Examples with AttributeExpressionParser org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser used on opensource projects

Example 1 with AttributeExpressionParser

use of org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser in project nifi by apache.

the class ExpressionCompiler method compileTree.

private Tree compileTree(final String expression) throws AttributeExpressionLanguageParsingException {
    try {
        final CharStream input = new ANTLRStringStream(expression);
        final AttributeExpressionLexer lexer = new AttributeExpressionLexer(input);
        final CommonTokenStream lexerTokenStream = new CommonTokenStream(lexer);
        final AttributeExpressionParser parser = new AttributeExpressionParser(lexerTokenStream);
        final Tree ast = (Tree) parser.query().getTree();
        final Tree tree = ast.getChild(0);
        // ensure that we are able to build the evaluators, so that we validate syntax
        final Evaluator<?> evaluator = buildEvaluator(tree);
        verifyMappingEvaluatorReduced(evaluator);
        return tree;
    } catch (final AttributeExpressionLanguageParsingException e) {
        throw e;
    } catch (final Exception e) {
        throw new AttributeExpressionLanguageParsingException(e);
    }
}

Example 2 with AttributeExpressionParser

use of org.apache.nifi.attribute.expression.language.antlr.AttributeExpressionParser in project nifi by apache.

the class ExpressionCompiler method compile.

public CompiledExpression compile(final String expression) {
    try {
        final CharStream input = new ANTLRStringStream(expression);
        final AttributeExpressionLexer lexer = new AttributeExpressionLexer(input);
        final CommonTokenStream lexerTokenStream = new CommonTokenStream(lexer);
        final AttributeExpressionParser parser = new AttributeExpressionParser(lexerTokenStream);
        final Tree ast = (Tree) parser.query().getTree();
        final Tree tree = ast.getChild(0);
        final Evaluator<?> evaluator = buildEvaluator(tree);
        verifyMappingEvaluatorReduced(evaluator);
        final Set<Evaluator<?>> allEvaluators = new HashSet<>(evaluators);
        this.evaluators.clear();
        return new CompiledExpression(expression, evaluator, tree, allEvaluators);
    } catch (final AttributeExpressionLanguageParsingException e) {
        throw e;
    } catch (final Exception e) {
        throw new AttributeExpressionLanguageParsingException(e);
    }
}