Geo: Refactors libs/geo parser to provide serialization logic as well

server/src/main/java/org/elasticsearch/common/geo/GeometryFormat.java

@@ -0,0 +1,45 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch 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 org.elasticsearch.common.geo;
+
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.geo.geometry.Geometry;
+
+import java.io.IOException;
+import java.text.ParseException;
+
+/**
+ * Geometry serializer/deserializer
+ */
+public interface GeometryFormat {
+
+    /**
+     * Parser JSON representation of a geometry
+     */
+    Geometry fromXContent(XContentParser parser) throws IOException, ParseException;
+
+    /**
+     * Serializes the geometry into its JSON representation
+     */
+    XContentBuilder toXContent(Geometry geometry, XContentBuilder builder, ToXContent.Params params) throws IOException;
+
+}

server/src/main/java/org/elasticsearch/common/geo/GeometryParser.java

@@ -20,6 +20,8 @@
 package org.elasticsearch.common.geo;
 
 import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.geo.geometry.Geometry;
 import org.elasticsearch.geo.utils.GeographyValidator;
@@ -47,14 +49,64 @@ public GeometryParser(boolean rightOrientation, boolean coerce, boolean ignoreZV
     /**
      * Parses supplied XContent into Geometry
      */
-    public Geometry parse(XContentParser parser) throws IOException,
-        ParseException {
+    public Geometry parse(XContentParser parser) throws IOException, ParseException {
+        return geometryFormat(parser).fromXContent(parser);
+    }
+
+    /**
+     * Returns a geometry format object that can parse and then serialize the object back to the same format.
+     */
+    public GeometryFormat geometryFormat(XContentParser parser) {
         if (parser.currentToken() == XContentParser.Token.VALUE_NULL) {
-            return null;
+            return new GeometryFormat() {
+                @Override
+                public Geometry fromXContent(XContentParser parser) throws IOException {
+                    return null;
+                }
+
+                @Override
+                public XContentBuilder toXContent(Geometry geometry, XContentBuilder builder, ToXContent.Params params) throws IOException {
+                    if (geometry != null) {
+                        // We don't know the format of the original geometry - so going with default
+                        return GeoJson.toXContent(geometry, builder, params);
+                    } else {
+                        return builder.nullValue();
+                    }
+                }
+            };
         } else if (parser.currentToken() == XContentParser.Token.START_OBJECT) {
-            return geoJsonParser.fromXContent(parser);
+            return new GeometryFormat() {
+                @Override
+                public Geometry fromXContent(XContentParser parser) throws IOException {
+                    return geoJsonParser.fromXContent(parser);
+                }
+
+                @Override
+                public XContentBuilder toXContent(Geometry geometry, XContentBuilder builder, ToXContent.Params params) throws IOException {
+                    if (geometry != null) {
+                        return GeoJson.toXContent(geometry, builder, params);
+                    } else {
+                        return builder.nullValue();
+                    }
+                }
+            };
         } else if (parser.currentToken() == XContentParser.Token.VALUE_STRING) {
-            return wellKnownTextParser.fromWKT(parser.text());
+            return new GeometryFormat() {
+                @Override
+                public Geometry fromXContent(XContentParser parser) throws IOException, ParseException {
+                    return wellKnownTextParser.fromWKT(parser.text());
+                }
+
+                @Override
+                public XContentBuilder toXContent(Geometry geometry, XContentBuilder builder, ToXContent.Params params) throws IOException {
+                    if (geometry != null) {
+                        return builder.value(wellKnownTextParser.toWKT(geometry));
+                    } else {
+                        return builder.nullValue();
+                    }
+                }
+            };
+
         }
         throw new ElasticsearchParseException("shape must be an object consisting of type and coordinates");
     }

server/src/test/java/org/elasticsearch/common/geo/GeometryParserTests.java

@@ -20,6 +20,8 @@
 package org.elasticsearch.common.geo;
 
 import org.elasticsearch.ElasticsearchParseException;
+import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentParseException;
@@ -44,7 +46,11 @@ public void testGeoJsonParsing() throws Exception {
 
         try (XContentParser parser = createParser(pointGeoJson)) {
             parser.nextToken();
-            assertEquals(new Point(0, 100), new GeometryParser(true, randomBoolean(), randomBoolean()).parse(parser));
+            GeometryFormat format = new GeometryParser(true, randomBoolean(), randomBoolean()).geometryFormat(parser);
+            assertEquals(new Point(0, 100), format.fromXContent(parser));
+            XContentBuilder newGeoJson = XContentFactory.jsonBuilder();
+            format.toXContent(new Point(10, 100), newGeoJson, ToXContent.EMPTY_PARAMS);
+            assertEquals("{\"type\":\"Point\",\"coordinates\":[100.0,10.0]}", Strings.toString(newGeoJson));
         }
 
         XContentBuilder pointGeoJsonWithZ = XContentFactory.jsonBuilder()
@@ -77,7 +83,7 @@ public void testGeoJsonParsing() throws Exception {
                     .endArray()
                 .endObject();
 
-        Polygon p = new Polygon(new LinearRing(new double[] {1d, 1d, 0d, 0d, 1d}, new double[] {100d, 101d, 101d, 100d, 100d}));
+        Polygon p = new Polygon(new LinearRing(new double[]{1d, 1d, 0d, 0d, 1d}, new double[]{100d, 101d, 101d, 100d, 100d}));
         try (XContentParser parser = createParser(polygonGeoJson)) {
             parser.nextToken();
             // Coerce should automatically close the polygon
@@ -101,7 +107,12 @@ public void testWKTParsing() throws Exception {
             parser.nextToken(); // Start object
             parser.nextToken(); // Field Name
             parser.nextToken(); // Field Value
-            assertEquals(new Point(0, 100), new GeometryParser(true, randomBoolean(), randomBoolean()).parse(parser));
+            GeometryFormat format = new GeometryParser(true, randomBoolean(), randomBoolean()).geometryFormat(parser);
+            assertEquals(new Point(0, 100), format.fromXContent(parser));
+            XContentBuilder newGeoJson = XContentFactory.jsonBuilder().startObject().field("val");
+            format.toXContent(new Point(10, 100), newGeoJson, ToXContent.EMPTY_PARAMS);
+            newGeoJson.endObject();
+            assertEquals("{\"val\":\"point (100.0 10.0)\"}", Strings.toString(newGeoJson));
         }
     }
 
@@ -115,7 +126,20 @@ public void testNullParsing() throws Exception {
             parser.nextToken(); // Start object
             parser.nextToken(); // Field Name
             parser.nextToken(); // Field Value
-            assertNull(new GeometryParser(true, randomBoolean(), randomBoolean()).parse(parser));
+            GeometryFormat format = new GeometryParser(true, randomBoolean(), randomBoolean()).geometryFormat(parser);
+            assertNull(format.fromXContent(parser));
+
+            XContentBuilder newGeoJson = XContentFactory.jsonBuilder().startObject().field("val");
+            // if we serialize non-null value - it should be serialized as geojson
+            format.toXContent(new Point(10, 100), newGeoJson, ToXContent.EMPTY_PARAMS);
+            newGeoJson.endObject();
+            assertEquals("{\"val\":{\"type\":\"Point\",\"coordinates\":[100.0,10.0]}}", Strings.toString(newGeoJson));
+
+            newGeoJson = XContentFactory.jsonBuilder().startObject().field("val");
+            format.toXContent(null, newGeoJson, ToXContent.EMPTY_PARAMS);
+            newGeoJson.endObject();
+            assertEquals("{\"val\":null}", Strings.toString(newGeoJson));
+
         }
     }