Added a serializers module to all GeoJson types with unit tests.

Original pull request: #3539.
Closes #3517

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/geo/GeoJsonSerializersModule.java

@@ -0,0 +1,156 @@
+/*
+ * Copyright 2015-2021 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.data.mongodb.core.geo;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.Module;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import org.springframework.data.geo.Point;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A Jackson {@link Module} to register custom {@link JsonSerializer}s for GeoJSON types.
+ *
+ * @author Bjorn Harvold
+ * @since 
+ */
+public class GeoJsonSerializersModule extends SimpleModule {
+
+	private static final long serialVersionUID = 1340494654898895610L;
+
+	public GeoJsonSerializersModule() {
+		addSerializer(GeoJsonPoint.class, new GeoJsonPointSerializer());
+		addSerializer(GeoJsonMultiPoint.class, new GeoJsonMultiPointSerializer());
+		addSerializer(GeoJsonLineString.class, new GeoJsonLineStringSerializer());
+		addSerializer(GeoJsonMultiLineString.class, new GeoJsonMultiLineStringSerializer());
+		addSerializer(GeoJsonPolygon.class, new GeoJsonPolygonSerializer());
+		addSerializer(GeoJsonMultiPolygon.class, new GeoJsonMultiPolygonSerializer());
+	}
+
+	public static class GeoJsonPointSerializer extends JsonSerializer<GeoJsonPoint> {
+		@Override
+		public void serialize(GeoJsonPoint value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
+			gen.writeStartObject();
+			gen.writeStringField("type", value.getType());
+			gen.writeObjectField("coordinates", value.getCoordinates());
+			gen.writeEndObject();
+		}
+
+	}
+
+	public static class GeoJsonLineStringSerializer extends JsonSerializer<GeoJsonLineString> {
+
+		@Override
+		public void serialize(GeoJsonLineString value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
+			gen.writeStartObject();
+			gen.writeStringField("type", value.getType());
+			gen.writeArrayFieldStart("coordinates");
+			for (Point p : value.getCoordinates()) {
+				gen.writeObject(new double[]{p.getX(), p.getY()});
+			}
+			gen.writeEndArray();
+			gen.writeEndObject();
+		}
+	}
+
+	public static class GeoJsonMultiPointSerializer extends JsonSerializer<GeoJsonMultiPoint> {
+
+		@Override
+		public void serialize(GeoJsonMultiPoint value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
+			gen.writeStartObject();
+			gen.writeStringField("type", value.getType());
+			gen.writeArrayFieldStart("coordinates");
+			for (Point p : value.getCoordinates()) {
+				gen.writeObject(new double[]{p.getX(), p.getY()});
+			}
+			gen.writeEndArray();
+			gen.writeEndObject();
+		}
+	}
+
+	public static class GeoJsonMultiLineStringSerializer extends JsonSerializer<GeoJsonMultiLineString> {
+
+		@Override
+		public void serialize(GeoJsonMultiLineString value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
+			gen.writeStartObject();
+			gen.writeStringField("type", value.getType());
+			gen.writeArrayFieldStart("coordinates");
+			for (GeoJsonLineString lineString : value.getCoordinates()) {
+				List<double[]> arrayList = new ArrayList<>();
+				for (Point p : lineString.getCoordinates()) {
+					arrayList.add(new double[]{p.getX(), p.getY()});
+				}
+				double[][] doubles = arrayList.toArray(new double[0][0]);
+				gen.writeObject(doubles);
+			}
+			gen.writeEndArray();
+			gen.writeEndObject();
+		}
+	}
+
+	public static class GeoJsonPolygonSerializer extends JsonSerializer<GeoJsonPolygon> {
+
+		@Override
+		public void serialize(GeoJsonPolygon value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
+			gen.writeStartObject();
+			gen.writeStringField("type", value.getType());
+			gen.writeArrayFieldStart("coordinates");
+			for (GeoJsonLineString ls : value.getCoordinates()) {
+				gen.writeStartArray();
+				for (Point p : ls.getCoordinates()) {
+					gen.writeObject(new double[]{p.getX(), p.getY()});
+				}
+				gen.writeEndArray();
+			}
+			gen.writeEndArray();
+			gen.writeEndObject();
+		}
+	}
+
+	public static class GeoJsonMultiPolygonSerializer extends JsonSerializer<GeoJsonMultiPolygon> {
+
+		@Override
+		public void serialize(GeoJsonMultiPolygon value, JsonGenerator gen, SerializerProvider serializers) throws IOException, JsonProcessingException {
+			gen.writeStartObject();
+			gen.writeStringField("type", value.getType());
+			gen.writeArrayFieldStart("coordinates");
+			for (GeoJsonPolygon polygon : value.getCoordinates()) {
+
+				gen.writeStartArray();
+
+				gen.writeStartArray();
+				for (GeoJsonLineString lineString : polygon.getCoordinates()) {
+
+					for (Point p : lineString.getCoordinates()) {
+						gen.writeObject(new double[]{p.getX(), p.getY()});
+					}
+
+				}
+
+				gen.writeEndArray();
+				gen.writeEndArray();
+			}
+			gen.writeEndArray();
+			gen.writeEndObject();
+		}
+	}
+}

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/geo/GeoJsonModuleRoundTripUnitTests.java

