org.jgrapht.graph

Class GraphUnion<V,E,G extends Graph<V,E>>

java.lang.Object

org.jgrapht.graph.AbstractGraph<V,E>

org.jgrapht.graph.GraphUnion<V,E,G>

Type Parameters:

V - the vertex type

E - the edge type

G - the graph type of the two graphs that are combined

All Implemented Interfaces:

Serializable, Graph<V,E>

Direct Known Subclasses:

DirectedGraphUnion, MixedGraphUnion, UndirectedGraphUnion

public class GraphUnion<V,E,G extends Graph<V,E>>
extends AbstractGraph<V,E>
implements Serializable

Read-only union of two graphs: G₁ and G₂. If G₁ = (V₁, E₁) and G₂ = (V₂, E₂) then their union G = (V, E), where V is the union of V₁ and V₂, and E is the union of E₁ and E₁.

GraphUnion implements Graph interface. GraphUnion uses WeightCombiner to choose policy for calculating edge weight.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
GraphUnion(G g1, G g2) Construct a new graph union.
GraphUnion(G g1, G g2, WeightCombiner operator) Construct a new graph union.

Method Summary

Modifier and Type	Method and Description
E	addEdge(V sourceVertex, V targetVertex) Throws UnsupportedOperationException, because GraphUnion is read-only.
boolean	addEdge(V sourceVertex, V targetVertex, E e) Throws UnsupportedOperationException, because GraphUnion is read-only.
boolean	addVertex(V v) Throws UnsupportedOperationException, because GraphUnion is read-only.
boolean	containsEdge(E e) Returns true if this graph contains the specified edge.
boolean	containsVertex(V v) Returns true if this graph contains the specified vertex.
Set<E>	edgeSet() Returns a set of the edges contained in this graph.
Set<E>	edgesOf(V vertex) Returns a set of all edges touching the specified vertex.
Set<E>	getAllEdges(V sourceVertex, V targetVertex) Returns a set of all edges connecting source vertex to target vertex if such vertices exist in this graph.
E	getEdge(V sourceVertex, V targetVertex) Returns an edge connecting source vertex to target vertex if such vertices and such edge exist in this graph.
EdgeFactory<V,E>	getEdgeFactory() Throws UnsupportedOperationException, because GraphUnion is read-only.
V	getEdgeSource(E e) Returns the source vertex of an edge.
V	getEdgeTarget(E e) Returns the target vertex of an edge.
double	getEdgeWeight(E e) Returns the weight assigned to a given edge.
G	getG1() Return G1
G	getG2() Return G2
boolean	removeEdge(E e) Throws UnsupportedOperationException, because GraphUnion is read-only.
E	removeEdge(V sourceVertex, V targetVertex) Throws UnsupportedOperationException, because GraphUnion is read-only.
boolean	removeVertex(V v) Throws UnsupportedOperationException, because GraphUnion is read-only.
Set<V>	vertexSet() Returns a set of the vertices contained in this graph.

Methods inherited from class org.jgrapht.graph.AbstractGraph

assertVertexExist, containsEdge, equals, hashCode, removeAllEdges, removeAllEdges, removeAllEdges, removeAllVertices, toString, toStringFromSets

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

GraphUnion

public GraphUnion(G g1,
                  G g2,
                  WeightCombiner operator)

Construct a new graph union.

Parameters:

g1 - the first graph

g2 - the second graph

operator - the weight combiner (policy for edge weight calculation)

GraphUnion

public GraphUnion(G g1,
                  G g2)

Construct a new graph union. The union will use the WeightCombiner.SUM weight combiner.

Parameters:

g1 - the first graph

g2 - the second graph

Method Detail

getAllEdges

public Set<E> getAllEdges(V sourceVertex,
                          V targetVertex)

Description copied from interface: Graph

Returns a set of all edges connecting source vertex to target vertex if such vertices exist in this graph. If any of the vertices does not exist or is null, returns null. If both vertices exist but no edges found, returns an empty set.

In undirected graphs, some of the returned edges may have their source and target vertices in the opposite order. In simple graphs the returned set is either singleton set or empty set.

Specified by:

getAllEdges in interface Graph<V,E>

Parameters:

sourceVertex - source vertex of the edge.

targetVertex - target vertex of the edge.

Returns:

a set of all edges connecting source vertex to target vertex.

getEdge

public E getEdge(V sourceVertex,
                 V targetVertex)

Description copied from interface: Graph

Returns an edge connecting source vertex to target vertex if such vertices and such edge exist in this graph. Otherwise returns null. If any of the specified vertices is null returns null

In undirected graphs, the returned edge may have its source and target vertices in the opposite order.

Specified by:

getEdge in interface Graph<V,E>

Parameters:

sourceVertex - source vertex of the edge.

targetVertex - target vertex of the edge.

Returns:

an edge connecting source vertex to target vertex.

getEdgeFactory

public EdgeFactory<V,E> getEdgeFactory()

Throws UnsupportedOperationException, because GraphUnion is read-only.

Specified by:

getEdgeFactory in interface Graph<V,E>

Returns:

the edge factory using which this graph creates new edges.

addEdge

public E addEdge(V sourceVertex,
                 V targetVertex)

Throws UnsupportedOperationException, because GraphUnion is read-only.

Specified by:

addEdge in interface Graph<V,E>

Parameters:

sourceVertex - source vertex of the edge.

targetVertex - target vertex of the edge.

