    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    }