edu.uci.ics.jung.graph.DirectedSparseMultigraph Maven / Gradle / Ivy
/*
* Created on Oct 17, 2005
*
* Copyright (c) 2005, the JUNG Project and the Regents of the University
* of California
* All rights reserved.
*
* This software is open-source under the BSD license; see either
* "license.txt" or
* http://jung.sourceforge.net/license.txt for a description.
*/
package edu.uci.ics.jung.graph;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import org.apache.commons.collections15.Factory;
import edu.uci.ics.jung.graph.util.EdgeType;
import edu.uci.ics.jung.graph.util.Pair;
/**
* An implementation of DirectedGraph, suitable for sparse graphs,
* that permits parallel edges.
*/
@SuppressWarnings("serial")
public class DirectedSparseMultigraph
extends AbstractTypedGraph
implements DirectedGraph, MultiGraph {
/**
* Returns a {@code Factory} that creates an instance of this graph type.
* @param the vertex type for the graph factory
* @param the edge type for the graph factory
*/
public static Factory> getFactory() {
return new Factory> () {
public DirectedGraph create() {
return new DirectedSparseMultigraph();
}
};
}
protected Map>> vertices; // Map of vertices to Pair of adjacency sets {incoming, outgoing}
protected Map> edges; // Map of edges to incident vertex pairs
/**
* Creates a new instance.
*/
public DirectedSparseMultigraph() {
super(EdgeType.DIRECTED);
vertices = new HashMap>>();
edges = new HashMap>();
}
public Collection getEdges() {
return Collections.unmodifiableCollection(edges.keySet());
}
public Collection getVertices() {
return Collections.unmodifiableCollection(vertices.keySet());
}
public boolean containsVertex(V vertex) {
return vertices.keySet().contains(vertex);
}
public boolean containsEdge(E edge) {
return edges.keySet().contains(edge);
}
protected Collection getIncoming_internal(V vertex)
{
return vertices.get(vertex).getFirst();
}
protected Collection getOutgoing_internal(V vertex)
{
return vertices.get(vertex).getSecond();
}
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 HashSet(), new HashSet()));
return true;
} else {
return false;
}
}
public boolean removeVertex(V vertex) {
if (!containsVertex(vertex))
return false;
// copy to avoid concurrent modification in removeEdge
Set incident = new HashSet(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 edge from incident vertices' adjacency sets
getOutgoing_internal(source).remove(edge);
getIncoming_internal(dest).remove(edge);
edges.remove(edge);
return true;
}
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;
Set preds = new HashSet();
for (E edge : getIncoming_internal(vertex))
preds.add(this.getSource(edge));
return Collections.unmodifiableCollection(preds);
}
public Collection getSuccessors(V vertex) {
if (!containsVertex(vertex))
return null;
Set succs = new HashSet();
for (E edge : getOutgoing_internal(vertex))
succs.add(this.getDest(edge));
return Collections.unmodifiableCollection(succs);
}
public Collection getNeighbors(V vertex) {
if (!containsVertex(vertex))
return null;
Collection neighbors = new HashSet();
for (E edge : getIncoming_internal(vertex))
neighbors.add(this.getSource(edge));
for (E edge : getOutgoing_internal(vertex))
neighbors.add(this.getDest(edge));
return Collections.unmodifiableCollection(neighbors);
}
public Collection getIncidentEdges(V vertex) {
if (!containsVertex(vertex))
return null;
Collection incident = new HashSet();
incident.addAll(getIncoming_internal(vertex));
incident.addAll(getOutgoing_internal(vertex));
return incident;
}
@Override
public E findEdge(V v1, V v2) {
if (!containsVertex(v1) || !containsVertex(v2))
return null;
for (E edge : getOutgoing_internal(v1))
if (this.getDest(edge).equals(v2))
return edge;
return null;
}
@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;
edges.put(edge, new_endpoints);
V source = new_endpoints.getFirst();
V dest = new_endpoints.getSecond();
if (!containsVertex(source))
this.addVertex(source);
if (!containsVertex(dest))
this.addVertex(dest);
getIncoming_internal(dest).add(edge);
getOutgoing_internal(source).add(edge);
return true;
}
public V getSource(E edge) {
if (!containsEdge(edge))
return null;
return this.getEndpoints(edge).getFirst();
}
public V getDest(E edge) {
if (!containsEdge(edge))
return null;
return this.getEndpoints(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 Pair getEndpoints(E edge) {
return edges.get(edge);
}
public int getEdgeCount() {
return edges.size();
}
public int getVertexCount() {
return vertices.size();
}
}