edu.uci.ics.jung.graph.OrderedSparseMultigraph.java Source code

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Here is the source code for edu.uci.ics.jung.graph.OrderedSparseMultigraph.java

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/*
 * Created on Oct 18, 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.LinkedHashMap;
import java.util.LinkedHashSet;
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 <code>Graph</code> that orders its vertex and edge collections
 * according to insertion time, is suitable for sparse graphs, and 
 * permits directed, undirected, and parallel edges.
 */
@SuppressWarnings("serial")
public class OrderedSparseMultigraph<V, E> extends SparseMultigraph<V, E> implements MultiGraph<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 <V, E> Factory<Graph<V, E>> getFactory() {
        return new Factory<Graph<V, E>>() {
            public Graph<V, E> create() {
                return new OrderedSparseMultigraph<V, E>();
            }
        };
    }

    /**
     * Creates a new instance.
     */
    public OrderedSparseMultigraph() {
        vertices = new LinkedHashMap<V, Pair<Set<E>>>();
        edges = new LinkedHashMap<E, Pair<V>>();
        directedEdges = new LinkedHashSet<E>();
    }

    @Override
    public boolean addVertex(V vertex) {
        if (vertex == null) {
            throw new IllegalArgumentException("vertex may not be null");
        }
        if (!containsVertex(vertex)) {
            vertices.put(vertex, new Pair<Set<E>>(new LinkedHashSet<E>(), new LinkedHashSet<E>()));
            return true;
        } else {
            return false;
        }
    }

    @Override
    public Collection<V> getPredecessors(V vertex) {
        if (!containsVertex(vertex))
            return null;

        Set<V> preds = new LinkedHashSet<V>();
        for (E edge : getIncoming_internal(vertex)) {
            if (getEdgeType(edge) == EdgeType.DIRECTED) {
                preds.add(this.getSource(edge));
            } else {
                preds.add(getOpposite(vertex, edge));
            }
        }
        return Collections.unmodifiableCollection(preds);
    }

    @Override
    public Collection<V> getSuccessors(V vertex) {
        if (!containsVertex(vertex))
            return null;

        Set<V> succs = new LinkedHashSet<V>();
        for (E edge : getOutgoing_internal(vertex)) {
            if (getEdgeType(edge) == EdgeType.DIRECTED) {
                succs.add(this.getDest(edge));
            } else {
                succs.add(getOpposite(vertex, edge));
            }
        }
        return Collections.unmodifiableCollection(succs);
    }

    @Override
    public Collection<V> getNeighbors(V vertex) {
        if (!containsVertex(vertex))
            return null;

        Collection<V> out = new LinkedHashSet<V>();
        out.addAll(this.getPredecessors(vertex));
        out.addAll(this.getSuccessors(vertex));
        return out;
    }

    @Override
    public Collection<E> getIncidentEdges(V vertex) {
        if (!containsVertex(vertex))
            return null;

        Collection<E> out = new LinkedHashSet<E>();
        out.addAll(this.getInEdges(vertex));
        out.addAll(this.getOutEdges(vertex));
        return out;
    }
}