@@ -0,0 +1,151 @@
+/*
+ * Copyright 2015-2021 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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.springframework.data.mongodb.core.geo;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.data.geo.Point;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Bjorn Harvold
+ */
+public class GeoJsonModuleRoundTripUnitTests {
+
+	ObjectMapper mapper;
+
+	@BeforeEach
+	public void setUp() {
+
+		mapper = new ObjectMapper();
+		mapper.registerModule(new GeoJsonModule());
+		mapper.registerModule(new GeoJsonSerializersModule());
+	}
+
+	@Test
+	public void shouldMarshalJsonPointCorrectly() throws IOException {
+
+		String json = "{\"type\":\"Point\",\"coordinates\":[10.0,20.0]}";
+		GeoJsonPoint point = new GeoJsonPoint(10D, 20D);
+
+		assertThat(mapper.readValue(json, GeoJsonPoint.class)).isEqualTo(point);
+
+		String backToJSON =  mapper.writeValueAsString(point);
+
+		assertThat(backToJSON).isEqualTo(json);
+	}
+
+	@Test
+	public void shouldMarshalGeoJsonLineStringCorrectly()
+			throws IOException {
+
+		String json = "{\"type\":\"LineString\",\"coordinates\":[[10.0,20.0],[30.0,40.0],[50.0,60.0]]}";
+
+		GeoJsonLineString lineString = new GeoJsonLineString(Arrays.asList(new Point(10, 20), new Point(30, 40), new Point(50, 60)));
+
+		assertThat(mapper.readValue(json, GeoJsonLineString.class)).isEqualTo(lineString);
+
+		String backToJSON =  mapper.writeValueAsString(lineString);
+
+		assertThat(backToJSON).isEqualTo(json);
+	}
+
+	@Test
+	public void shouldMarshalGeoJsonMultiPointCorrectly() throws IOException {
+
+		String json = "{\"type\":\"MultiPoint\",\"coordinates\":[[10.0,20.0],[30.0,40.0],[50.0,60.0]]}";
+		GeoJsonMultiPoint multiPoint = new GeoJsonMultiPoint(Arrays.asList(new Point(10, 20), new Point(30, 40), new Point(50, 60)));
+
+		assertThat(mapper.readValue(json, GeoJsonMultiPoint.class)).isEqualTo(multiPoint);
+
+		String backToJSON =  mapper.writeValueAsString(multiPoint);
+
+		assertThat(backToJSON).isEqualTo(json);
+	}
+
+	@Test
+	@SuppressWarnings("unchecked")
+	public void shouldMarshalGeoJsonMultiLineStringCorrectly() throws IOException {
+
+		String json = "{\"type\":\"MultiLineString\",\"coordinates\":[[[10.0,20.0],[30.0,40.0]],[[50.0,60.0],[70.0,80.0]]]}";
+		GeoJsonMultiLineString multiLineString = new GeoJsonMultiLineString(Arrays.asList(new Point(10, 20), new Point(30, 40)), Arrays.asList(new Point(50, 60), new Point(70, 80)));
+
+		assertThat(mapper.readValue(json, GeoJsonMultiLineString.class)).isEqualTo(multiLineString);
+
+		String backToJSON =  mapper.writeValueAsString(multiLineString);
+
+		assertThat(backToJSON).isEqualTo(json);
+	}
+
+	@Test
+	public void shouldMarshalGeoJsonPolygonCorrectly() throws IOException {
+		String json = "{\"type\":\"Polygon\",\"coordinates\":[[[100.0,0.0],[101.0,0.0],[101.0,1.0],[100.0,1.0],[100.0,0.0]]]}";
+
+		List<Point> points = Arrays.asList(new Point(100, 0), new Point(101, 0), new Point(101, 1), new Point(100, 1), new Point(100, 0));
+		GeoJsonPolygon polygon = new GeoJsonPolygon(points);
+
+		assertThat(mapper.readValue(json, GeoJsonPolygon.class)).isEqualTo(polygon);
+
+		String backToJSON =  mapper.writeValueAsString(polygon);
+
+		assertThat(backToJSON).isEqualTo(json);
+	}
+
+	@Test
+	public void shouldMarshalGeoJsonMultiPolygonCorrectly()
+			throws IOException {
+
+		String json = "{\"type\":\"MultiPolygon\",\"coordinates\":["
+				+ "["
+				+ "["
+				+ "[102.0,2.0],[103.0,2.0],[103.0,3.0],[102.0,3.0],[102.0,2.0]"
+				+ "]"
+				+ "],"
+				+ "["
+				+ "["
+				+ "[100.0,0.0],[101.0,0.0],[101.0,1.0],[100.0,1.0],[100.0,0.0]"
+				+ "]"
+				+ "],"
+				+ "["
+				+ "["
+				+ "[100.2,0.2],[100.8,0.2],[100.8,0.8],[100.2,0.8],[100.2,0.2]"
+				+ "]"
+				+ "]"
+				+ "]"
+				+ "}";
+
+		GeoJsonMultiPolygon multiPolygon = new GeoJsonMultiPolygon(Arrays.asList(
+				new GeoJsonPolygon(Arrays.asList(new Point(102, 2), new Point(103, 2), new Point(103, 3), new Point(102, 3),
+						new Point(102, 2))),
+				new GeoJsonPolygon(Arrays.asList(new Point(100, 0), new Point(101, 0), new Point(101, 1), new Point(100, 1),
+						new Point(100, 0))),
+				new GeoJsonPolygon(Arrays.asList(new Point(100.2, 0.2), new Point(100.8, 0.2), new Point(100.8, 0.8),
+						new Point(100.2, 0.8), new Point(100.2, 0.2)))));
+
+		assertThat(mapper.readValue(json, GeoJsonMultiPolygon.class)).isEqualTo(multiPolygon);
+
+		String backToJSON =  mapper.writeValueAsString(multiPolygon);
+
+		assertThat(backToJSON).isEqualTo(json);
+
+	}
+}