com.grublr.geo.s2.internal.S2Util.java Source code

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Here is the source code for com.grublr.geo.s2.internal.S2Util.java

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/*
 * Copyright 2010-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 * 
 *  http://aws.amazon.com/apache2.0
 * 
 * or in the "license" file accompanying this file. This file 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 com.grublr.geo.s2.internal;

import com.grublr.geo.model.GeoPoint;
import com.grublr.geo.model.GeoQueryRequest;
import com.grublr.geo.model.QueryRadiusRequest;
import com.grublr.geo.model.QueryRectangleRequest;
import com.google.common.geometry.S2LatLng;
import com.google.common.geometry.S2LatLngRect;

public class S2Util {

    /**
     * An utility method to get a bounding box of latitude and longitude from a given GeoQueryRequest.
     * 
     * @param geoQueryRequest
     *            It contains all of the necessary information to form a latitude and longitude box.
     * 
     * */
    public static S2LatLngRect getBoundingLatLngRect(GeoQueryRequest geoQueryRequest) {
        if (geoQueryRequest instanceof QueryRectangleRequest) {
            QueryRectangleRequest queryRectangleRequest = (QueryRectangleRequest) geoQueryRequest;

            GeoPoint minPoint = queryRectangleRequest.getMinPoint();
            GeoPoint maxPoint = queryRectangleRequest.getMaxPoint();

            S2LatLngRect latLngRect = null;

            if (minPoint != null && maxPoint != null) {
                S2LatLng minLatLng = S2LatLng.fromDegrees(minPoint.getLatitude(), minPoint.getLongitude());
                S2LatLng maxLatLng = S2LatLng.fromDegrees(maxPoint.getLatitude(), maxPoint.getLongitude());

                latLngRect = new S2LatLngRect(minLatLng, maxLatLng);
            }

            return latLngRect;
        } else if (geoQueryRequest instanceof QueryRadiusRequest) {
            QueryRadiusRequest queryRadiusRequest = (QueryRadiusRequest) geoQueryRequest;

            GeoPoint centerPoint = queryRadiusRequest.getCenterPoint();
            double radiusInMeter = queryRadiusRequest.getRadiusInMeter();

            S2LatLng centerLatLng = S2LatLng.fromDegrees(centerPoint.getLatitude(), centerPoint.getLongitude());

            double latReferenceUnit = centerPoint.getLatitude() > 0.0 ? -1.0 : 1.0;
            S2LatLng latReferenceLatLng = S2LatLng.fromDegrees(centerPoint.getLatitude() + latReferenceUnit,
                    centerPoint.getLongitude());
            double lngReferenceUnit = centerPoint.getLongitude() > 0.0 ? -1.0 : 1.0;
            S2LatLng lngReferenceLatLng = S2LatLng.fromDegrees(centerPoint.getLatitude(),
                    centerPoint.getLongitude() + lngReferenceUnit);

            double latForRadius = radiusInMeter / centerLatLng.getEarthDistance(latReferenceLatLng);
            double lngForRadius = radiusInMeter / centerLatLng.getEarthDistance(lngReferenceLatLng);

            S2LatLng minLatLng = S2LatLng.fromDegrees(centerPoint.getLatitude() - latForRadius,
                    centerPoint.getLongitude() - lngForRadius);
            S2LatLng maxLatLng = S2LatLng.fromDegrees(centerPoint.getLatitude() + latForRadius,
                    centerPoint.getLongitude() + lngForRadius);

            return new S2LatLngRect(minLatLng, maxLatLng);
        }

        return null;
    }
}