Java tutorial
/** * Copyright 2013 OpenSocial Foundation * Copyright 2013 International Business Machines Corporation * * 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. * * Utility library for working with Activity Streams Actions * Requires underscorejs. * * @author James M Snell (jasnell@us.ibm.com) */ package com.ibm.common.geojson.as2; import static com.google.common.base.Preconditions.checkArgument; import java.lang.reflect.Type; import java.util.Arrays; import java.util.Map; import com.google.common.base.Enums; import com.google.gson.JsonDeserializationContext; import com.google.gson.JsonElement; import com.google.gson.JsonObject; import com.google.gson.JsonParseException; import com.google.gson.JsonPrimitive; import com.google.gson.JsonSerializationContext; import com.ibm.common.activitystreams.internal.Adapter; import com.ibm.common.geojson.BoundingBox; import com.ibm.common.geojson.CRS; import com.ibm.common.geojson.Feature; import com.ibm.common.geojson.FeatureCollection; import com.ibm.common.geojson.GeoMakers; import com.ibm.common.geojson.GeoObject; import com.ibm.common.geojson.Geometry; import com.ibm.common.geojson.Geometry.CoordinateGeometry; import com.ibm.common.geojson.GeometryCollection; import com.ibm.common.geojson.LineString; import com.ibm.common.geojson.MultiLineString; import com.ibm.common.geojson.MultiPoint; import com.ibm.common.geojson.MultiPolygon; import com.ibm.common.geojson.Point; import com.ibm.common.geojson.Polygon; import com.ibm.common.geojson.Position; @SuppressWarnings("rawtypes") public class GeoAdapter extends Adapter<GeoObject> { @Override public JsonElement serialize(GeoObject geo, Type type, JsonSerializationContext context) { JsonObject obj = new JsonObject(); obj.add("type", context.serialize(geo.type(), GeoObject.Type.class)); switch (geo.type()) { case POINT: case MULTIPOINT: case LINESTRING: case MULTILINESTRING: case MULTIPOLYGON: case POLYGON: CoordinateGeometry c = (CoordinateGeometry) geo; obj.add("coordinates", context.serialize(c.coordinates(), Iterable.class)); break; case GEOMETRYCOLLECTION: GeometryCollection gc = (GeometryCollection) geo; obj.add("geometries", context.serialize(gc.geometries(), Iterable.class)); break; case FEATURE: Feature feature = (Feature) geo; if (feature.id() != null) obj.addProperty("id", feature.id()); Geometry<?, ?> geometry = feature.geometry(); Map<String, Object> properties = feature.properties(); if (geometry != null) obj.add("geometry", context.serialize(feature.geometry())); if (properties != null) obj.add("properties", context.serialize(properties)); break; case FEATURECOLLECTION: FeatureCollection fc = (FeatureCollection) geo; obj.add("features", context.serialize(fc.features(), Iterable.class)); break; default: break; } if (geo.boundingBox() != null) { BoundingBox bb = geo.boundingBox(); obj.add("bbox", context.serialize(bb, Iterable.class)); } if (geo.crs() != null) { CRS crs = geo.crs(); JsonObject crsobj = new JsonObject(); crsobj.addProperty("name", crs.type()); if (crs.size() > 0) crsobj.add("properties", context.serialize(crs.properties())); obj.add("crs", crsobj); } return obj; } private Position toPosition(float[] pos) { Position.Builder b = new Position.Builder(); for (int n = 0; n < pos.length; n++) { if (n == 0) b.northing(pos[n]); else if (n == 1) b.easting(pos[n]); else if (n == 2) b.altitude(pos[n]); else b.additional(pos[n]); } return b.get(); } @Override public GeoObject deserialize(JsonElement element, Type type, JsonDeserializationContext context) throws JsonParseException { GeoObject.Builder geo = null; checkArgument(element.isJsonObject()); JsonObject obj = element.getAsJsonObject(); checkArgument(obj.has("type")); GeoObject.Type et = Enums.getIfPresent(GeoObject.Type.class, obj.get("type").getAsString().toUpperCase()) .orNull(); checkArgument(et != null); switch (et) { case FEATURE: geo = GeoMakers.feature(); break; case FEATURECOLLECTION: geo = GeoMakers.featureCollection(); type = Feature.class; break; case GEOMETRYCOLLECTION: geo = GeoMakers.geometryCollection(); type = Geometry.class; break; case LINESTRING: geo = GeoMakers.linestring(); type = Position.class; break; case MULTILINESTRING: geo = GeoMakers.multiLineString(); type = LineString.class; break; case