001/*
002 * Copyright (C) 2009-2011 Mathias Doenitz
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.parboiled.support;
018
019import org.parboiled.Node;
020import org.parboiled.common.Predicate;
021import org.parboiled.common.StringUtils;
022
023/**
024 * A simple Node predicate determining whether a Node matches a given label prefix.
025 * Useful for example for various methods of the {@link ParseTreeUtils}.
026 *
027 * @param <V> the type of the value field of a parse tree node
028 */
029public class LabelPrefixPredicate<V> implements Predicate<Node<V>> {
030    private final String labelPrefix;
031
032    public LabelPrefixPredicate(String labelPrefix) {
033        this.labelPrefix = labelPrefix;
034    }
035
036    public boolean apply(Node<V> input) {
037        return input != null && StringUtils.startsWith(input.getLabel(), labelPrefix);
038    }
039}