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Java > Open Source Codes > org > netbeans > lib > lexer > test > simple > SimplePlainLexer


1 /*
2  * The contents of this file are subject to the terms of the Common Development
3  * and Distribution License (the License). You may not use this file except in
4  * compliance with the License.
5  *
6  * You can obtain a copy of the License at http://www.netbeans.org/cddl.html
7  * or http://www.netbeans.org/cddl.txt.
8  *
9  * When distributing Covered Code, include this CDDL Header Notice in each file
10  * and include the License file at http://www.netbeans.org/cddl.txt.
11  * If applicable, add the following below the CDDL Header, with the fields
12  * enclosed by brackets [] replaced by your own identifying information:
13  * "Portions Copyrighted [year] [name of copyright owner]"
14  *
15  * The Original Software is NetBeans. The Initial Developer of the Original
16  * Software is Sun Microsystems, Inc. Portions Copyright 1997-2007 Sun
17  * Microsystems, Inc. All Rights Reserved.
18  */
19
20 package org.netbeans.lib.lexer.test.simple;
21
22 import org.netbeans.api.lexer.Token;
23 import org.netbeans.spi.lexer.Lexer;
24 import org.netbeans.spi.lexer.LexerInput;
25 import org.netbeans.spi.lexer.LexerRestartInfo;
26 import org.netbeans.spi.lexer.TokenFactory;
27
28 /**
29  * Simple implementation a lexer.
30  *
31  * @author mmetelka
32  */
33 final class SimplePlainLexer implements Lexer<SimplePlainTokenId> {
34
35     // Copy of LexerInput.EOF
36 private static final int EOF = LexerInput.EOF;
37
38     private static final int INIT = 0;
39     private static final int IN_WORD = 1;
40     private static final int IN_WHITESPACE = 2;
41     
42     
43     private LexerInput input;
44     
45     private TokenFactory<SimplePlainTokenId> tokenFactory;
46     
47     private int state = INIT;
48     
49     SimplePlainLexer(LexerRestartInfo<SimplePlainTokenId> info) {
50         this.input = info.input();
51         this.tokenFactory = info.tokenFactory();
52         assert (info.state() == null);
53     }
54     
55     public Token<SimplePlainTokenId> nextToken() {
56         while (true) {
57             int ch = input.read();
58             switch (state) {
59                 case INIT:
60                     if (ch == EOF) {
61                         return null;
62                     } else if (Character.isWhitespace((char)ch)) { // start of whitespace
63 state = IN_WHITESPACE;
64                     } else { // start of word
65 state = IN_WORD;
66                     }
67                     break;
68
69                 case IN_WORD:
70                     while (true) {
71                         if (ch == EOF || Character.isWhitespace((char)ch)) {
72                             if (ch != EOF) { // no backup of EOF
73 input.backup(1);
74                             }
75                             state = INIT;
76                             return tokenFactory.createToken(SimplePlainTokenId.WORD);
77                         }
78                         ch = input.read();
79                     }
80                     // break;
81
82                 case IN_WHITESPACE:
83                     while (true) {
84                         if (ch == EOF || !Character.isWhitespace((char)ch)) {
85                             if (ch != EOF) { // no backup of EOF
86 input.backup(1);
87                             }
88                             state = INIT;
89                             return tokenFactory.createToken(SimplePlainTokenId.WHITESPACE);
90                         }
91                         ch = input.read();
92                     }
93                     // break;
94
95                 default:
96                     throw new IllegalStateException JavaDoc();
97             }
98         }
99     }
100     
101     public Object JavaDoc state() {
102         return null; // always in default state after token recognition
103 }
104     
105     public void release() {
106     }
107
108 }
109
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