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 package org.apache.directory.shared.ldap.schema.parsers; 021 022 import java.io.Reader; 023 024 import org.apache.directory.shared.ldap.schema.syntax.AntlrSchemaLexer; 025 026 import antlr.CharBuffer; 027 import antlr.LexerSharedInputState; 028 029 /** 030 * A reusable lexer class extended from antlr generated lexer for an LDAP 031 * schema as defined in RFC 4512. This class 032 * enables the reuse of the antlr lexer without having to recreate the it every 033 * time as stated in <a 034 * href="http://www.antlr.org:8080/pipermail/antlr-interest/2003-April/003631.html"> 035 * a Antlr Interest Group mail</a> . 036 * 037 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a> 038 * @version $Rev$, $Date$ 039 */ 040 public class ReusableAntlrSchemaLexer extends AntlrSchemaLexer 041 { 042 private boolean savedCaseSensitive; 043 044 private boolean savedCaseSensitiveLiterals; 045 046 047 /** 048 * Creates a ReusableAntlrSchemaLexer instance. 049 * 050 * @param in 051 * the input to the lexer 052 */ 053 public ReusableAntlrSchemaLexer( Reader in ) 054 { 055 super( in ); 056 savedCaseSensitive = getCaseSensitive(); 057 savedCaseSensitiveLiterals = getCaseSensitiveLiterals(); 058 } 059 060 061 /** 062 * Resets the state of an antlr lexer and initializes it with new input. 063 * 064 * @param in 065 * the input to the lexer 066 */ 067 public void prepareNextInput( Reader in ) 068 { 069 CharBuffer buf = new CharBuffer( in ); 070 LexerSharedInputState state = new LexerSharedInputState( buf ); 071 this.setInputState( state ); 072 073 this.setCaseSensitive( savedCaseSensitive ); 074 075 // no set method for this protected field. 076 this.caseSensitiveLiterals = savedCaseSensitiveLiterals; 077 } 078 }