1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20
21 package org.apache.directory.api.ldap.trigger;
22
23
24 import java.io.Reader;
25
26 import antlr.CharBuffer;
27 import antlr.LexerSharedInputState;
28
29
30 /**
31 * A reusable lexer class extended from antlr generated lexer for an LDAP
32 * Trigger Specification as defined at <a
33 * href="http://docs.safehaus.org/display/APACHEDS/Grammar+for+Triggers">
34 * The ABNF grammar for LDAP Triggers</a>.
35 *
36 * <p>This class enables the reuse of the antlr lexer without having to recreate
37 * the it every time as stated in <a
38 * href="http://www.antlr.org:8080/pipermail/antlr-interest/2003-April/003631.html">
39 * an ANTLR Interest Group mail</a> .
40 *
41 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
42 */
43 class ReusableAntlrTriggerSpecificationLexer extends AntlrTriggerSpecificationLexer
44 {
45 private boolean savedCaseSensitive;
46
47 private boolean savedCaseSensitiveLiterals;
48
49
50 /**
51 * Creates a ReusableAntlrTriggerSpecificationLexer instance.
52 *
53 * @param in
54 * the input to the lexer
55 */
56 public ReusableAntlrTriggerSpecificationLexer( Reader in )
57 {
58 super( in );
59 savedCaseSensitive = getCaseSensitive();
60 savedCaseSensitiveLiterals = getCaseSensitiveLiterals();
61 }
62
63
64 /**
65 * Resets the state of an antlr lexer and initializes it with new input.
66 *
67 * @param in
68 * the input to the lexer
69 */
70 public void prepareNextInput( Reader in )
71 {
72 CharBuffer buf = new CharBuffer( in );
73 LexerSharedInputState state = new LexerSharedInputState( buf );
74 this.setInputState( state );
75
76 this.setCaseSensitive( savedCaseSensitive );
77
78 // no set method for this protected field
79 this.caseSensitiveLiterals = savedCaseSensitiveLiterals;
80 }
81 }