if ( patternDescr.getSource() != null ) {
// we have a pattern source, so build it
RuleConditionBuilder builder = (RuleConditionBuilder) context.getDialect().getBuilder( patternDescr.getSource().getClass() );
PatternSource source = (PatternSource) builder.build( context,
patternDescr.getSource() );
if ( source instanceof From ) {
((From) source).setResultPattern( pattern );
}
pattern.setSource( source );