/*
 * 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.
 * 
 *
 * Created on Mar 28, 2005
 */
package edu.uci.ics.jung.visualization.picking;

import java.awt.event.ItemEvent;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

/**
 * Maintains the state of what has been 'picked' in the graph.
 * The <code>Sets</code> are constructed so that their iterators
 * will traverse them in the order in which they are picked.
 * 
 * @author Tom Nelson 
 * @author Joshua O'Madadhain
 * 
 */
public class MultiPickedState<T> extends AbstractPickedState<T> implements PickedState<T> {
    /**
     * the 'picked' vertices
     */
    protected Set<T> picked = new LinkedHashSet<T>();
    
    /**
     * @see PickedState#pick(ArchetypeVertex, boolean)
     */
    public boolean pick(T v, boolean state) {
        boolean prior_state = this.picked.contains(v);
        if (state) {
            picked.add(v);
            if(prior_state == false) {
                fireItemStateChanged(new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
                        v, ItemEvent.SELECTED));
            }

        } else {
            picked.remove(v);
            if(prior_state == true) {
                fireItemStateChanged(new ItemEvent(this, ItemEvent.ITEM_STATE_CHANGED,
                    v, ItemEvent.DESELECTED));
            }

        }
        return prior_state;
    }

    /**
     * @see edu.uci.ics.jung.visualization.picking.PickedState#clearPickedVertices()
     */
    public void clear() {
        Collection<T> unpicks = new ArrayList<T>(picked);
        for(T v : unpicks) {
            pick(v, false);
        }
        picked.clear();

    }

    /**
     * @see edu.uci.ics.jung.visualization.picking.PickedState#getPickedEdges()
     */
    public Set<T> getPicked() {
        return Collections.unmodifiableSet(picked);
    }
    
    /**
     * @see edu.uci.ics.jung.visualization.picking.PickedState#isPicked(ArchetypeEdge)
     */
    public boolean isPicked(T e) {
        return picked.contains(e);
    }

    /**
     * for the ItemSelectable interface contract
     */
    @SuppressWarnings("unchecked")
    public T[] getSelectedObjects() {
        List<T> list = new ArrayList<T>(picked);
        return (T[])list.toArray();
    }
    
}