/*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
* JListHelper.java
* Copyright (C) 2005 University of Waikato, Hamilton, New Zealand
*
*/
package weka.gui;
import javax.swing.DefaultListModel;
import javax.swing.JList;
/**
* A helper class for JList GUI elements with DefaultListModel or
* derived models.
*
* @author FracPete (fracpete at waikato dot ac dot nz)
* @version $Revision: 1.1 $
* @see JList
* @see DefaultListModel
*/
public class JListHelper {
/** moves items up */
public final static int MOVE_UP = 0;
/** moves items down */
public final static int MOVE_DOWN = 1;
/**
* moves the selected items by a certain amount of items in a given direction
*
* @param list the JList to work on
* @param moveby the number of items to move by
* @param direction the direction to move in
* @see #MOVE_UP
* @see #MOVE_DOWN
*/
protected static void moveItems(JList list, int moveby, int direction) {
int[] indices;
int i;
Object o;
DefaultListModel model;
model = (DefaultListModel) list.getModel();
switch (direction) {
case MOVE_UP:
indices = list.getSelectedIndices();
for (i = 0; i < indices.length; i++) {
if (indices[i] == 0)
continue;
o = model.remove(indices[i]);
indices[i] -= moveby;
model.insertElementAt(o, indices[i]);
}
list.setSelectedIndices(indices);
break;
case MOVE_DOWN:
indices = list.getSelectedIndices();
for (i = indices.length - 1; i >= 0; i--) {
if (indices[i] == model.getSize() - 1)
continue;
o = model.remove(indices[i]);
indices[i] += moveby;
model.insertElementAt(o, indices[i]);
}
list.setSelectedIndices(indices);
break;
default:
System.err.println(
JListHelper.class.getName() + ": direction '"
+ direction + "' is unknown!");
}
}
/**
* moves the selected items up by 1
*
* @param list the JList to work on
*/
public static void moveUp(JList list) {
if (canMoveUp(list))
moveItems(list, 1, MOVE_UP);
}
/**
* moves the selected item down by 1
*
* @param list the JList to work on
*/
public static void moveDown(JList list) {
if (canMoveDown(list))
moveItems(list, 1, MOVE_DOWN);
}
/**
* moves the selected items to the top
*
* @param list the JList to work on
*/
public static void moveTop(JList list) {
int[] indices;
int diff;
if (canMoveUp(list)) {
indices = list.getSelectedIndices();
diff = indices[0];
moveItems(list, diff, MOVE_UP);
}
}
/**
* moves the selected items to the end
*
* @param list the JList to work on
*/
public static void moveBottom(JList list) {
int[] indices;
int diff;
if (canMoveDown(list)) {
indices = list.getSelectedIndices();
diff = list.getModel().getSize() - 1 - indices[indices.length - 1];
moveItems(list, diff, MOVE_DOWN);
}
}
/**
* checks whether the selected items can be moved up
*
* @param list the JList to work on
*/
public static boolean canMoveUp(JList list) {
boolean result;
int[] indices;
result = false;
indices = list.getSelectedIndices();
if (indices.length > 0) {
if (indices[0] > 0)
result = true;
}
return result;
}
/**
* checks whether the selected items can be moved down
*
* @param list the JList to work on
*/
public static boolean canMoveDown(JList list) {
boolean result;
int[] indices;
result = false;
indices = list.getSelectedIndices();
if (indices.length > 0) {
if (indices[indices.length - 1] < list.getModel().getSize() - 1)
result = true;
}
return result;
}
}