Package org.jgrapht
Class Graphs
- java.lang.Object
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- org.jgrapht.Graphs
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public abstract class Graphs extends java.lang.Object
A collection of utilities to assist with graph manipulation.- Author:
- Barak Naveh
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Constructor Summary
Constructors Constructor Description Graphs()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static <V,E>
booleanaddAllEdges(Graph<? super V,? super E> destination, Graph<V,E> source, java.util.Collection<? extends E> edges)
Adds a subset of the edges of the specified source graph to the specified destination graph.static <V,E>
booleanaddAllVertices(Graph<? super V,? super E> destination, java.util.Collection<? extends V> vertices)
Adds all of the specified vertices to the destination graph.static <V,E>
EaddEdge(Graph<V,E> g, V sourceVertex, V targetVertex, double weight)
Creates a new edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.static <V,E>
booleanaddEdgeWithVertices(Graph<V,E> targetGraph, Graph<V,E> sourceGraph, E edge)
Adds the specified edge to the graph, including its vertices if not already included.static <V,E>
EaddEdgeWithVertices(Graph<V,E> g, V sourceVertex, V targetVertex)
Adds the specified source and target vertices to the graph, if not already included, and creates a new edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.static <V,E>
EaddEdgeWithVertices(Graph<V,E> g, V sourceVertex, V targetVertex, double weight)
Adds the specified source and target vertices to the graph, if not already included, and creates a new weighted edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.static <V,E>
booleanaddGraph(Graph<? super V,? super E> destination, Graph<V,E> source)
Adds all the vertices and all the edges of the specified source graph to the specified destination graph.static <V,E>
voidaddGraphReversed(Graph<? super V,? super E> destination, Graph<V,E> source)
Adds all the vertices and all the edges of the specified source digraph to the specified destination digraph, reversing all of the edges.static <V,E>
voidaddIncomingEdges(Graph<V,E> graph, V target, java.lang.Iterable<V> sources)
Add edges from multiple source vertices to one target vertex.static <V,E>
voidaddOutgoingEdges(Graph<V,E> graph, V source, java.lang.Iterable<V> targets)
Add edges from one source vertex to multiple target vertices.static <V,E>
VgetOppositeVertex(Graph<V,E> g, E e, V v)
Gets the vertex opposite another vertex across an edge.static <V,E>
VertexToIntegerMapping<V>getVertexToIntegerMapping(Graph<V,E> graph)
Compute a new mapping from the vertices of a graph to the integer range $[0, n)$ where $n$ is the number of vertices in the graph.static <V,E>
java.util.List<V>neighborListOf(Graph<V,E> g, V vertex)
Returns a list of vertices that are the neighbors of a specified vertex.static <V,E>
java.util.Set<V>neighborSetOf(Graph<V,E> g, V vertex)
Returns a set of vertices that are neighbors of a specified vertex.static <V,E>
java.util.List<V>predecessorListOf(Graph<V,E> g, V vertex)
Returns a list of vertices that are the direct predecessors of a specified vertex.static <V,E>
booleanremoveVertexAndPreserveConnectivity(Graph<V,E> graph, java.lang.Iterable<V> vertices)
Removes all the given vertices from the given graph.static <V,E>
booleanremoveVertexAndPreserveConnectivity(Graph<V,E> graph, V vertex)
Removes the given vertex from the given graph.static <V,E>
booleanremoveVerticesAndPreserveConnectivity(Graph<V,E> graph, java.util.function.Predicate<V> predicate)
Filters vertices from the given graph and subsequently removes them.static <V,E>
java.util.List<V>successorListOf(Graph<V,E> g, V vertex)
Returns a list of vertices that are the direct successors of a specified vertex.static <V,E>
booleantestIncidence(Graph<V,E> g, E e, V v)
Tests whether an edge is incident to a vertex.static <V,E>
Graph<V,E>undirectedGraph(Graph<V,E> g)
Returns an undirected view of the specified graph.static <V,E>
booleanvertexHasPredecessors(Graph<V,E> graph, V vertex)
Check if a vertex has any direct predecessors.static <V,E>
booleanvertexHasSuccessors(Graph<V,E> graph, V vertex)
Check if a vertex has any direct successors.
