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Java > Open Source Codes > org > ungoverned > oscar > ldap > LdapLexer


1 /*
2  * Oscar - An implementation of the OSGi framework.
3  * Copyright (c) 2004, Richard S. Hall
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  *
10  * * Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
12  * * Redistributions in binary form must reproduce the above copyright
13  * notice, this list of conditions and the following disclaimer in
14  * the documentation and/or other materials provided with the
15  * distribution.
16  * * Neither the name of the ungoverned.org nor the names of its
17  * contributors may be used to endorse or promote products derived
18  * from this software without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  *
32  * Contact: Richard S. Hall (heavy@ungoverned.org)
33  * Contributor(s):
34  * Dennis Heimbigner
35  *
36 **/
37 package org.ungoverned.oscar.ldap;
38
39 import java.io.IOException JavaDoc;
40 import java.io.Reader JavaDoc;
41
42 public class LdapLexer {
43
44     static final int EOF = -1;
45     static final int NOCHAR = 0; // signal no peeked char; different from EOF
46
47     public static final String JavaDoc WHITESPACE = " \t\n\r";
48
49     Reader JavaDoc reader = null;
50
51     int nextChar = NOCHAR; // last peeked character
52
53     public LdapLexer() {}
54
55     public LdapLexer(Reader JavaDoc r)
56     {
57     setReader(r);
58     charno = 1;
59     }
60
61     public void setReader(Reader JavaDoc r)
62     {
63     reader = r;
64     }
65
66     /*
67     The procedures get(),peek(),skipwhitespace(),getnw(), and peeknw()
68     provide the essential LdapLexer interface.
69     */
70
71     public int get() throws IOException JavaDoc // any next char
72 {
73     if(nextChar == NOCHAR) return readChar();
74     int c = nextChar;
75     nextChar = NOCHAR;
76     return c;
77     }
78
79     public int peek() throws IOException JavaDoc
80     {
81     if(nextChar == NOCHAR) {
82         nextChar = readChar();
83     }
84     return nextChar;
85     }
86
87     void skipwhitespace() throws IOException JavaDoc
88     {
89     while(WHITESPACE.indexOf(peek()) >= 0) get();
90     }
91
92     public int getnw() throws IOException JavaDoc // next non-whitespace char
93 { // (note: not essential but useful)
94 skipwhitespace();
95     return get();
96     }
97
98     public int peeknw() throws IOException JavaDoc // next non-whitespace char
99 { // (note: not essential but useful)
100 skipwhitespace();
101     return peek();
102     }
103
104     // Following is for error reporting
105
106     // Pass all character reads thru this so we can track char count
107
108     int charno; // 1-based
109
110     public int charno() {return charno;}
111
112     int readChar() throws IOException JavaDoc
113     {
114     charno++;
115     return reader.read();
116     }
117
118 }
119
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