GLatLngBounds.java

/*
 *
 * ==============================================================================
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package wicket.contrib.gmap3.api;

import wicket.contrib.gmap3.js.Constructor;

import java.util.List;
import java.util.StringTokenizer;

/**
 * Represents an Google Maps API's <a href= "http://www.google.com/apis/maps/documentation/reference.html#GLatLngBounds"
 * >GLatLngBounds</a>.
 */
public class GLatLngBounds implements GValue {

    /**
     * Default serialVersionUID.
     */
    private static final long serialVersionUID = 1L;

    private GLatLng _sw;
    private GLatLng _ne;

    /**
     * Use subsequent calls to #extend to define the boundaries.
     */
    public GLatLngBounds() {

    }

    /**
     * Construct.
     *
     * @param sw
     * @param ne
     */
    public GLatLngBounds(final GLatLng sw, final GLatLng ne) {
        _sw = sw;
        _ne = ne;
    }

    public GLatLngBounds(final List<? extends GLatLng> list) {
        for (final GLatLng point : list) {
            extend(point);
        }
    }

    public GLatLngBounds extend(final GLatLng latLng) {
        if (_sw == null) {
            _sw = latLng;
            _ne = latLng;
        } else {
            final double s = Math.min(getS(), latLng.getLat());
            final double w = Math.min(getW(), latLng.getLng());
            final double n = Math.max(getN(), latLng.getLat());
            final double e = Math.max(getE(), latLng.getLng());
            _sw = new GLatLng(s, w);
            _ne = new GLatLng(n, e);
        }
        return this;
    }

    public GLatLng getSW() {
        return _sw;
    }

    public GLatLng getNE() {
        return _ne;
    }

    public GLatLng getCenter() {
        return new GLatLng((getS() + getN()) / 2, (getW() + getE()) / 2);
    }

    public double getS() {
        return _sw.getLat();
    }

    public double getN() {
        return _ne.getLat();
    }

    public double getW() {
        return _sw.getLng();
    }

    public double getE() {
        return _ne.getLng();
    }

    @Override
    public String toString() {
        return getJSconstructor();
    }

    /**
     * @see wicket.contrib.gmap.api.GValue#getJSconstructor()
     */
    @Override
    public String getJSconstructor() {
        return new Constructor("google.maps.LatLngBounds").add(_sw.getJSconstructor()).add(_ne.getJSconstructor())
                .toJS();
    }

    @Override
    public int hashCode() {
        return _sw.hashCode() ^ _ne.hashCode();
    }

    @Override
    public boolean equals(final Object obj) {
        if (obj instanceof GLatLngBounds) {
            final GLatLngBounds t = (GLatLngBounds)obj;
            return t._sw.equals(_sw) && t._ne.equals(_ne);
        }
        return false;
    }

    /**
     * ((37.34068368469045, -122.48519897460936), (37.72184917678752, -121.79855346679686))
     */
    public static GLatLngBounds parse(final String value) {
        StringTokenizer tokenizer;
        try {
            tokenizer = new StringTokenizer(value, "(, )");
        } catch (final NullPointerException e) {
            return null;
        }
        if (tokenizer.countTokens() != 4) {
            return null;
        }

        final GLatLng sw = new GLatLng(Float.valueOf(tokenizer.nextToken()), Float.valueOf(tokenizer.nextToken()));
        final GLatLng ne = new GLatLng(Float.valueOf(tokenizer.nextToken()), Float.valueOf(tokenizer.nextToken()));
        return new GLatLngBounds(sw, ne);
    }

    /**
     * Workaround for http://code.google.com/p/gmaps-api-issues/issues/detail?id=3117.
     * @param _getBounds
     * @return
     */
    public static GLatLngBounds mapToFitBounds(final GLatLngBounds bounds) {
        GLatLng sw = bounds.getSW();
        GLatLng ne = bounds.getNE();

        double s = sw.getLat();
        double w = sw.getLng();
        double n = ne.getLat();
        double e = ne.getLng();

        final double dlng = (w - e) / 2.;
        final double dlat = (s - n) / 2.;
        final double clng = (w + e) / 2.;
        final double clat = (s + n) / 2.;

        // work around a bug in google maps...///
        w = clng + dlng / 1.5;
        e = clng - dlng / 1.5;
        s = clat + dlat / 1.5;
        n = clat - dlat / 1.5;

        sw = new GLatLng(s,w);
        ne = new GLatLng(n,e);
        final GLatLngBounds correctedBounds = new GLatLngBounds(sw,ne);
        return correctedBounds;
    }

}