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Method Detail
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addEdge
public static <V,E> E addEdge(Graph<V,E> g, V sourceVertex, V targetVertex, double weight)
Creates a new edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph for which the edge to be addedsourceVertex
- source vertex of the edgetargetVertex
- target vertex of the edgeweight
- weight of the edge- Returns:
- The newly created edge if added to the graph, otherwise
null
. - Throws:
java.lang.UnsupportedOperationException
- if the graph has no edge supplier- See Also:
Graph.addEdge(Object, Object)
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addEdgeWithVertices
public static <V,E> E addEdgeWithVertices(Graph<V,E> g, V sourceVertex, V targetVertex)
Adds the specified source and target vertices to the graph, if not already included, and creates a new edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph for which the specified edge to be addedsourceVertex
- source vertex of the edgetargetVertex
- target vertex of the edge- Returns:
- The newly created edge if added to the graph, otherwise
null
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addEdgeWithVertices
public static <V,E> boolean addEdgeWithVertices(Graph<V,E> targetGraph, Graph<V,E> sourceGraph, E edge)
Adds the specified edge to the graph, including its vertices if not already included.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
targetGraph
- the graph for which the specified edge to be addedsourceGraph
- the graph in which the specified edge is already presentedge
- edge to add- Returns:
true
if the target graph did not already contain the specified edge.
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addEdgeWithVertices
public static <V,E> E addEdgeWithVertices(Graph<V,E> g, V sourceVertex, V targetVertex, double weight)
Adds the specified source and target vertices to the graph, if not already included, and creates a new weighted edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph for which the specified edge to be addedsourceVertex
- source vertex of the edgetargetVertex
- target vertex of the edgeweight
- weight of the edge- Returns:
- The newly created edge if added to the graph, otherwise
null
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addGraph
public static <V,E> boolean addGraph(Graph<? super V,? super E> destination, Graph<V,E> source)
Adds all the vertices and all the edges of the specified source graph to the specified destination graph. First all vertices of the source graph are added to the destination graph. Then every edge of the source graph is added to the destination graph. This method returnstrue
if the destination graph has been modified as a result of this operation, otherwise it returnsfalse
.The behavior of this operation is undefined if any of the specified graphs is modified while operation is in progress.
- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
destination
- the graph to which vertices and edges are addedsource
- the graph used as source for vertices and edges to add- Returns:
true
if and only if the destination graph has been changed as a result of this operation.
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addGraphReversed
public static <V,E> void addGraphReversed(Graph<? super V,? super E> destination, Graph<V,E> source)
Adds all the vertices and all the edges of the specified source digraph to the specified destination digraph, reversing all of the edges. If you want to do this as a linked view of the source graph (rather than by copying to a destination graph), useEdgeReversedGraph
instead.The behavior of this operation is undefined if any of the specified graphs is modified while operation is in progress.
- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
destination
- the graph to which vertices and edges are addedsource
- the graph used as source for vertices and edges to add- See Also:
EdgeReversedGraph
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addAllEdges
public static <V,E> boolean addAllEdges(Graph<? super V,? super E> destination, Graph<V,E> source, java.util.Collection<? extends E> edges)
Adds a subset of the edges of the specified source graph to the specified destination graph. The behavior of this operation is undefined if either of the graphs is modified while the operation is in progress.addEdgeWithVertices(org.jgrapht.Graph<V, E>, V, V)
is used for the transfer, so source vertexes will be added automatically to the target graph.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
destination
- the graph to which edges are to be addedsource
- the graph used as a source for edges to addedges
- the edges to be added- Returns:
true
if this graph changed as a result of the call
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addAllVertices
public static <V,E> boolean addAllVertices(Graph<? super V,? super E> destination, java.util.Collection<? extends V> vertices)
Adds all of the specified vertices to the destination graph. The behavior of this operation is undefined if the specified vertex collection is modified while the operation is in progress. This method will invoke theGraph.addVertex(Object)
method.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
destination
- the graph to which edges are to be addedvertices
- the vertices to be added to the graph- Returns:
true
if graph changed as a result of the call- Throws:
java.lang.NullPointerException
- if the specified vertices contains one or more null vertices, or if the specified vertex collection isnull
.- See Also:
Graph.addVertex(Object)
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neighborListOf
public static <V,E> java.util.List<V> neighborListOf(Graph<V,E> g, V vertex)
Returns a list of vertices that are the neighbors of a specified vertex. If the graph is a multigraph vertices may appear more than once in the returned list.The method uses
Graph.edgesOf(Object)
to traverse the graph.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph to look for neighbors invertex
- the vertex to get the neighbors of- Returns:
- a list of the vertices that are the neighbors of the specified vertex.
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neighborSetOf
public static <V,E> java.util.Set<V> neighborSetOf(Graph<V,E> g, V vertex)
Returns a set of vertices that are neighbors of a specified vertex.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph to look for neighbors invertex
- the vertex to get the neighbors of- Returns:
- a set of the vertices that are neighbors of the specified vertex
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predecessorListOf
public static <V,E> java.util.List<V> predecessorListOf(Graph<V,E> g, V vertex)
Returns a list of vertices that are the direct predecessors of a specified vertex. If the graph is a multigraph, vertices may appear more than once in the returned list.The method uses
Graph.incomingEdgesOf(Object)
to traverse the graph.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph to look for predecessors invertex
- the vertex to get the predecessors of- Returns:
- a list of the vertices that are the direct predecessors of the specified vertex.
