code: private static JsonStructure toJson( ITestCaseGenerator generator)
      {
      JsonObjectBuilder builder = Json.createObjectBuilder();
  
      if( generator.getClass().equals( TupleGenerator.class))
        {
        TupleGenerator tupleGenerator = (TupleGenerator) generator;
        builder.add( TUPLES_KEY, tupleGenerator.getDefaultTupleSize());
        Optional.ofNullable( tupleGenerator.getRandomSeed()).ifPresent( seed -> builder.add( SEED_KEY, seed));
        
        JsonArrayBuilder combinersBuilder = Json.createArrayBuilder();
        tupleGenerator.getCombiners().stream().forEach( combiner -> combinersBuilder.add( toJson( combiner)));
        JsonArray combiners = combinersBuilder.build();
        if( !combiners.isEmpty())
          {
          builder.add( COMBINERS_KEY, combiners);
          }
        }
  
      return builder.build();
      }
docs: Returns the JSON object that represents the given generator.