Package org._3pq.jgrapht
Class GraphHelper
- java.lang.Object
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- org._3pq.jgrapht.GraphHelper
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public final class GraphHelper extends java.lang.Object
A collection of utilities to assist the working with graphs.- Since:
- Jul 31, 2003
- Author:
- Barak Naveh
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static Edge
addEdge(Graph g, java.lang.Object sourceVertex, java.lang.Object targetVertex, double weight)
Creates a new edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.static Edge
addEdgeWithVertices(Graph g, java.lang.Object sourceVertex, java.lang.Object 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 Edge
addEdgeWithVertices(Graph g, java.lang.Object sourceVertex, java.lang.Object 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 boolean
addEdgeWithVertices(Graph g, Edge e)
Adds the specified edge to the specified graph including its vertices.static boolean
addGraph(Graph destination, Graph source)
Adds all the vertices and all the edges of the specified source graph to the specified destination graph.static void
addGraphReversed(DirectedGraph destination, DirectedGraph 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 java.util.List
neighborListOf(Graph g, java.lang.Object vertex)
Returns a list of vertices that are the neighbors of a specified vertex.static java.util.List
predecessorListOf(DirectedGraph g, java.lang.Object vertex)
Returns a list of vertices that are the predecessors of a specified vertex.static java.util.List
successorListOf(DirectedGraph g, java.lang.Object vertex)
Returns a list of vertices that are the successors of a specified vertex.static UndirectedGraph
undirectedGraph(Graph g)
Returns an undirected view of the specified graph.
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Method Detail
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addEdge
public static Edge addEdge(Graph g, java.lang.Object sourceVertex, java.lang.Object targetVertex, double weight)
Creates a new edge and adds it to the specified graph similarly to theGraph.addEdge(Object, Object)
method.- Parameters:
g
- the graph for which the edge to be added.sourceVertex
- source vertex of the edge.targetVertex
- target vertex of the edge.weight
- weight of the edge.- Returns:
- The newly created edge if added to the graph, otherwise
null
. - See Also:
Graph.addEdge(Object, Object)
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addEdgeWithVertices
public static boolean addEdgeWithVertices(Graph g, Edge e)
Adds the specified edge to the specified graph including its vertices. If any of the vertices of the specified edge are not already in the graph they are also added (before the edge is added).- Parameters:
g
- the graph for which the specified edge to be added.e
- the edge to be added to the graph (including its vertices).- Returns:
true
if and only if the specified edge was not already contained in the graph.
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addEdgeWithVertices
public static Edge addEdgeWithVertices(Graph g, java.lang.Object sourceVertex, java.lang.Object 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.- Parameters:
g
- the graph for which the specified edge to be added.sourceVertex
- source vertex of the edge.targetVertex
- target vertex of the edge.- Returns:
- The newly created edge if added to the graph, otherwise
null
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addEdgeWithVertices
public static Edge addEdgeWithVertices(Graph g, java.lang.Object sourceVertex, java.lang.Object 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.- Parameters:
g
- the graph for which the specified edge to be added.sourceVertex
- source vertex of the edge.targetVertex
- target vertex of the edge.weight
- weight of the edge.- Returns:
- The newly created edge if added to the graph, otherwise
null
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addGraph
public static boolean addGraph(Graph destination, Graph 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.
- Parameters:
destination
- the graph to which vertices and edges are added.source
- 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 void addGraphReversed(DirectedGraph destination, DirectedGraph source)
Adds all the vertices and all the edges of the specified source digraph to the specified destination digraph, reversing all of the edges.The behavior of this operation is undefined if any of the specified graphs is modified while operation is in progress.
- Parameters:
destination
- the graph to which vertices and edges are added.source
- the graph used as source for vertices and edges to add.
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neighborListOf
public static java.util.List neighborListOf(Graph g, java.lang.Object 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.- Parameters:
g
- the graph to look for neighbors in.vertex
- 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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predecessorListOf
public static java.util.List predecessorListOf(DirectedGraph g, java.lang.Object vertex)
Returns a list of vertices that are the predecessors of a specified vertex. If the graph is a multigraph, vertices may appear more than once in the returned list.- Parameters:
g
- the graph to look for predecessors in.vertex
- the vertex to get the predecessors of.- Returns:
- a list of the vertices that are the predecessors of the specified vertex.
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successorListOf
public static java.util.List successorListOf(DirectedGraph g, java.lang.Object vertex)
Returns a list of vertices that are the successors of a specified vertex. If the graph is a multigraph vertices may appear more than once in the returned list.- Parameters:
g
- the graph to look for successors in.vertex
- the vertex to get the successors of.- Returns:
- a list of the vertices that are the successors of the specified vertex.
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undirectedGraph
public static UndirectedGraph undirectedGraph(Graph 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 undirected, just returns it.- Parameters:
g
- the graph for which an undirected view to be returned.- Returns:
- an undirected view of the specified graph, if it is directed, or or the specified graph itself if it is undirected.
- Throws:
java.lang.IllegalArgumentException
- if the graph is neither DirectedGraph nor UndirectedGraph.- See Also:
AsUndirectedGraph
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