com.phoenixst.plexus.DefaultOrientedForestView.java Source code

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Here is the source code for com.phoenixst.plexus.DefaultOrientedForestView.java

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/*
 *  $Id: DefaultOrientedForestView.java,v 1.16 2006/06/07 21:08:23 rconner Exp $
 *
 *  Copyright (C) 1994-2006 by Phoenix Software Technologists,
 *  Inc. and others.  All rights reserved.
 *
 *  THIS PROGRAM AND DOCUMENTATION IS PROVIDED UNDER THE TERMS OF THE
 *  COMMON PUBLIC LICENSE ("AGREEMENT") WHICH ACCOMPANIES IT.  ANY
 *  USE, REPRODUCTION OR DISTRIBUTION OF THE PROGRAM CONSTITUTES
 *  RECIPIENT'S ACCEPTANCE OF THE AGREEMENT.
 *
 *  The license text can also be found at
 *    http://opensource.org/licenses/cpl.php
 */

package com.phoenixst.plexus;

import java.io.*;
import java.util.Collection;

import org.apache.commons.collections.Predicate;

/**
 *  A default view implementation of the <code>OrientedForest</code>
 *  interface.
 *
 *  @version    $Revision: 1.16 $
 *  @author     Ray A. Conner
 *
 *  @since      1.0
 */
public class DefaultOrientedForestView extends AbstractOrientedForest implements GraphView, Serializable {

    private static final long serialVersionUID = 1L;

    /**
     *  The Graph of which this is a view.
     *
     *  @serial
     */
    private final Graph graph;

    /**
     *  The parent Predicate.
     *
     *  @serial
     */
    private final Predicate parentPredicate;

    /**
     *  The child Predicate.
     *
     *  @serial
     */
    private final Predicate childPredicate;

    ////////////////////////////////////////
    // Constructor
    ////////////////////////////////////////

    /**
     *  Creates a new <code>DefaultOrientedForestView</code>.
     */
    public DefaultOrientedForestView(Graph graph, Predicate parentPredicate, Predicate childPredicate) {
        super();
        this.graph = graph;
        this.parentPredicate = parentPredicate;
        this.childPredicate = childPredicate;
        if (graph == null) {
            throw new IllegalArgumentException("Delegate Graph is null.");
        }
    }

    ////////////////////////////////////////
    // Serialization methods
    ////////////////////////////////////////

    private void readObject(ObjectInputStream in) throws ClassNotFoundException, IOException {
        in.defaultReadObject();
        if (graph == null) {
            throw new InvalidObjectException("Graph is null.");
        }
    }

    ////////////////////////////////////////
    // GraphView
    ////////////////////////////////////////

    public Graph getGraph() {
        return graph;
    }

    ////////////////////////////////////////
    // OrientedForest
    ////////////////////////////////////////

    public Object getParent(Object node) {
        return graph.getAdjacentNode(node, parentPredicate);
    }

    public Graph.Edge getParentEdge(Object node) {
        return graph.getIncidentEdge(node, parentPredicate);
    }

    public Traverser childTraverser(Object node) {
        return graph.traverser(node, childPredicate);
    }

    public Collection rootNodes() {
        return graph.nodes(new RootPredicate(graph, parentPredicate));
    }

    public boolean isLeaf(Object node) {
        return graph.getIncidentEdge(node, childPredicate) == null;
    }

    ////////////////////////////////////////
    // Private classes
    ////////////////////////////////////////

    private static class RootPredicate implements Predicate {
        private final Graph graph;
        private final Predicate parentPredicate;

        RootPredicate(Graph graph, Predicate parentPredicate) {
            super();
            this.graph = graph;
            this.parentPredicate = parentPredicate;
        }

        public boolean evaluate(Object object) {
            return graph.getIncidentEdge(object, parentPredicate) == null;
        }
    }

}