001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License. You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied. See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 *
019 */
020
021 package org.apache.directory.shared.ldap.subtree;
022
023
024 import java.io.Reader;
025
026 import org.apache.directory.shared.ldap.subtree.AntlrSubtreeSpecificationCheckerLexer;
027
028 import antlr.CharBuffer;
029 import antlr.LexerSharedInputState;
030
031
032 /**
033 * A reusable lexer class extended from antlr generated lexer for an LDAP
034 * subtree specification as defined by <a
035 * href="http://www.faqs.org/rfcs/rfc3672.html"> RFC 3672</a>. This class
036 * enables the reuse of the antlr lexer without having to recreate the it every
037 * time as stated in <a
038 * href="http://www.antlr.org:8080/pipermail/antlr-interest/2003-April/003631.html">
039 * a Antlr Interest Group mail</a> .
040 *
041 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a>
042 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
043 * @version $Rev: 437007 $
044 */
045 public class ReusableAntlrSubtreeSpecificationCheckerLexer extends AntlrSubtreeSpecificationCheckerLexer
046 {
047 private boolean savedCaseSensitive;
048
049 private boolean savedCaseSensitiveLiterals;
050
051
052 /**
053 * Creates a ReusableAntlrSubtreeSpecificationLexer instance.
054 *
055 * @param in
056 * the input to the lexer
057 */
058 public ReusableAntlrSubtreeSpecificationCheckerLexer(Reader in)
059 {
060 super( in );
061 savedCaseSensitive = getCaseSensitive();
062 savedCaseSensitiveLiterals = getCaseSensitiveLiterals();
063 }
064
065
066 /**
067 * Resets the state of an antlr lexer and initializes it with new input.
068 *
069 * @param in
070 * the input to the lexer
071 */
072 public void prepareNextInput( Reader in )
073 {
074 CharBuffer buf = new CharBuffer( in );
075 LexerSharedInputState state = new LexerSharedInputState( buf );
076 this.setInputState( state );
077
078 this.setCaseSensitive( savedCaseSensitive );
079
080 // no set method for this protected field.
081 this.caseSensitiveLiterals = savedCaseSensitiveLiterals;
082 }
083 }