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Graph implementations for the JUNG project
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/*
* Created on Apr 2, 2006
*
* Copyright (c) 2006, 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.io.Serializable;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import edu.uci.ics.jung.graph.util.EdgeType;
import edu.uci.ics.jung.graph.util.Pair;
/**
* Abstract implementation of the Graph
interface.
* Designed to simplify implementation of new graph classes.
*
* @author Joshua O'Madadhain
*/
@SuppressWarnings("serial")
public abstract class AbstractGraph implements Graph, Serializable
{
public boolean addEdge(E edge, Collection extends V> vertices)
{
return addEdge(edge, vertices, this.getDefaultEdgeType());
}
@SuppressWarnings("unchecked")
public boolean addEdge(E edge, Collection extends V> vertices, EdgeType edgeType) {
if (vertices == null)
throw new IllegalArgumentException("'vertices' parameter must not be null");
if (vertices.size() == 2)
return addEdge(edge,
vertices instanceof Pair ? (Pair)vertices : new Pair(vertices),
edgeType);
else if (vertices.size() == 1)
{
V vertex = vertices.iterator().next();
return addEdge(edge, new Pair(vertex, vertex), edgeType);
}
else
throw new IllegalArgumentException("Graph objects connect 1 or 2 vertices; vertices arg has " + vertices.size());
}
public boolean addEdge(E e, V v1, V v2)
{
return addEdge(e, v1, v2, this.getDefaultEdgeType());
}
public boolean addEdge(E e, V v1, V v2, EdgeType edge_type)
{
return addEdge(e, new Pair(v1, v2), edge_type);
}
/**
* Adds {@code edge} to this graph with the specified {@code endpoints},
* with the default edge type.
*
* @param edge the edge to be added
* @param endpoints the endpoints to be connected to this edge
* @return {@code true} iff the graph was modified as a result of this call
*/
public boolean addEdge(E edge, Pair extends V> endpoints)
{
return addEdge(edge, endpoints, this.getDefaultEdgeType());
}
/**
* Adds {@code edge} to this graph with the specified {@code endpoints}
* and {@code EdgeType}.
*
* @param edge the edge to be added
* @param endpoints the endpoints to be connected to this edge
* @param edgeType the type of edge to add
* @return {@code} true iff the graph was modified as a result of this call
*/
public abstract boolean addEdge(E edge, Pair extends V> endpoints, EdgeType edgeType);
protected Pair getValidatedEndpoints(E edge, Pair extends V> endpoints)
{
if (edge == null)
throw new IllegalArgumentException("input edge may not be null");
if (endpoints == null)
throw new IllegalArgumentException("endpoints may not be null");
Pair new_endpoints = new Pair(endpoints.getFirst(), endpoints.getSecond());
if (containsEdge(edge))
{
Pair existing_endpoints = getEndpoints(edge);
if (!existing_endpoints.equals(new_endpoints)) {
throw new IllegalArgumentException("edge " + edge +
" already exists in this graph with endpoints " + existing_endpoints +
" and cannot be added with endpoints " + endpoints);
} else {
return null;
}
}
return new_endpoints;
}
public int inDegree(V vertex)
{
return this.getInEdges(vertex).size();
}
public int outDegree(V vertex)
{
return this.getOutEdges(vertex).size();
}
public boolean isPredecessor(V v1, V v2)
{
return this.getPredecessors(v1).contains(v2);
}
public boolean isSuccessor(V v1, V v2)
{
return this.getSuccessors(v1).contains(v2);
}
public int getPredecessorCount(V vertex)
{
return this.getPredecessors(vertex).size();
}
public int getSuccessorCount(V vertex)
{
return this.getSuccessors(vertex).size();
}
public boolean isNeighbor(V v1, V v2)
{
if (!containsVertex(v1) || !containsVertex(v2))
throw new IllegalArgumentException("At least one of these not in this graph: " + v1 + ", " + v2);
return this.getNeighbors(v1).contains(v2);
}
public boolean isIncident(V vertex, E edge)
{
if (!containsVertex(vertex) || !containsEdge(edge))
throw new IllegalArgumentException("At least one of these not in this graph: " + vertex + ", " + edge);
return this.getIncidentEdges(vertex).contains(edge);
}
public int getNeighborCount(V vertex)
{
if (!containsVertex(vertex))
throw new IllegalArgumentException(vertex + " is not a vertex in this graph");
return this.getNeighbors(vertex).size();
}
public int degree(V vertex)
{
if (!containsVertex(vertex))
throw new IllegalArgumentException(vertex + " is not a vertex in this graph");
return this.getIncidentEdges(vertex).size();
}
public int getIncidentCount(E edge)
{
Pair incident = this.getEndpoints(edge);
if (incident == null)
return 0;
if (incident.getFirst() == incident.getSecond())
return 1;
else
return 2;
}
public V getOpposite(V vertex, E edge)
{
Pair incident = this.getEndpoints(edge);
V first = incident.getFirst();
V second = incident.getSecond();
if (vertex.equals(first))
return second;
else if (vertex.equals(second))
return first;
else
throw new IllegalArgumentException(vertex + " is not incident to " + edge + " in this graph");
}
public E findEdge(V v1, V v2)
{
for (E e : getOutEdges(v1))
{
if (getOpposite(v1, e).equals(v2))
return e;
}
return null;
}
public Collection findEdgeSet(V v1, V v2)
{
if (!getVertices().contains(v1))
throw new IllegalArgumentException(v1 + " is not an element of this graph");
if (!getVertices().contains(v2))
throw new IllegalArgumentException(v2 + " is not an element of this graph");
Collection edges = new ArrayList();
for (E e : getOutEdges(v1))
{
if (getOpposite(v1, e).equals(v2))
edges.add(e);
}
return Collections.unmodifiableCollection(edges);
}
public Collection getIncidentVertices(E edge)
{
Pair endpoints = this.getEndpoints(edge);
Collection incident = new ArrayList();
incident.add(endpoints.getFirst());
incident.add(endpoints.getSecond());
return Collections.unmodifiableCollection(incident);
}
@Override
public String toString() {
StringBuffer sb = new StringBuffer("Vertices:");
for(V v : getVertices()) {
sb.append(v+",");
}
sb.setLength(sb.length()-1);
sb.append("\nEdges:");
for(E e : getEdges()) {
Pair ep = getEndpoints(e);
sb.append(e+"["+ep.getFirst()+","+ep.getSecond()+"] ");
}
return sb.toString();
}
}
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