MULTIPOINT: geo = GeoMakers.multipoint(); type = Position.class; break; case MULTIPOLYGON: geo = GeoMakers.multiPolygon(); type = Polygon.class; break; case POINT: geo = GeoMakers.point(); type = null; break; case POLYGON: geo = GeoMakers.polygon(); type = LineString.class; break; } for (Map.Entry<String, JsonElement> entry : obj.entrySet()) { JsonElement el = entry.getValue(); String name = entry.getKey(); if ("crs".equals(name)) { CRS.Builder cb = new CRS.Builder(); JsonObject o = el.getAsJsonObject(); if (o.has("type")) cb.type(o.get("type").getAsString()); if (o.has("properties")) { JsonObject p = o.get("properties").getAsJsonObject(); for (Map.Entry<String, JsonElement> e : p.entrySet()) { cb.set(e.getKey(), context.deserialize(e.getValue(), Object.class)); } } geo.crs(cb.get()); } else if ("properties".equals(name)) { geo.set("properties", context.deserialize(el, Map.class)); } else if ("bbox".equals(name)) { BoundingBox.Builder bb = new BoundingBox.Builder(); float[] points = context.deserialize(el, float[].class); bb.add(points); geo.boundingBox(bb.get()); } else if ("features".equals(name)) { Feature[] features = context.deserialize(el, Feature[].class); FeatureCollection.Builder fcb = (FeatureCollection.Builder) geo; for (Feature f : features) fcb.add(f); } else if ("coordinates".equals(name)) { switch (et) { case LINESTRING: { LineString.Builder lsb = (LineString.Builder) geo; float[][] positions = context.deserialize(el, float[][].class); boolean ring = ring(positions); if (ring) lsb.linearRing(); for (int n = 0; n < positions.length; n++) { if (!ring || (ring && n < positions.length - 1)) lsb.add(toPosition(positions[n])); } break; } case MULTIPOINT: { MultiPoint.Builder lsb = (MultiPoint.Builder) geo; float[][] positions = context.deserialize(el, float[][].class); for (float[] pos : positions) lsb.add(toPosition(pos)); break; } case MULTILINESTRING: { MultiLineString.Builder mlb = (MultiLineString.Builder) geo; float[][][] positions = context.deserialize(el, float[][][].class); for (float[][] lines : positions) { LineString.Builder lsb = GeoMakers.linestring(); boolean ring = ring(lines); if (ring) lsb.linearRing(); for (int n = 0; n < lines.length; n++) { if (!ring || (ring && n < lines.length - 1)) lsb.add(toPosition(lines[n])); } for (float[] pos : lines) lsb.add(toPosition(pos)); mlb.add(lsb); } break; } case POLYGON: { Polygon.Builder mlb = (Polygon.Builder) geo; float[][][] positions = context.deserialize(el, float[][][].class); for (float[][] lines : positions) { LineString.Builder lsb = GeoMakers.linestring(); for (float[] pos : lines) lsb.add(toPosition(pos)); mlb.add(lsb); } break; } case MULTIPOLYGON: { MultiPolygon.Builder mpb = (MultiPolygon.Builder) geo; float[][][][] positions = context.deserialize(el, float[][][][].class); for (float[][][] polygons : positions) { Polygon.Builder pb = GeoMakers.polygon(); for (float[][] lines : polygons) { LineString.Builder lsb = GeoMakers.linestring(); for (float[] pos : lines) lsb.add(toPosition(pos)); pb.add(lsb); } mpb.add(pb); } break; } case POINT: Point.Builder pb = (Point.Builder) geo; float[] position = context.deserialize(el, float[].class); pb.position(toPosition(position)); break; default: break; } } else if ("geometries".equals(name)) { Geometry[] geos = context.deserialize(el, Geometry[].class); GeometryCollection.Builder fcb = (GeometryCollection.Builder) geo; for (Geometry<?, ?> g : geos) fcb.add(g); } else { if (el.isJsonArray()) { geo.set(name, context.deserialize(el, Object.class)); } else if (el.isJsonObject()) { geo.set(name, context.deserialize(el, GeoObject.class)); } else if (el.isJsonPrimitive()) { JsonPrimitive p = el.getAsJsonPrimitive(); if (p.isBoolean()) geo.set(name, p.getAsBoolean()); else if (p.isNumber()) geo.set(name, p.getAsNumber()); else if (p.isString()) geo.set(name, p.getAsString()); } } } return geo.get(); } private static boolean ring(float[][] line) { return ring(first(line), last(line)); } private static boolean ring(float[] p1, float[] p2) { return Arrays.equals(p1, p2); } private static float[] first(float[][] line) { if (line.length == 0) return null; return line[0]; } private static float[] last(float[][] line) { if (line.length == 0) return null; return line[line.length - 1]; } }