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Graph implementations for the JUNG project
/*
* Created on Mar 26, 2007
*
* Copyright (c) 2007, The JUNG Authors
*
* All rights reserved.
*
* This software is open-source under the BSD license; see either
* "license.txt" or
* https://github.com/jrtom/jung/blob/master/LICENSE for a description.
*/
package edu.uci.ics.jung.graph;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import com.google.common.base.Supplier;
import edu.uci.ics.jung.graph.util.EdgeType;
import edu.uci.ics.jung.graph.util.Pair;
/**
* An implementation of DirectedGraph suitable for sparse graphs.
*/
@SuppressWarnings("serial")
public class DirectedSparseGraph extends AbstractTypedGraph implements
DirectedGraph
{
/**
* @param the vertex type for the graph Supplier
* @param the edge type for the graph Supplier
* @return a {@code Supplier} that creates an instance of this graph type.
*/
public static final Supplier> getFactory() {
return new Supplier> () {
public DirectedGraph get() {
return new DirectedSparseGraph();
}
};
}
protected Map>> vertices; // Map of vertices to Pair of adjacency maps {incoming, outgoing}
// of neighboring vertices to incident edges
protected Map> edges; // Map of edges to incident vertex pairs
/**
* Creates an instance.
*/
public DirectedSparseGraph()
{
super(EdgeType.DIRECTED);
vertices = new HashMap>>();
edges = new HashMap>();
}
@Override
public boolean addEdge(E edge, Pair endpoints, EdgeType edgeType)
{
this.validateEdgeType(edgeType);
Pair new_endpoints = getValidatedEndpoints(edge, endpoints);
if (new_endpoints == null)
return false;
V source = new_endpoints.getFirst();
V dest = new_endpoints.getSecond();
if (findEdge(source, dest) != null)
return false;
edges.put(edge, new_endpoints);
if (!vertices.containsKey(source))
this.addVertex(source);
if (!vertices.containsKey(dest))
this.addVertex(dest);
// map source of this edge to and vice versa
vertices.get(source).getSecond().put(dest, edge);
vertices.get(dest).getFirst().put(source, edge);
return true;
}
@Override
public E findEdge(V v1, V v2)
{
if (!containsVertex(v1) || !containsVertex(v2))
return null;
return vertices.get(v1).getSecond().get(v2);
}
@Override
public Collection findEdgeSet(V v1, V v2)
{
if (!containsVertex(v1) || !containsVertex(v2))
return null;
ArrayList edge_collection = new ArrayList(1);
E e = findEdge(v1, v2);
if (e == null)
return edge_collection;
edge_collection.add(e);
return edge_collection;
}
protected Collection getIncoming_internal(V vertex)
{
return vertices.get(vertex).getFirst().values();
}
protected Collection getOutgoing_internal(V vertex)
{
return vertices.get(vertex).getSecond().values();
}
protected Collection getPreds_internal(V vertex)
{
return vertices.get(vertex).getFirst().keySet();
}
protected Collection getSuccs_internal(V vertex)
{
return vertices.get(vertex).getSecond().keySet();
}
public Collection getInEdges(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getIncoming_internal(vertex));
}
public Collection getOutEdges(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getOutgoing_internal(vertex));
}
public Collection getPredecessors(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getPreds_internal(vertex));
}
public Collection getSuccessors(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getSuccs_internal(vertex));
}
public Pair getEndpoints(E edge)
{
if (!containsEdge(edge))
return null;
return edges.get(edge);
}
public V getSource(E directed_edge)
{
if (!containsEdge(directed_edge))
return null;
return edges.get(directed_edge).getFirst();
}
public V getDest(E directed_edge)
{
if (!containsEdge(directed_edge))
return null;
return edges.get(directed_edge).getSecond();
}
public boolean isSource(V vertex, E edge)
{
if (!containsEdge(edge) || !containsVertex(vertex))
return false;
return vertex.equals(this.getEndpoints(edge).getFirst());
}
public boolean isDest(V vertex, E edge)
{
if (!containsEdge(edge) || !containsVertex(vertex))
return false;
return vertex.equals(this.getEndpoints(edge).getSecond());
}
public Collection getEdges()
{
return Collections.unmodifiableCollection(edges.keySet());
}
public Collection getVertices()
{
return Collections.unmodifiableCollection(vertices.keySet());
}
public boolean containsVertex(V vertex)
{
return vertices.containsKey(vertex);
}
public boolean containsEdge(E edge)
{
return edges.containsKey(edge);
}
public int getEdgeCount()
{
return edges.size();
}
public int getVertexCount()
{
return vertices.size();
}
public Collection getNeighbors(V vertex)
{
if (!containsVertex(vertex))
return null;
Collection neighbors = new HashSet();
neighbors.addAll(getPreds_internal(vertex));
neighbors.addAll(getSuccs_internal(vertex));
return Collections.unmodifiableCollection(neighbors);
}
public Collection getIncidentEdges(V vertex)
{
if (!containsVertex(vertex))
return null;
Collection incident_edges = new HashSet();
incident_edges.addAll(getIncoming_internal(vertex));
incident_edges.addAll(getOutgoing_internal(vertex));
return Collections.unmodifiableCollection(incident_edges);
}
public boolean addVertex(V vertex)
{
if(vertex == null) {
throw new IllegalArgumentException("vertex may not be null");
}
if (!containsVertex(vertex)) {
vertices.put(vertex, new Pair>(new HashMap(), new HashMap()));
return true;
} else {
return false;
}
}
public boolean removeVertex(V vertex) {
if (!containsVertex(vertex))
return false;
// copy to avoid concurrent modification in removeEdge
ArrayList incident = new ArrayList(getIncoming_internal(vertex));
incident.addAll(getOutgoing_internal(vertex));
for (E edge : incident)
removeEdge(edge);
vertices.remove(vertex);
return true;
}
public boolean removeEdge(E edge) {
if (!containsEdge(edge))
return false;
Pair endpoints = this.getEndpoints(edge);
V source = endpoints.getFirst();
V dest = endpoints.getSecond();
// remove vertices from each others' adjacency maps
vertices.get(source).getSecond().remove(dest);
vertices.get(dest).getFirst().remove(source);
edges.remove(edge);
return true;
}
}