JtsShapeFactory MultipolygonBuilder fails to validate shape #219

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1. dsmiley commented on Mar 13, 2022

   

   dsmiley

   on Mar 13, 2022

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   Garbage in, Garbage out -- no? Maybe I'm probably missing your point. What do you propose that Spatial4j should do/not-do?
2. dsmiley commented on Mar 13, 2022

   

   dsmiley

   on Mar 13, 2022

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   If you are proposing that the shape be eagerly validated (on construction) then that would definitely be a configurable option. I want to avoid re-validation of already validated data. Consider a persistent store of shapes that are retrieved and matched against some sort of query that needs to be real-time. The shapes were already validated when they were stored.
3. PapaStan commented on Mar 31, 2022

   

   PapaStan

   on Mar 31, 2022

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   My exemple is probably misleading.
   If we concentrate on the maybe failing part:

   import org.locationtech.spatial4j.context.jts.JtsSpatialContext;
   import org.locationtech.spatial4j.context.jts.JtsSpatialContextFactory;
   import org.locationtech.spatial4j.exception.InvalidShapeException;
   import org.locationtech.spatial4j.shape.jts.JtsShapeFactory;
   
   public class Main {
   
       public static void main(String[] args) throws Exception {
           JtsSpatialContextFactory ctxFactory = new JtsSpatialContextFactory();
           ctxFactory.geo = false;
           ctxFactory.useJtsLineString = true;
           ctxFactory.useJtsMulti = true;
           ctxFactory.useJtsPoint = true;
           JtsSpatialContext ctx = new JtsSpatialContext(ctxFactory);
           JtsShapeFactory shapeFactory = new JtsShapeFactory(ctx, ctxFactory);
   
           JtsShapeFactory.PolygonBuilder polygonBuilder = shapeFactory.polygon()
                   .pointLatLon(1, 1)
                   .pointLatLon(-1, -1)
                   .pointLatLon(1, -1)
                   .pointLatLon(-1, 1)
                   .pointLatLon(1, 1);
   
           try {
               shapeFactory.multiPolygon().add(polygonBuilder).build();
               System.out.println("OK");
           } catch (InvalidShapeException e) {
               System.out.println("KO: " + e.getMessage());
           }
       }
   
   }

   We get OK as output, meaning that the invalid polygon has been used in the creation of the multipolygon without failing.

   I expect the MultiPolygonBuilder to validate the polygon at some point.

   Digging a bit made me notice that the JtsShapeFactory$JtsMultiPolygonBuilder does not build polygons the same way the JtsShapeFactory$JtsPolygonBuilder does and may be the reason why the invalid polygons are created wihtout validation.

   Thank you for your time