org.maptalks.geojson.json.GeoJSONFactory Maven / Gradle / Ivy

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GeoJSON Serilization and mutual conversion with JSON .
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package org.maptalks.geojson.json;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import org.maptalks.geojson.*;

import java.util.HashMap;
import java.util.Map;

public class GeoJSONFactory {
    static Map geoJsonTypeMap = new HashMap();

    static {
        geoJsonTypeMap.put(GeoJSONTypes.TYPE_POINT,Point.class);
        geoJsonTypeMap.put(GeoJSONTypes.TYPE_LINESTRING,LineString.class);
        geoJsonTypeMap.put(GeoJSONTypes.TYPE_POLYGON,Polygon.class);
        geoJsonTypeMap.put(GeoJSONTypes.TYPE_MULTIPOINT,MultiPoint.class);
        geoJsonTypeMap.put(GeoJSONTypes.TYPE_MULTILINESTRING,MultiLineString.class);
        geoJsonTypeMap.put(GeoJSONTypes.TYPE_MULTIPOLYGON,MultiPolygon.class);
        geoJsonTypeMap.put(GeoJSONTypes.TYPE_GEOMETRYCOLLECTION,GeometryCollection.class);
    }

    public static GeoJSON create(String json) {
        JSONObject node = JSON.parseObject(json);
        return create(node);
    }

    /**
     * 将json解析为FeatureCollection数组
     * @param json
     * @return
     */
    public static FeatureCollection[] createFeatureCollectionArray(String json) {
        JSONArray node = JSON.parseArray(json);
        int size = node.size();
        FeatureCollection[] result = new FeatureCollection[size];
        for (int i = 0; i < size; i++) {
            if (node.get(i) == null) {
                result[i] = null;
                continue;
            }
            result[i] = ((FeatureCollection) create(((JSONObject) node.get(i))));
        }
        return result;
    }

    /**
     * 将json解析为Feature数组
     * @param json
     * @return
     */
    public static Feature[] createFeatureArray(String json) {
        JSONArray node = JSON.parseArray(json);
        int size = node.size();
        Feature[] result = new Feature[size];
        for (int i = 0; i < size; i++) {
            if (node.get(i) == null) {
                result[i] = null;
                continue;
            }
            GeoJSON geojson = create(((JSONObject) node.get(i)));
            if (geojson instanceof Geometry) {
                result[i] = new Feature(((Geometry) geojson));
            } else {
                result[i] = ((Feature) geojson);
            }
        }
        return result;
    }


    /**
     * 将json解析为Geometry数组
     * @param json
     * @return
     */
    public static Geometry[] createGeometryArray(String json) {
        JSONArray node = JSON.parseArray(json);

        int size = node.size();
        Geometry[] result = new Geometry[size];
        for (int i = 0; i < size; i++) {
            if (node.get(i) == null) {
                result[i] = null;
                continue;
            }
            GeoJSON geojson = create(((JSONObject) node.get(i)));
            if (geojson instanceof Feature) {
                result[i] = ((Feature) geojson).getGeometry();
            } else {
                result[i] = ((Geometry) geojson);
            }
        }
        return result;
    }

    private static GeoJSON create(JSONObject node) {
        String type = node.getString("type");
        if ("FeatureCollection".equals(type)) {
            return readFeatureCollection(node);
        } else if ("Feature".equals(type)) {
            return readFeature(node);
        } else {
            return readGeometry(node, type);
        }
    }

    private static FeatureCollection readFeatureCollection(JSONObject node) {

        JSONArray jFeatures = node.getJSONArray("features");
        if (jFeatures == null) {
            //return a empty FeatureCollection
            FeatureCollection result = new FeatureCollection();
            result.setFeatures(new Feature[0]);
            return result;
        }
        int size = jFeatures.size();
        Feature[] features = new Feature[size];
        for (int i=0;i