code: private static boolean polygonContainsPolygon_(Polygon polygon_a,
  			Polygon polygon_b, double tolerance,
  			ProgressTracker progress_tracker) {
  		Envelope2D env_a = new Envelope2D(), env_b = new Envelope2D();
  		polygon_a.queryEnvelope2D(env_a);
  		polygon_b.queryEnvelope2D(env_b);
  
  		// Quick envelope rejection test for false equality.
  		if (!envelopeInfContainsEnvelope_(env_a, env_b, tolerance))
  			return false;
  
  		// Quick rasterize test to see whether the the geometries are disjoint,
  		// or if one is contained in the other.
  		int relation = tryRasterizedContainsOrDisjoint_(polygon_a, polygon_b,
  				tolerance, false);
  
  		if (relation == Relation.disjoint || relation == Relation.within)
  			return false;
  
  		if (relation == Relation.contains)
  			return true;
  
  		return polygonContainsPolygonImpl_(polygon_a, polygon_b, tolerance,
  				progress_tracker);
  	}
docs: Returns true if polygon_a contains polygon_b.