Support for geospatial queries in Mongodb

[Timo Westkämper]

Related infos : http://www.mongodb.org/display/DOCS/Geospatial+Indexing

[Timo Westkämper (timo-westkamper)]

The support for the near-function has been made available via custom types

The MorphiaAnnotationProcessor declares a custom-type mapping from Double[] to Point like this :

  configuration.addCustomType(Double[].class, Point.class);

Now you can use Double arrays in your domain class and they will be mapped to the Point class :

@Entity
public class GeoEntity {

    private @Id ObjectId id;

    private Double[] location;

   // ...

}

The Point class provides the methods needed for "near" usage :

public class Point extends ArrayPath<Double>{

    public BooleanExpression near(double latVal, double longVal){
        return BooleanOperation.create(MongodbOps.NEAR, this, new ConstantImpl<Double[]>(new Double[]{latVal, longVal}));
    }

}

Here is a test case which demonstrates the usage :

    @Test
    public void Near(){
        ds.save(new GeoEntity(10.0, 50.0));
        ds.save(new GeoEntity(20.0, 50.0));
        ds.save(new GeoEntity(30.0, 50.0));

        List<GeoEntity> entities = query().where(geoEntity.location.near(50.0, 50.0)).list();
        assertEquals(30.0, entities.get(0).getLocation()[0].doubleValue(), 0.1);
        assertEquals(20.0, entities.get(1).getLocation()[0].doubleValue(), 0.1);
        assertEquals(10.0, entities.get(2).getLocation()[0].doubleValue(), 0.1);
    }

[Timo Westkämper (timo-westkamper)]

Released in 2.2.0-beta1