/*
 * The Unified Mapping Platform (JUMP) is an extensible, interactive GUI
 * for visualizing and manipulating spatial features with geometry and attributes.
 *
 * Copyright (C) 2003 Vivid Solutions
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * For more information, contact:
 *
 * Vivid Solutions
 * Suite #1A
 * 2328 Government Street
 * Victoria BC  V8T 5G5
 * Canada
 *
 * (250)385-6040
 * www.vividsolutions.com
 */

package com.vividsolutions.jump.feature;

import java.util.*;


/**
 * Records update transactions on {@link Feature}s, and can apply them
 * to a {@link FeatureCollection}.
 */
public class FeatureUpdateRecorder {
    private Map updates = new HashMap();
    private int updateCount = 0;

    public FeatureUpdateRecorder() {
    }

    public void update(Feature origFeat, Feature newFeat) {
        updates.put(origFeat, new FeatureUpdate(origFeat, newFeat));
        updateCount++;
    }

    public int getCount() { return updateCount; }
    /**
     * Applies updates to an existing FeatureCollection.
     * The FeatureDataset returned will contain all the Features in the original
     * dataset which do not have updates, as well as the new versions of updated features
     */
    public FeatureDataset applyUpdates(FeatureCollection fc) {
        FeatureDataset fd = new FeatureDataset(fc.getFeatureSchema());

        for (Iterator i = fc.iterator(); i.hasNext();) {
            Feature f = (Feature) i.next();
            FeatureUpdate fu = (FeatureUpdate) updates.get(f);

            if (fu == null) {
                fd.add(f);
            } else {
                fd.add(fu.getNew());
            }
        }

        return fd;
    }
}