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successorListOf
public static <V,E> java.util.List<V> successorListOf(Graph<V,E> g, V vertex)
Returns a list of vertices that are the direct successors of a specified vertex. If the graph is a multigraph vertices may appear more than once in the returned list.The method uses
Graph.outgoingEdgesOf(Object)
to traverse the graph.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph to look for successors invertex
- the vertex to get the successors of- Returns:
- a list of the vertices that are the direct successors of the specified vertex.
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undirectedGraph
public static <V,E> Graph<V,E> undirectedGraph(Graph<V,E> g)
Returns an undirected view of the specified graph. If the specified graph is directed, returns an undirected view of it. If the specified graph is already undirected, just returns it.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- the graph for which an undirected view is to be returned- Returns:
- an undirected view of the specified graph, if it is directed, or or the specified graph itself if it is already undirected.
- Throws:
java.lang.IllegalArgumentException
- if the graph is neither directed nor undirected- See Also:
AsUndirectedGraph
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testIncidence
public static <V,E> boolean testIncidence(Graph<V,E> g, E e, V v)
Tests whether an edge is incident to a vertex.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- graph containing e and ve
- edge in gv
- vertex in g- Returns:
- true iff e is incident on v
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getOppositeVertex
public static <V,E> V getOppositeVertex(Graph<V,E> g, E e, V v)
Gets the vertex opposite another vertex across an edge.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
g
- graph containing e and ve
- edge in gv
- vertex in g- Returns:
- vertex opposite to v across e
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removeVertexAndPreserveConnectivity
public static <V,E> boolean removeVertexAndPreserveConnectivity(Graph<V,E> graph, V vertex)
Removes the given vertex from the given graph. If the vertex to be removed has one or more predecessors, the predecessors will be connected directly to the successors of the vertex to be removed.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- graph to be mutatedvertex
- vertex to be removed from this graph, if present- Returns:
- true if the graph contained the specified vertex; false otherwise.
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removeVerticesAndPreserveConnectivity
public static <V,E> boolean removeVerticesAndPreserveConnectivity(Graph<V,E> graph, java.util.function.Predicate<V> predicate)
Filters vertices from the given graph and subsequently removes them. If the vertex to be removed has one or more predecessors, the predecessors will be connected directly to the successors of the vertex to be removed.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- graph to be mutatedpredicate
- a non-interfering stateless predicate to apply to each vertex to determine if it should be removed from the graph- Returns:
- true if at least one vertex has been removed; false otherwise.
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removeVertexAndPreserveConnectivity
public static <V,E> boolean removeVertexAndPreserveConnectivity(Graph<V,E> graph, java.lang.Iterable<V> vertices)
Removes all the given vertices from the given graph. If the vertex to be removed has one or more predecessors, the predecessors will be connected directly to the successors of the vertex to be removed.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- to be mutatedvertices
- vertices to be removed from this graph, if present- Returns:
- true if at least one vertex has been removed; false otherwise.
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addOutgoingEdges
public static <V,E> void addOutgoingEdges(Graph<V,E> graph, V source, java.lang.Iterable<V> targets)
Add edges from one source vertex to multiple target vertices. Whether duplicates are created depends on the underlyingGraph
implementation.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- graph to be mutatedsource
- source vertex of the new edgestargets
- target vertices for the new edges
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addIncomingEdges
public static <V,E> void addIncomingEdges(Graph<V,E> graph, V target, java.lang.Iterable<V> sources)
Add edges from multiple source vertices to one target vertex. Whether duplicates are created depends on the underlyingGraph
implementation.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- graph to be mutatedtarget
- target vertex for the new edgessources
- source vertices for the new edges
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vertexHasSuccessors
public static <V,E> boolean vertexHasSuccessors(Graph<V,E> graph, V vertex)
Check if a vertex has any direct successors.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- the graph to look for successorsvertex
- the vertex to look for successors- Returns:
- true if the vertex has any successors, false otherwise
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vertexHasPredecessors
public static <V,E> boolean vertexHasPredecessors(Graph<V,E> graph, V vertex)
Check if a vertex has any direct predecessors.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- the graph to look for predecessorsvertex
- the vertex to look for predecessors- Returns:
- true if the vertex has any predecessors, false otherwise
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getVertexToIntegerMapping
public static <V,E> VertexToIntegerMapping<V> getVertexToIntegerMapping(Graph<V,E> graph)
Compute a new mapping from the vertices of a graph to the integer range $[0, n)$ where $n$ is the number of vertices in the graph.- Type Parameters:
V
- the graph vertex typeE
- the graph edge type- Parameters:
graph
- the input graph- Returns:
- the mapping as an object containing the
vertexMap
and theindexList
- Throws:
java.lang.NullPointerException
- ifgraph
isnull
- See Also:
VertexToIntegerMapping
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