001 /* ========================================================================
002 * JCommon : a free general purpose class library for the Java(tm) platform
003 * ========================================================================
004 *
005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jcommon/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * ---------------------------
028 * LengthLimitingDocument.java
029 * ---------------------------
030 * (C)opyright 2003, 2004, by Thomas Morgner and Contributors.
031 *
032 * Original Author: Thomas Morgner;
033 * Contributor(s): David Gilbert (for Object Refinery Limited);
034 *
035 * $Id: LengthLimitingDocument.java,v 1.3 2005/10/18 13:18:34 mungady Exp $
036 *
037 * Changes
038 * -------
039 * 22-Jan-2003 : Initial version
040 * 05-Feb-2003 : Documentation
041 *
042 */
043
044 package org.jfree.ui;
045
046 import javax.swing.text.AttributeSet;
047 import javax.swing.text.BadLocationException;
048 import javax.swing.text.PlainDocument;
049
050 /**
051 * This Document restricts the size of the contained plain text to the given number of
052 * characters.
053 *
054 * @author Thomas Morgner
055 */
056 public class LengthLimitingDocument extends PlainDocument {
057
058 /** The maximum length. */
059 private int maxlen;
060
061 /**
062 * Creates a new LengthLimitingDocument, with no limitation.
063 */
064 public LengthLimitingDocument() {
065 this(-1);
066 }
067
068 /**
069 * Creates a new LengthLimitingDocument with the given limitation. No more than
070 * maxlen characters can be added to the document. If maxlen is negative, then
071 * no length check is performed.
072 *
073 * @param maxlen the maximum number of elements in this document
074 */
075 public LengthLimitingDocument(final int maxlen) {
076 super();
077 this.maxlen = maxlen;
078 }
079
080 /**
081 * Sets the maximum number of characters for this document. Existing characters
082 * are not removed.
083 *
084 * @param maxlen the maximum number of characters in this document.
085 */
086 public void setMaxLength(final int maxlen) {
087 this.maxlen = maxlen;
088 }
089
090 /**
091 * Returns the defined maximum number characters for this document.
092 * @return the maximum number of characters
093 */
094 public int getMaxLength() {
095 return this.maxlen;
096 }
097
098 /**
099 * 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 str, final AttributeSet a)
108 throws BadLocationException {
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 b = new StringBuffer();
119 b.append(numeric, 0, Math.min(this.maxlen, numeric.length));
120 super.insertString(offs, b.toString(), a);
121 }
122
123 }