diff options
Diffstat (limited to 'qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java')
-rw-r--r-- | qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java b/qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java new file mode 100644 index 0000000000..8226cc77cb --- /dev/null +++ b/qpid/java/common/src/main/java/org/apache/qpid/messaging/util/Lexer.java @@ -0,0 +1,84 @@ +/* + * + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + * + */ +package org.apache.qpid.messaging.util; + +import java.util.ArrayList; +import java.util.Iterator; +import java.util.List; +import java.util.NoSuchElementException; +import java.util.regex.Matcher; +import java.util.regex.Pattern; + + +/** + * Lexer + * + */ + +public class Lexer +{ + + private List<Token.Type> types; + private Token.Type eof; + private Pattern rexp; + + public Lexer(List<Token.Type> types, Token.Type eof, Pattern rexp) + { + this.types = types; + this.eof = eof; + this.rexp = rexp; + } + + public List<Token> lex(final String st) + { + List<Token> tokens = new ArrayList<Token>(); + + int position = 0; + Matcher m = rexp.matcher(st); + OUTER: while (position < st.length()) + { + m.region(position, st.length()); + if (m.lookingAt()) + { + for (int i = 1; i <= m.groupCount(); i++) + { + String value = m.group(i); + if (value != null) + { + tokens.add(new Token(types.get(i-1), value, st, m.start(i))); + position = m.end(i); + continue OUTER; + } + } + throw new RuntimeException("no group matched"); + } + else + { + throw new LexError("unrecognized characters line:" + LineInfo.get(st, position)); + } + } + + tokens.add(new Token(eof, null, st, position)); + + return tokens; + } + +} |