/*
* Created on Mar 26, 2007
*
* Copyright (c) 2007, 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.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
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 <code>DirectedGraph</code> suitable for sparse graphs.
*/
@SuppressWarnings("serial")
public class DirectedSparseGraph<V,E> extends AbstractTypedGraph<V, E> implements
DirectedGraph<V, E>
{
/**
* Returns a {@code Factory} that creates an instance of this graph type.
* @param <V> the vertex type for the graph factory
* @param <E> the edge type for the graph factory
*/
public static final <V,E> Factory<DirectedGraph<V,E>> getFactory() {
return new Factory<DirectedGraph<V,E>> () {
public DirectedGraph<V,E> create() {
return new DirectedSparseGraph<V,E>();
}
};
}
protected Map<V, Pair<Map<V,E>>> vertices; // Map of vertices to Pair of adjacency maps {incoming, outgoing}
// of neighboring vertices to incident edges
protected Map<E, Pair<V>> edges; // Map of edges to incident vertex pairs
/**
* Creates an instance.
*/
public DirectedSparseGraph()
{
super(EdgeType.DIRECTED);
vertices = new HashMap<V, Pair<Map<V,E>>>();
edges = new HashMap<E, Pair<V>>();
}
@Override
public boolean addEdge(E edge, Pair<? extends V> endpoints, EdgeType edgeType)
{
this.validateEdgeType(edgeType);
Pair<V> 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 <dest, edge> 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<E> findEdgeSet(V v1, V v2)
{
if (!containsVertex(v1) || !containsVertex(v2))
return null;
ArrayList<E> edge_collection = new ArrayList<E>(1);
E e = findEdge(v1, v2);
if (e == null)
return edge_collection;
edge_collection.add(e);
return edge_collection;
}
protected Collection<E> getIncoming_internal(V vertex)
{
return vertices.get(vertex).getFirst().values();
}
protected Collection<E> getOutgoing_internal(V vertex)
{
return vertices.get(vertex).getSecond().values();
}
protected Collection<V> getPreds_internal(V vertex)
{
return vertices.get(vertex).getFirst().keySet();
}
protected Collection<V> getSuccs_internal(V vertex)
{
return vertices.get(vertex).getSecond().keySet();
}
public Collection<E> getInEdges(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getIncoming_internal(vertex));
}
public Collection<E> getOutEdges(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getOutgoing_internal(vertex));
}
public Collection<V> getPredecessors(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getPreds_internal(vertex));
}
public Collection<V> getSuccessors(V vertex)
{
if (!containsVertex(vertex))
return null;
return Collections.unmodifiableCollection(getSuccs_internal(vertex));
}
public Pair<V> 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<E> getEdges()
{
return Collections.unmodifiableCollection(edges.keySet());
}
public Collection<V> 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<V> getNeighbors(V vertex)
{
if (!containsVertex(vertex))
return null;
Collection<V> neighbors = new HashSet<V>();
neighbors.addAll(getPreds_internal(vertex));
neighbors.addAll(getSuccs_internal(vertex));
return Collections.unmodifiableCollection(neighbors);
}
public Collection<E> getIncidentEdges(V vertex)
{
if (!containsVertex(vertex))
return null;
Collection<E> incident_edges = new HashSet<E>();
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<Map<V,E>>(new HashMap<V,E>(), new HashMap<V,E>()));
return true;
} else {
return false;
}
}
public boolean removeVertex(V vertex) {
if (!containsVertex(vertex))
return false;
// copy to avoid concurrent modification in removeEdge
ArrayList<E> incident = new ArrayList<E>(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<V> 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;
}
}