package org.jtheque.utils.ui;

 /*

  * This file is part of JTheque.

  *

  * JTheque is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, either version 3 of the License.

  *

  * JTheque is distributed in the hope that it will be useful,

  * but WITHOUT ANY WARRANTY; without even the implied warranty of

  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

  * GNU General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with JTheque.  If not, see <http://www.gnu.org/licenses/>.

  */

 import javax.swing.text.AttributeSet;

 import javax.swing.text.BadLocationException;

 import javax.swing.text.DocumentFilter;

 import java.awt.Toolkit;

 /**

  * A document filter used to limit the length of a field.

  *

  * @author Baptiste Wicht

  */

 public class DocumentLengthFilter extends DocumentFilter {

     private final int max;

     private static final int DEFAULT_LENGTH_LIMIT = 50;

     /**

      * Construct a new <code>DocumentLengthFilter</code> with a default maximum number of characters. By default,

      * only 50 characters are accepted.

      */

     public DocumentLengthFilter() {

         this(DEFAULT_LENGTH_LIMIT);

     }

     /**

      * Construct a new <code>DocumentLengthFilter</code> with a maximum number of characters.

      *

      * @param max The maximum number of characters permitted in the document.

      */

     public DocumentLengthFilter(int max) {

         super();

         this.max = max;

     }

     @Override

     public final void insertString(DocumentFilter.FilterBypass fb, int offset, String str,

                                    AttributeSet attrs) throws BadLocationException {

         replace(fb, offset, 0, str, attrs);

     }

     @Override

     public void replace(DocumentFilter.FilterBypass fb, int offset, int length, String str,

                         AttributeSet attrs) throws BadLocationException {

         int newLength = fb.getDocument().getLength() - length + str.length();

         if (newLength <= max) {

             fb.replace(offset, length, str, attrs);

         } else {

             Toolkit.getDefaultToolkit().beep();

         }

     }

     /**

      * Return the maximum number of characters permitted in the document.

      *

      * @return The number.

      */

     protected final int getMax() {

         return max;

     }

 }