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Core visualization support for the JUNG project
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/*
 * Copyright (c) 2005, 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.
 * 
 * Created on Oct 8, 2004
 *
 */
package edu.uci.ics.jung.visualization.layout;

import java.awt.Dimension;
import java.awt.geom.Point2D;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Maps;

import edu.uci.ics.jung.algorithms.layout.Layout;
import edu.uci.ics.jung.visualization.util.Caching;
import edu.uci.ics.jung.visualization.util.ChangeEventSupport;


/**
 * Implementation of PersistentLayout.
 * Defers to another layout until 'restore' is called,
 * then it uses the saved vertex locations
 * 
 * @author Tom Nelson
 * 
 *  
 */
public class PersistentLayoutImpl extends ObservableCachingLayout
    implements PersistentLayout,  ChangeEventSupport, Caching {

    /**
     * a container for Vertices
     */
    protected Map locations;
    
    /**
     * a collection of Vertices that should not move
     */
    protected Set dontmove;

    /**
     * whether the graph is locked (stops the VisualizationViewer rendering thread)
     */
    protected boolean locked;

    /**
     * create an instance with a passed layout
     * create containers for graph components
     * @param layout the layout whose positions are to be persisted
     */
    public PersistentLayoutImpl(Layout layout) {
        super(layout);
	this.locations = Maps.asMap(
	    ImmutableSet.copyOf(layout.getGraph().getVertices()),
	    new RandomPointFactory(getSize()));
        this.dontmove = new HashSet();
    }

    /**
     * This method calls initialize_local_vertex for each vertex, and
     * also adds initial coordinate information for each vertex. (The vertex's
     * initial location is set by calling initializeLocation.
     */
    protected void initializeLocations() {
        for(V v : getGraph().getVertices()) {
            Point2D coord = delegate.apply(v);
            if (!dontmove.contains(v))
                initializeLocation(v, coord);
        }
    }


    /**
     * Sets persisted location for a vertex within the dimensions of the space.
     * If the vertex has not been persisted, sets a random location. If you want
     * to initialize in some different way, override this method.
     * 
     * @param v the vertex whose location is to be initialized
     * @param coord the location 
     */
    protected void initializeLocation(V v, Point2D coord) {
        Point point = locations.get(v);
        coord.setLocation(point.x, point.y);
    }

    /**
     * save the Vertex locations to a file
     * @param fileName the file to save to	
     * @throws IOException if the file cannot be used
     */
    public void persist(String fileName) throws IOException {

        for(V v : getGraph().getVertices()) {
            Point p = new Point(transform(v));
            locations.put(v, p);
        }
        ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(
                fileName));
        oos.writeObject(locations);
        oos.close();
    }

    /**
     * Restore the graph Vertex locations from a file
     * @param fileName the file to use
     * @throws IOException for file problems
     * @throws ClassNotFoundException for classpath problems
     */
    @SuppressWarnings("unchecked")
	public void restore(String fileName) throws IOException,
            ClassNotFoundException {
        ObjectInputStream ois = new ObjectInputStream(new FileInputStream(
                fileName));
        locations = (Map) ois.readObject();
        ois.close();
        initializeLocations();
        locked = true;
        fireStateChanged();
    }

    public void lock(boolean locked) {
        this.locked = locked;
    }

    /*
     * (non-Javadoc)
     * 
     * @see edu.uci.ics.jung.visualization.Layout#incrementsAreDone()
     */
    public boolean done() {
        return super.done() || locked;
    }

    /*
     * (non-Javadoc)
     * 
     * @see edu.uci.ics.jung.visualization.Layout#lockVertex(edu.uci.ics.jung.graph.Vertex)
     */
    public void lock(V v, boolean state) {
        dontmove.add(v);
        delegate.lock(v, state);
    }
    
    @SuppressWarnings("serial")
	public static class RandomPointFactory implements Function, Serializable {

    	Dimension d;
    	public RandomPointFactory(Dimension d) {
    		this.d = d;
    	}
		public edu.uci.ics.jung.visualization.layout.PersistentLayout.Point apply(V v) {
	            double x = Math.random() * d.width;
	            double y = Math.random() * d.height;
				return new Point(x,y);
		}
    }

}