FeatureDataset.java

/*
 * 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.*;

import com.vividsolutions.jts.geom.Envelope;


/**
 * Basic implementation of FeatureCollection.
 */
public class FeatureDataset implements FeatureCollection {
    private FeatureSchema featureSchema;

    //<<TODO>> Possibly use hashtable to do spatial indexing [Jon Aquino]
    private ArrayList features;
    private Envelope envelope = null;

    /**
     * Creates a FeatureDataset, initialized with a group of Features.
     * @param newFeatures an initial group of features to add to this FeatureDataset
     * @param featureSchema the types of the attributes of the features in this collection
     */
    public FeatureDataset(Collection newFeatures, FeatureSchema featureSchema) {
        features = new ArrayList(newFeatures);
        this.featureSchema = featureSchema;
    }

    /**
     * Creates a FeatureDataset.
     * @param featureSchema the types of the attributes of the features in this collection
     */
    public FeatureDataset(FeatureSchema featureSchema) {
        this(new ArrayList(), featureSchema);
    }

    public Feature getFeature(int index) {
        return (Feature) features.get(index);
    }

    public FeatureSchema getFeatureSchema() {
        return featureSchema;
    }

    /**
     * Because the envelope is cached, the envelope may be incorrect if you
     * later change a Feature's geometry using Feature#setGeometry.
     */
    public Envelope getEnvelope() {
        if (envelope == null) {
            envelope = new Envelope();

            for (Iterator i = features.iterator(); i.hasNext();) {
                Feature feature = (Feature) i.next();
                envelope.expandToInclude(feature.getGeometry()
                                                .getEnvelopeInternal());
            }
        }

        return envelope;
    }

    public List getFeatures() {
        return Collections.unmodifiableList(features);
    }

    public boolean isEmpty() {
        return size() == 0;
    }

    /**
     *@return    a List containing the features whose envelopes intersect the
     *      given envelope
     */

    //<<TODO:DESIGN>> Perhaps return value should be a Set, not a List, because order
    //doesn't matter. [Jon Aquino]
    public List query(Envelope envelope) {
        if (!envelope.intersects(getEnvelope())) {
            return new ArrayList();
        }

        //<<TODO:NAMING>> Rename this method to getFeatures(Envelope), to parallel
        //getFeatures() [Jon Aquino]
        ArrayList queryResult = new ArrayList();

        for (Iterator i = features.iterator(); i.hasNext();) {
            Feature feature = (Feature) i.next();

            if (feature.getGeometry().getEnvelopeInternal().intersects(envelope)) {
                queryResult.add(feature);
            }
        }

        return queryResult;
    }

    public void add(Feature feature) {
        features.add(feature);
        if (envelope != null) {
            envelope.expandToInclude(feature.getGeometry().getEnvelopeInternal());
        }
    }

    /**
     * Returns whether or not this Feature is in this collection
     * @return true if this feature is in this collection, as determined using
     * Feature#equals
     */
    public boolean contains(Feature feature) {
        return features.contains(feature);
    }

    /**
     * Removes the features which intersect the given envelope
     * @param env
     */
    public Collection remove(Envelope env) {
        Collection features = query(env);
        removeAll(features);

        return features;
    }

    public void remove(Feature feature) {
        features.remove(feature);
        invalidateEnvelope();
    }

    /**
     * Removes all features from this collection.
     */
    public void clear() {
        invalidateEnvelope();
        features.clear();
    }

    public int size() {
        return features.size();
    }

    public Iterator iterator() {
        return features.iterator();
    }

    public void invalidateEnvelope() {
        envelope = null;
    }

    public void addAll(Collection features) {
        this.features.addAll(features);
        if (envelope != null) {
            for (Iterator i = features.iterator(); i.hasNext(); ) {
                Feature feature = (Feature) i.next();
                envelope.expandToInclude(feature.getGeometry().getEnvelopeInternal());
            }            
        }
    }

    public void removeAll(Collection features) {
        this.features.removeAll(features);
        invalidateEnvelope();
    }
}