GeoJson: Improper Deserialization of Document with a GeoJsonPolygon [DATAMONGO-2664]

Bjorn Harvold opened DATAMONGO-2664 and commented

I’m trying to attach screenshots but getting “Try again. Invalid token”. Will try to attach after I create the ticket.

The existing test that accompanies Spring Data MongoDb is in the class called GeoJsonModuleUnitTests:

@Test // DATAMONGO-1181	public void shouldDeserializeGeoJsonPolygonCorrectly() throws JsonParseException, JsonMappingException, 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] ] ]}";
		assertThat(mapper.readValue(json, GeoJsonPolygon.class)).isEqualTo(new GeoJsonPolygon(				Arrays.asList(new Point(100, 0), new Point(101, 0), new Point(101, 1), new Point(100, 1), new Point(100, 0))));	}

And that passes just fine.

However, change those points to GeoJsonPoint objects and it fails:

@Test
public void shouldSerializeGeoJsonPolygonCorrectly() 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 GeoJsonPoint(100, 0), new GeoJsonPoint(101, 0), new GeoJsonPoint(101, 1), new GeoJsonPoint(100, 1), new GeoJsonPoint(100, 0));
    GeoJsonPolygon polygon = new GeoJsonPolygon(points);
    
    assertThat(mapper.readValue(json, GeoJsonPolygon.class)).isEqualTo(polygon);
    assertThat(mapper.writeValueAsString(polygon)).isEqualTo(json);
}

And that is exactly what happens when I query MongoDb (simple findById()) for a document with Spring Data MongoDb. When I look in the object graph, I see GeoJsonPoint objects as coordinates in my Polygon.

When the Jackson ObjectMapper serializes that data, it looks like this:

"polygon" : {
        "points" : [ {
          "x" : 105.44848312743373,
          "y" : 13.049959719225617,
          "type" : "Point",
          "coordinates" : [ 105.44848312743373, 13.049959719225617 ]
        }, {
          "x" : 105.11889328368373,
          "y" : 11.891452140925736,
          "type" : "Point",
          "coordinates" : [ 105.11889328368373, 11.891452140925736 ]
        }, {
          "x" : 105.69018234618373,
          "y" : 11.50415959858532,
          "type" : "Point",
          "coordinates" : [ 105.69018234618373, 11.50415959858532 ]
        }, {
          "x" : 105.88793625243373,
          "y" : 11.998936428709188,
          "type" : "Point",
          "coordinates" : [ 105.88793625243373, 11.998936428709188 ]
        }, {
          "x" : 106.81078781493373,
          "y" : 11.998936428709188,
          "type" : "Point",
          "coordinates" : [ 106.81078781493373, 11.998936428709188 ]
        }, {
          "x" : 107.29418625243373,
          "y" : 12.600046596262514,
          "type" : "Point",
          "coordinates" : [ 107.29418625243373, 12.600046596262514 ]
        }, {
          "x" : 107.22826828368373,
          "y" : 13.584502655549848,
          "type" : "Point",
          "coordinates" : [ 107.22826828368373, 13.584502655549848 ]
        }, {
          "x" : 106.48119797118373,
          "y" : 12.964324199217307,
          "type" : "Point",
          "coordinates" : [ 106.48119797118373, 12.964324199217307 ]
        }, {
          "x" : 106.41528000243373,
          "y" : 14.543620849640376,
          "type" : "Point",
          "coordinates" : [ 106.41528000243373, 14.543620849640376 ]
        } ],
        "coordinates" : [ {
          "type" : "LineString",
          "coordinates" : [ {
            "x" : 105.44848312743373,
            "y" : 13.049959719225617,
            "type" : "Point",
            "coordinates" : [ 105.44848312743373, 13.049959719225617 ]
          }, {
            "x" : 105.11889328368373,
            "y" : 11.891452140925736,
            "type" : "Point",
            "coordinates" : [ 105.11889328368373, 11.891452140925736 ]
          }, {
            "x" : 105.69018234618373,
            "y" : 11.50415959858532,
            "type" : "Point",
            "coordinates" : [ 105.69018234618373, 11.50415959858532 ]
          }, {
            "x" : 105.88793625243373,
            "y" : 11.998936428709188,
            "type" : "Point",
            "coordinates" : [ 105.88793625243373, 11.998936428709188 ]
          }, {
            "x" : 106.81078781493373,
            "y" : 11.998936428709188,
            "type" : "Point",
            "coordinates" : [ 106.81078781493373, 11.998936428709188 ]
          }, {
            "x" : 107.29418625243373,
            "y" : 12.600046596262514,
            "type" : "Point",
            "coordinates" : [ 107.29418625243373, 12.600046596262514 ]
          }, {
            "x" : 107.22826828368373,
            "y" : 13.584502655549848,
            "type" : "Point",
            "coordinates" : [ 107.22826828368373, 13.584502655549848 ]
          }, {
            "x" : 106.48119797118373,
            "y" : 12.964324199217307,
            "type" : "Point",
            "coordinates" : [ 106.48119797118373, 12.964324199217307 ]
          }, {
            "x" : 106.41528000243373,
            "y" : 14.543620849640376,
            "type" : "Point",
            "coordinates" : [ 106.41528000243373, 14.543620849640376 ]
          } ]
        } ],
        "type" : "Polygon"
      }

Please advise,

Bjorn

---

Affects: 3.1.1 (2020.0.1)

Attachments:

• GeoJsonPolygon_Document.png (343.80 kB)
• GeoJsonPolygon_Object.png (189.50 kB)

[bjornharvold]

Sure thing @christophstrobl. I’ll create a PR for you guys. I’ve already signed your CLA.

[bjornharvold]

Hi @jwill490

Have a look at the unit tests here: https://github.com/spring-projects/spring-data-mongodb/blob/main/spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/geo/GeoJsonSerializersUnitTests.java