Examples with ParserHelper org.drools.compiler.lang.ParserHelper used on opensource projects

Example 1 with ParserHelper

use of org.drools.compiler.lang.ParserHelper in project drools by kiegroup.

the class DrlExprParser method parse.

/**
 * Parse an expression from text
 */
public ConstraintConnectiveDescr parse(final String text) {
    ConstraintConnectiveDescr constraint = null;
    try {
        DRLLexer lexer = DRLFactory.getDRLLexer(new ANTLRStringStream(text), languageLevel);
        CommonTokenStream input = new CommonTokenStream(lexer);
        RecognizerSharedState state = new RecognizerSharedState();
        helper = new ParserHelper(input, state, languageLevel);
        DRLExpressions parser = DRLFactory.getDRLExpressions(input, state, helper, languageLevel);
        parser.setBuildDescr(true);
        // setting initial value just in case
        parser.setLeftMostExpr(null);
        BaseDescr expr = parser.conditionalOrExpression();
        if (expr != null && !parser.hasErrors()) {
            constraint = ConstraintConnectiveDescr.newAnd();
            constraint.addOrMerge(expr);
        }
    } catch (RecognitionException e) {
        helper.reportError(e);
    }
    return constraint;
}