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.matchers;
018
019import org.parboiled.MatcherContext;
020import org.parboiled.Rule;
021import org.parboiled.errors.GrammarException;
022import org.parboiled.matchervisitors.MatcherVisitor;
023
024import static org.parboiled.common.Preconditions.checkArgNotNull;
025
026/**
027 * A {@link Matcher} that repeatedly tries its submatcher against the input.
028 * Succeeds if its submatcher succeeds at least once.
029 */
030public class OneOrMoreMatcher extends CustomDefaultLabelMatcher<OneOrMoreMatcher> {
031    public final Matcher subMatcher;
032
033    public OneOrMoreMatcher(Rule subRule) {
034        super(checkArgNotNull(subRule, "subRule"), "OneOrMore");
035        this.subMatcher = getChildren().get(0);
036    }
037
038    public boolean match(MatcherContext context) {
039        boolean matched = subMatcher.getSubContext(context).runMatcher();
040        if (!matched) return false;
041
042        // collect all further matches as well
043        int lastIndex = context.getCurrentIndex();
044        while (subMatcher.getSubContext(context).runMatcher()) {
045            int currentIndex = context.getCurrentIndex();
046            if (currentIndex == lastIndex) {
047                throw new GrammarException("The inner rule of OneOrMore rule '%s' must not allow empty matches",
048                        context.getPath());
049            }
050            lastIndex = currentIndex;
051        }
052
053        context.createNode();
054        return true;
055    }
056
057    public <R> R accept(MatcherVisitor<R> visitor) {
058        checkArgNotNull(visitor, "visitor");
059        return visitor.visit(this);
060    }
061}