com.graphhopper.json.FeatureJsonDeserializer.java Source code

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Here is the source code for com.graphhopper.json.FeatureJsonDeserializer.java

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/*
 *  Licensed to GraphHopper GmbH under one or more contributor
 *  license agreements. See the NOTICE file distributed with this work for 
 *  additional information regarding copyright ownership.
 * 
 *  GraphHopper GmbH licenses this file to you 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 com.graphhopper.json;

import com.graphhopper.json.geo.JsonFeature;
import com.graphhopper.json.geo.Geometry;
import com.graphhopper.json.geo.Point;
import com.graphhopper.json.geo.LineString;
import com.google.gson.*;
import com.graphhopper.util.shapes.BBox;

import java.lang.reflect.Type;
import java.util.Map;
import java.util.UUID;

/**
 * This class makes reading the different geometry types possible for Gson.
 *
 * @author Peter Karich
 */
public class FeatureJsonDeserializer implements JsonDeserializer<JsonFeature> {
    @Override
    public JsonFeature deserialize(JsonElement json, Type type, JsonDeserializationContext context)
            throws JsonParseException {
        try {
            JsonObject obj = json.getAsJsonObject();
            String id, strType = null;
            Map<String, Object> properties = null;
            BBox bbox = null;
            Geometry geometry = null;

            // TODO ensure uniqueness
            if (obj.has("id"))
                id = obj.get("id").getAsString();
            else
                id = UUID.randomUUID().toString();

            if (obj.has("properties")) {
                properties = context.deserialize(obj.get("properties"), Map.class);
            }

            if (obj.has("bbox"))
                bbox = parseBBox(obj.get("bbox").getAsJsonArray());

            if (obj.has("geometry")) {
                JsonObject geometryJson = obj.get("geometry").getAsJsonObject();

                if (geometryJson.has("coordinates")) {
                    if (!geometryJson.has("type"))
                        throw new IllegalArgumentException("No type for non-empty coordinates specified");

                    strType = context.deserialize(geometryJson.get("type"), String.class);
                    if ("Point".equals(strType)) {
                        JsonArray arr = geometryJson.get("coordinates").getAsJsonArray();
                        double lon = arr.get(0).getAsDouble();
                        double lat = arr.get(1).getAsDouble();
                        if (arr.size() == 3)
                            geometry = new Point(lat, lon, arr.get(2).getAsDouble());
                        else
                            geometry = new Point(lat, lon);

                    } else if ("MultiPoint".equals(strType)) {
                        geometry = parseLineString(geometryJson);

                    } else if ("LineString".equals(strType)) {
                        geometry = parseLineString(geometryJson);

                    } else {
                        throw new IllegalArgumentException("Coordinates type " + strType + " not yet supported");
                    }
                }
            }

            return new JsonFeature(id, strType, bbox, geometry, properties);

        } catch (Exception ex) {
            throw new JsonParseException("Problem parsing JSON feature " + json);
        }
    }

    LineString parseLineString(JsonObject geometry) {
        JsonArray arr = geometry.get("coordinates").getAsJsonArray();
        boolean is3D = arr.size() == 0 || arr.get(0).getAsJsonArray().size() == 3;
        LineString lineString = new LineString(arr.size(), is3D);

        for (int i = 0; i < arr.size(); i++) {
            JsonArray pointArr = arr.get(i).getAsJsonArray();
            double lon = pointArr.get(0).getAsDouble();
            double lat = pointArr.get(1).getAsDouble();
            if (pointArr.size() == 3)
                lineString.add(lat, lon, pointArr.get(2).getAsDouble());
            else
                lineString.add(lat, lon);
        }
        return lineString;
    }

    private BBox parseBBox(JsonArray arr) {
        // The value of the bbox member must be a 2*n array where n is the number of dimensions represented 
        // in the contained geometries, with the lowest values for all axes followed by the highest values. 
        // The axes order of a bbox follows the axes order of geometries => lon,lat,ele
        if (arr.size() == 6) {
            double minLon = arr.get(0).getAsDouble();
            double minLat = arr.get(1).getAsDouble();
            double minEle = arr.get(2).getAsDouble();

            double maxLon = arr.get(3).getAsDouble();
            double maxLat = arr.get(4).getAsDouble();
            double maxEle = arr.get(5).getAsDouble();

            return new BBox(minLon, maxLon, minLat, maxLat, minEle, maxEle);

        } else if (arr.size() == 4) {
            double minLon = arr.get(0).getAsDouble();
            double minLat = arr.get(1).getAsDouble();

            double maxLon = arr.get(2).getAsDouble();
            double maxLat = arr.get(3).getAsDouble();

            return new BBox(minLon, maxLon, minLat, maxLat);
        } else {
            throw new IllegalArgumentException(
                    "Illegal array dimension (" + arr.size() + ") of bbox " + arr.toString());
        }
    }
}