edu.uci.ics.jung.visualization.layout.CachingLayout.java Source code

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Here is the source code for edu.uci.ics.jung.visualization.layout.CachingLayout.java

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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 Aug 23, 2005
 */

package edu.uci.ics.jung.visualization.layout;

import java.awt.geom.Point2D;

import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;

import edu.uci.ics.jung.algorithms.layout.Layout;
import edu.uci.ics.jung.algorithms.layout.LayoutDecorator;
import edu.uci.ics.jung.graph.Graph;
import edu.uci.ics.jung.visualization.util.Caching;

/**
 * A LayoutDecorator that caches locations in a clearable Map. This can be used to ensure that
 * edge endpoints are always the same as vertex locations when they are drawn in the render loop 
 * during the time that the layout's relaxer thread is changing the locations.
 * 
 * @see LayoutDecorator
 * @author Tom Nelson 
 *
 */
public class CachingLayout<V, E> extends LayoutDecorator<V, E> implements Caching {

    protected LoadingCache<V, Point2D> locations;

    public CachingLayout(Layout<V, E> delegate) {
        super(delegate);
        Function<V, Point2D> chain = Functions.<V, Point2D, Point2D>compose(new Function<Point2D, Point2D>() {
            public Point2D apply(Point2D p) {
                return (Point2D) p.clone();
            }
        }, delegate);
        this.locations = CacheBuilder.newBuilder().build(CacheLoader.from(chain));
    }

    @Override
    public void setGraph(Graph<V, E> graph) {
        delegate.setGraph(graph);
    }

    public void clear() {
        this.locations = CacheBuilder.newBuilder().build(new CacheLoader<V, Point2D>() {
            public Point2D load(V vertex) {
                return new Point2D.Double();
            }
        });
    }

    public void init() {
    }

    public Point2D apply(V v) {
        return locations.getUnchecked(v);
    }
}