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package tim.prune.save;
import javax.swing.JButton;
import javax.swing.ListSelectionModel;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
/**
* Class to enable and disable a pair of up and down buttons
*/
public class UpDownToggler implements ListSelectionListener
{
private JButton _upButton = null;
private JButton _downButton = null;
private int _maxIndex = 2;
/**
* Constructor giving buttons to enable/disable
* @param inUpButton up button
* @param inDownButton down button
*/
public UpDownToggler(JButton inUpButton, JButton inDownButton)
{
_upButton = inUpButton;
_downButton = inDownButton;
}
/**
* Set the list size
* @param inListSize number of items in list
*/
public void setListSize(int inListSize)
{
_maxIndex = inListSize - 1;
}
/**
* list selection has changed
*/
public void valueChanged(ListSelectionEvent e)
{
ListSelectionModel lsm = (ListSelectionModel) e.getSource();
if (lsm.isSelectionEmpty())
{
// no rows are selected
_upButton.setEnabled(false);
_downButton.setEnabled(false);
}
else
{
// single row is selected
int row = lsm.getMinSelectionIndex();
_upButton.setEnabled(row > 0);
_downButton.setEnabled(row >= 0 && row < _maxIndex);
}
}
}
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