001/*-------------------------------------------------------------------------+
002|                                                                          |
003| Copyright 2005-2011 the ConQAT Project                                   |
004|                                                                          |
005| Licensed under the Apache License, Version 2.0 (the "License");          |
006| you may not use this file except in compliance with the License.         |
007| You may obtain a copy of the License at                                  |
008|                                                                          |
009|    http://www.apache.org/licenses/LICENSE-2.0                            |
010|                                                                          |
011| Unless required by applicable law or agreed to in writing, software      |
012| distributed under the License is distributed on an "AS IS" BASIS,        |
013| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
014| See the License for the specific language governing permissions and      |
015| limitations under the License.                                           |
016+-------------------------------------------------------------------------*/
017package eu.cqse.check.framework.util.tokens;
018
019import java.util.Arrays;
020
021/**
022 * Matches if any of the given sub patterns matches.
023 */
024public class AlternativePattern extends TokenPatternBase {
025
026        /** The subpatterns that are tried in order. */
027        private final TokenPatternBase[] matchers;
028
029        /** Constructor. */
030        public AlternativePattern(TokenPatternBase[] matchers) {
031                this.matchers = matchers;
032        }
033
034        /** {@inheritDoc} */
035        @Override
036        protected TokenPatternMatch matchesLocally(TokenStream stream) {
037                int beforeAlternative = stream.getPosition();
038                for (TokenPatternBase matcher : matchers) {
039                        TokenPatternMatch match = matcher.matches(stream);
040                        if (match != null) {
041                                return match;
042                        }
043                        stream.setPosition(beforeAlternative);
044                }
045                return null;
046        }
047
048        /** {@inheritDoc} */
049        @Override
050        public String toString() {
051                return "Alternative " + Arrays.toString(matchers);
052        }
053
054}