code: public static FilterOperator toFilterOperator(ComparableFilter.Operator operator) {
  		if (operator == ComparableFilter.Operator.EQUAL_TO) {
  			return FilterOperator.EQUAL;
  		} else if (operator == ComparableFilter.Operator.GREATER_THAN) {
  			return FilterOperator.GREATER_THAN;
  		} else if (operator == ComparableFilter.Operator.GREATER_THAN_OR_EQUAL_TO) {
  			return FilterOperator.GREATER_THAN_OR_EQUAL;
  		} else if (operator == ComparableFilter.Operator.LESS_THAN) {
  			return FilterOperator.LESS_THAN;
  		} else if (operator == ComparableFilter.Operator.LESS_THAN_OR_EQUAL_TO) {
  			return FilterOperator.LESS_THAN_OR_EQUAL;
  		} else if (operator == ComparableFilter.Operator.NOT_EQUAL_TO) {
  			return FilterOperator.NOT_EQUAL;
  		} else {
  			throw new UnsupportedOperationException("Operator [" + operator
  					+ "] is not supported by Google App Engine Datastore");
  		}
  	}
docs: Translates {@code ComparableFilter.Operator} to Google App Engine
  Datastore {@code FilterOperator}.
  
  @param operator Acid House {@code ComparableFilter.Operator}.
  @return Google App Engine Datastore {@code FilterOperator} translated
  from Acid House {@code ComparableFilter.Operator}.