPredecessor in interface Graph<V,E>

Parameters:

v1 - the first vertex to be queried

v2 - the second vertex to be queried

Returns:

true if v1 is a predecessor of v2, and false otherwise.

isSuccessor

public boolean isSuccessor(V v1,
                           V v2)

Description copied from interface: Graph

Returns true if v1 is a successor of v2 in this graph. Equivalent to v1.getSuccessors().contains(v2).

Specified by:

isSuccessor in interface Graph<V,E>

Parameters:

v1 - the first vertex to be queried

v2 - the second vertex to be queried

Returns:

true if v1 is a successor of v2, and false otherwise.

getPredecessorCount

public int getPredecessorCount(V vertex)

Description copied from interface: Graph

Returns the number of predecessors that vertex has in this graph. Equivalent to vertex.getPredecessors().size().

Specified by:

getPredecessorCount in interface Graph<V,E>

Parameters:

vertex - the vertex whose predecessor count is to be returned

Returns:

the number of predecessors that vertex has in this graph

getSuccessorCount

public int getSuccessorCount(V vertex)

Description copied from interface: Graph

Returns the number of successors that vertex has in this graph. Equivalent to vertex.getSuccessors().size().

Specified by:

getSuccessorCount in interface Graph<V,E>

Parameters:

vertex - the vertex whose successor count is to be returned

Returns:

the number of successors that vertex has in this graph

isNeighbor

public boolean isNeighbor(V v1,
                          V v2)

Description copied from interface: Hypergraph

Returns true if v1 and v2 share an incident edge. Equivalent to getNeighbors(v1).contains(v2).

Specified by:

isNeighbor in interface Hypergraph<V,E>

Parameters:

v1 - the first vertex to test

v2 - the second vertex to test

Returns:

true if v1 and v2 share an incident edge

isIncident

public boolean isIncident(V vertex,
                          E edge)

Description copied from interface: Hypergraph

Returns true if vertex and edge are incident to each other. Equivalent to getIncidentEdges(vertex).contains(edge) and to getIncidentVertices(edge).contains(vertex).

Specified by:

isIncident in interface Hypergraph<V,E>

Returns:

true if vertex and edge are incident to each other

getNeighborCount

public int getNeighborCount(V vertex)

Description copied from interface: Hypergraph

Returns the number of vertices that are adjacent to vertex (that is, the number of vertices that are incident to edges in vertex's incident edge set).

Equivalent to getNeighbors(vertex).size().

Specified by:

getNeighborCount in interface Hypergraph<V,E>

Parameters:

vertex - the vertex whose neighbor count is to be returned

Returns:

the number of neighboring vertices

degree

public int degree(V vertex)

Description copied from interface: Hypergraph

Returns the number of edges incident to vertex. Special cases of interest:

• Incident self-loops are counted once.
• If there is only one edge that connects this vertex to each of its neighbors (and vice versa), then the value returned will also be equal to the number of neighbors that this vertex has (that is, the output of getNeighborCount).
• If the graph is directed, then the value returned will be the sum of this vertex's indegree (the number of edges whose destination is this vertex) and its outdegree (the number of edges whose source is this vertex), minus the number of incident self-loops (to avoid double-counting).

Equivalent to getIncidentEdges(vertex).size().

Specified by:

degree in interface Hypergraph<V,E>

Parameters:

vertex - the vertex whose degree is to be returned

Returns:

the degree of this node

See Also:

Hypergraph.getNeighborCount(Object)

getIncidentCount

public int getIncidentCount(E edge)

Description copied from interface: Hypergraph

Returns the number of vertices that are incident to edge. For hyperedges, this can be any nonnegative integer; for edges this must be 2 (or 1 if self-loops are permitted).

Equivalent to getIncidentVertices(edge).size().

Specified by:

getIncidentCount in interface Hypergraph<V,E>

Parameters:

edge - the edge whose incident vertex count is to be returned

Returns:

the number of vertices that are incident to edge.

getOpposite

public V getOpposite(V vertex,
                     E edge)

Description copied from interface: Graph

Returns the vertex at the other end of edge from vertex. (That is, returns the vertex incident to edge which is not vertex.)

Specified by:

getOpposite in interface Graph<V,E>

Parameters:

vertex - the vertex to be queried

edge - the edge to be queried

Returns:

the vertex at the other end of edge from vertex

findEdge

public E findEdge(V v1,
                  V v2)

Description copied from interface: Hypergraph

Returns an edge that connects this vertex to v. If this edge is not uniquely defined (that is, if the graph contains more than one edge connecting v1 to v2), any of these edges may be returned. findEdgeSet(v1, v2) may be used to return all such edges. Returns null if either of the following is true:

• v2 is not connected to v1
• either v1 or v2 are not present in this graph

Note: for purposes of this method, v1 is only considered to be connected to v2 via a given directed edge e if v1 == e.getSource() && v2 == e.getDest() evaluates to true. (v1 and v2 are connected by an undirected edge u if u is incident to both v1 and v2.)

Specified by:

findEdge in interface Hypergraph<V,E>

Returns:

an edge that connects v1 to v2, or null if no such edge exists (or either vertex is not present)

See Also:

Hypergraph.findEdgeSet(Object, Object)

findEdgeSet

public Collection<E> findEdgeSet(V v1,
                                 V v2)

Description copied from interface: Hypergraph

Returns all edges that connects this vertex to v. If this edge is not uniquely defined (that is, if the graph contains more than one edge connecting v1 to v2), any of these edges may be returned. findEdgeSet(v1, v2) may be used to return all such edges. Returns null if v2 is not connected to v1.
Returns an empty collection if either v1 or v2 are not present in this graph.

Note: for purposes of this method, v1 is only considered to be connected to v2 via a given directed edge d if v1 == d.getSource() && v2 == d.getDest() evaluates to true. (v1 and v2 are connected by an undirected edge u if u is incident to both v1 and v2.)

Specified by:

findEdgeSet in interface Hypergraph<V,E>

Returns:

a collection containing all edges that connect v1 to v2, or null if either vertex is not present

See Also:

Hypergraph.findEdge(Object, Object)

getIncidentVertices

public Collection<V> getIncidentVertices(E edge)

Description copied from interface: Hypergraph

Returns the collection of vertices in this graph which are connected to edge. Note that for some graph types there are guarantees about the size of this collection (i.e., some graphs contain edges that have exactly two endpoints, which may or may not be distinct). Implementations for those graph types may provide alternate methods that provide more convenient access to the vertices.

Specified by:

getIncidentVertices in interface Hypergraph<V,E>

Parameters:

edge - the edge whose incident vertices are to be returned

Returns:

the collection of vertices which are connected to edge, or null if edge is not present

toString

public String toString()

Overrides:

toString in class Object