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Java > Open Source Codes > org > jfree > ui > LengthLimitingDocument


1 /* ========================================================================
2  * JCommon : a free general purpose class library for the Java(tm) platform
3  * ========================================================================
4  *
5  * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
6  *
7  * Project Info: http://www.jfree.org/jcommon/index.html
8  *
9  * This library is free software; you can redistribute it and/or modify it
10  * under the terms of the GNU Lesser General Public License as published by
11  * the Free Software Foundation; either version 2.1 of the License, or
12  * (at your option) any later version.
13  *
14  * This library is distributed in the hope that it will be useful, but
15  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16  * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17  * License for more details.
18  *
19  * You should have received a copy of the GNU Lesser General Public
20  * License along with this library; if not, write to the Free Software
21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22  * USA.
23  *
24  * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25  * in the United States and other countries.]
26  *
27  * ---------------------------
28  * LengthLimitingDocument.java
29  * ---------------------------
30  * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
31  *
32  * Original Author: Thomas Morgner;
33  * Contributor(s): David Gilbert (for Object Refinery Limited);
34  *
35  * $Id: LengthLimitingDocument.java,v 1.3 2005/10/18 13:18:34 mungady Exp $
36  *
37  * Changes
38  * -------
39  * 22-Jan-2003 : Initial version
40  * 05-Feb-2003 : Documentation
41  *
42  */
43
44 package org.jfree.ui;
45
46 import javax.swing.text.AttributeSet JavaDoc;
47 import javax.swing.text.BadLocationException JavaDoc;
48 import javax.swing.text.PlainDocument JavaDoc;
49
50 /**
51  * This Document restricts the size of the contained plain text to the given number of
52  * characters.
53  *
54  * @author Thomas Morgner
55  */
56 public class LengthLimitingDocument extends PlainDocument JavaDoc {
57
58     /** The maximum length. */
59     private int maxlen;
60
61     /**
62      * Creates a new LengthLimitingDocument, with no limitation.
63      */
64     public LengthLimitingDocument() {
65         this(-1);
66     }
67
68     /**
69      * Creates a new LengthLimitingDocument with the given limitation. No more than
70      * maxlen characters can be added to the document. If maxlen is negative, then
71      * no length check is performed.
72      *
73      * @param maxlen the maximum number of elements in this document
74      */
75     public LengthLimitingDocument(final int maxlen) {
76         super();
77         this.maxlen = maxlen;
78     }
79
80     /**
81      * Sets the maximum number of characters for this document. Existing characters
82      * are not removed.
83      *
84      * @param maxlen the maximum number of characters in this document.
85      */
86     public void setMaxLength(final int maxlen) {
87         this.maxlen = maxlen;
88     }
89
90     /**
91      * Returns the defined maximum number characters for this document.
92      * @return the maximum number of characters
93      */
94     public int getMaxLength() {
95         return this.maxlen;
96     }
97
98     /**
99      * Inserts the string into the document. If the length of the document would
100      * violate the maximum characters restriction, then the string is cut down so
101      * that
102      * @param offs the offset, where the string should be inserted into the document
103      * @param str the string that should be inserted
104      * @param a the attribute set assigned for the document
105      * @throws javax.swing.text.BadLocationException if the offset is not correct
106      */
107     public void insertString(final int offs, final String JavaDoc str, final AttributeSet JavaDoc a)
108         throws BadLocationException JavaDoc {
109         if (str == null) {
110             return;
111         }
112
113         if (this.maxlen < 0) {
114             super.insertString(offs, str, a);
115         }
116
117         final char[] numeric = str.toCharArray();
118         final StringBuffer JavaDoc b = new StringBuffer JavaDoc();
119         b.append(numeric, 0, Math.min(this.maxlen, numeric.length));
120         super.insertString(offs, b.toString(), a);
121     }
122     
123 }
124
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