Returns:

The newly created edge if added to the graph, otherwise null.

See Also:

Graph.getEdgeFactory()

addEdge

public boolean addEdge(V sourceVertex,
                       V targetVertex,
                       E e)

Throws UnsupportedOperationException, because GraphUnion is read-only.

Specified by:

addEdge in interface Graph<V,E>

Parameters:

sourceVertex - source vertex of the edge.

targetVertex - target vertex of the edge.

e - edge to be added to this graph.

Returns:

true if this graph did not already contain the specified edge.

See Also:

Graph.addEdge(Object, Object), Graph.getEdgeFactory()

addVertex

public boolean addVertex(V v)

Throws UnsupportedOperationException, because GraphUnion is read-only.

Specified by:

addVertex in interface Graph<V,E>

Parameters:

v - vertex to be added to this graph.

Returns:

true if this graph did not already contain the specified vertex.

containsEdge

public boolean containsEdge(E e)

Description copied from interface: Graph

Returns true if this graph contains the specified edge. More formally, returns true if and only if this graph contains an edge e2 such that e.equals(e2). If the specified edge is null returns false.

Specified by:

containsEdge in interface Graph<V,E>

Parameters:

e - edge whose presence in this graph is to be tested.

Returns:

true if this graph contains the specified edge.

containsVertex

public boolean containsVertex(V v)

Description copied from interface: Graph

Returns true if this graph contains the specified vertex. More formally, returns true if and only if this graph contains a vertex u such that u.equals(v). If the specified vertex is null returns false.

Specified by:

containsVertex in interface Graph<V,E>

Parameters:

v - vertex whose presence in this graph is to be tested.

Returns:

true if this graph contains the specified vertex.

edgeSet

public Set<E> edgeSet()

Description copied from interface: Graph

Returns a set of the edges contained in this graph. The set is backed by the graph, so changes to the graph are reflected in the set. If the graph is modified while an iteration over the set is in progress, the results of the iteration are undefined.

The graph implementation may maintain a particular set ordering (e.g. via LinkedHashSet) for deterministic iteration, but this is not required. It is the responsibility of callers who rely on this behavior to only use graph implementations which support it.

Specified by:

edgeSet in interface Graph<V,E>

Returns:

a set of the edges contained in this graph.

edgesOf

public Set<E> edgesOf(V vertex)

Description copied from interface: Graph

Returns a set of all edges touching the specified vertex. If no edges are touching the specified vertex returns an empty set.

Specified by:

edgesOf in interface Graph<V,E>

Parameters:

vertex - the vertex for which a set of touching edges is to be returned.

Returns:

a set of all edges touching the specified vertex.

removeEdge

public E removeEdge(V sourceVertex,
                    V targetVertex)

Throws UnsupportedOperationException, because GraphUnion is read-only.

Specified by:

removeEdge in interface Graph<V,E>

Parameters:

sourceVertex - source vertex of the edge.

targetVertex - target vertex of the edge.

Returns:

The removed edge, or null if no edge removed.

removeEdge

public boolean removeEdge(E e)

Throws UnsupportedOperationException, because GraphUnion is read-only.

Specified by:

removeEdge in interface Graph<V,E>

Parameters:

e - edge to be removed from this graph, if present.

Returns:

true if and only if the graph contained the specified edge.

removeVertex

public boolean removeVertex(V v)

Throws UnsupportedOperationException, because GraphUnion is read-only.

Specified by:

removeVertex in interface Graph<V,E>

Parameters:

v - vertex to be removed from this graph, if present.

Returns:

true if the graph contained the specified vertex; false otherwise.

vertexSet

public Set<V> vertexSet()

Description copied from interface: Graph

Returns a set of the vertices contained in this graph. The set is backed by the graph, so changes to the graph are reflected in the set. If the graph is modified while an iteration over the set is in progress, the results of the iteration are undefined.

The graph implementation may maintain a particular set ordering (e.g. via LinkedHashSet) for deterministic iteration, but this is not required. It is the responsibility of callers who rely on this behavior to only use graph implementations which support it.

Specified by:

vertexSet in interface Graph<V,E>

Returns:

a set view of the vertices contained in this graph.

getEdgeSource

public V getEdgeSource(E e)

Description copied from interface: Graph

Returns the source vertex of an edge. For an undirected graph, source and target are distinguishable designations (but without any mathematical meaning).

Specified by:

getEdgeSource in interface Graph<V,E>

Parameters:

e - edge of interest

Returns:

source vertex

getEdgeTarget

public V getEdgeTarget(E e)

Description copied from interface: Graph

Returns the target vertex of an edge. For an undirected graph, source and target are distinguishable designations (but without any mathematical meaning).

Specified by:

getEdgeTarget in interface Graph<V,E>

Parameters:

e - edge of interest

Returns:

target vertex

getEdgeWeight

public double getEdgeWeight(E e)

Description copied from interface: Graph

Returns the weight assigned to a given edge. Unweighted graphs return 1.0 (as defined by WeightedGraph.DEFAULT_EDGE_WEIGHT), allowing weighted-graph algorithms to apply to them where meaningful.

Specified by:

getEdgeWeight in interface Graph<V,E>

Parameters:

e - edge of interest

Returns:

edge weight

See Also:

WeightedGraph

getG1

public G getG1()

Return G₁

Returns:

G₁

getG2

public G getG2()

Return G₂

Returns:

G₂