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.AntlrSubtreeSpecificationLexer; 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 ReusableAntlrSubtreeSpecificationLexer extends AntlrSubtreeSpecificationLexer 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 ReusableAntlrSubtreeSpecificationLexer(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 }