// EXISTS must save some context info to restore it later
final int currentPatternIndex = context.getCurrentPatternOffset();
final LeftTupleSource tupleSource = context.getTupleSource();
// get child
final RuleConditionElement child = (RuleConditionElement) exists.getChildren().get( 0 );
// get builder for child
final ReteooComponentBuilder builder = utils.getBuilderFor( child );
// builds the child