Relax requirement for GeoJsonMultiPoint construction allowing creation using a single point.

Only 1 point is required per GeoJson RFC and Mongo works just fine with 1 point as well.

Closes #3776
Original pull request: #3777.

Author: tinedel

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

@@ -28,6 +28,7 @@
  * {@link GeoJsonMultiPoint} is defined as list of {@link Point}s.
  *
  * @author Christoph Strobl
+ * @author Ivan Volzhev
  * @since 1.7
  * @see <a href="https://geojson.org/geojson-spec.html#multipoint">https://geojson.org/geojson-spec.html#multipoint</a>
  */
@@ -40,12 +41,12 @@ public class GeoJsonMultiPoint implements GeoJson<Iterable<Point>> {
 	/**
 	 * Creates a new {@link GeoJsonMultiPoint} for the given {@link Point}s.
 	 *
-	 * @param points points must not be {@literal null} and have at least 2 entries.
+	 * @param points points must not be {@literal null} and have at least 1 entry.
 	 */
 	public GeoJsonMultiPoint(List<Point> points) {
 
 		Assert.notNull(points, "Points must not be null.");
-		Assert.isTrue(points.size() >= 2, "Minimum of 2 Points required.");
+		Assert.isTrue(points.size() >= 1, "Minimum of 1 Point required.");
 
 		this.points = new ArrayList<Point>(points);
 	}
@@ -69,6 +70,19 @@ public GeoJsonMultiPoint(Point first, Point second, Point... others) {
 		this.points.addAll(Arrays.asList(others));
 	}
 
+	/**
+	 * Creates a new {@link GeoJsonMultiPoint} for the given {@link Point}.
+	 *
+	 * @param point must not be {@literal null}.
+	 */
+	public GeoJsonMultiPoint(Point point) {
+
+		Assert.notNull(point, "First point must not be null!");
+
+		this.points = new ArrayList<Point>();
+		this.points.add(point);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.mongodb.core.geo.GeoJson#getType()

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

@@ -63,6 +63,7 @@
 /**
  * @author Christoph Strobl
  * @author Mark Paluch
+ * @author Ivan Volzhev
  */
 @ExtendWith({ MongoClientExtension.class, SpringExtension.class })
 @ContextConfiguration
@@ -329,6 +330,21 @@ public void shouldSaveAndRetrieveDocumentWithGeoJsonMultiPointTypeCorrectly() {
 		assertThat(result.geoJsonMultiPoint).isEqualTo(obj.geoJsonMultiPoint);
 	}
 
+	@Test // DATAMONGO-3776
+	public void shouldSaveAndRetrieveDocumentWithGeoJsonMultiPointTypeWithOnePointCorrectly() {
+
+		DocumentWithPropertyUsingGeoJsonType obj = new DocumentWithPropertyUsingGeoJsonType();
+		obj.id = "geoJsonMultiPoint";
+		obj.geoJsonMultiPoint = new GeoJsonMultiPoint(new Point(0, 0));
+
+		template.save(obj);
+
+		DocumentWithPropertyUsingGeoJsonType result = template.findOne(query(where("id").is(obj.id)),
+				DocumentWithPropertyUsingGeoJsonType.class);
+
+		assertThat(result.geoJsonMultiPoint).isEqualTo(obj.geoJsonMultiPoint);
+	}
+
 	@Test // DATAMONGO-1137
 	public void shouldSaveAndRetrieveDocumentWithGeoJsonMultiPolygonTypeCorrectly() {