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Java > Open Source Codes > jline > CursorBuffer


1 /**
2  * jline - Java console input library
3  * Copyright (c) 2002-2006, Marc Prud'hommeaux <mwp1@cornell.edu>
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or
7  * without modification, are permitted provided that the following
8  * conditions are met:
9  *
10  * Redistributions of source code must retain the above copyright
11  * notice, this list of conditions and the following disclaimer.
12  *
13  * Redistributions in binary form must reproduce the above copyright
14  * notice, this list of conditions and the following disclaimer
15  * in the documentation and/or other materials provided with
16  * the distribution.
17  *
18  * Neither the name of JLine nor the names of its contributors
19  * may be used to endorse or promote products derived from this
20  * software without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
24  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
25  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
26  * EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
28  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
29  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
31  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
33  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
34  * OF THE POSSIBILITY OF SUCH DAMAGE.
35  */
36 package jline;
37
38 /**
39  * A CursorBuffer is a holder for a {@link StringBuffer} that
40  * also contains the current cursor position.
41  *
42  * @author <a HREF="mailto:mwp1@cornell.edu">Marc Prud'hommeaux</a>
43  */
44 public class CursorBuffer
45 {
46     public int cursor = 0;
47     public final StringBuffer JavaDoc buffer = new StringBuffer JavaDoc ();
48
49
50     public int length ()
51     {
52         return buffer.length ();
53     }
54
55
56     public char current ()
57     {
58         if (cursor <= 0)
59             return 0;
60
61         return buffer.charAt (cursor - 1);
62     }
63
64
65     /**
66      * Insert the specific character into the buffer, setting the
67      * cursor position ahead one.
68      *
69      * @param c the character to insert
70      */
71     public void insert (final char c)
72     {
73         buffer.insert (cursor++, c);
74     }
75
76
77     /**
78      * Insert the specified {@link String} into the buffer, setting
79      * the cursor to the end of the insertion point.
80      *
81      * @param str the String to insert. Must not be null.
82      */
83     public void insert (final String JavaDoc str)
84     {
85         if (buffer.length () == 0)
86             buffer.append (str);
87         else
88             buffer.insert (cursor, str);
89
90         cursor += str.length ();
91     }
92
93
94     public String JavaDoc toString ()
95     {
96         return buffer.toString ();
97     }
98 }
99
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