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package org.openslx.dozmod.gui.control;
import java.awt.Component;
import java.util.Comparator;
import javax.swing.ComboBoxModel;
import javax.swing.DefaultListCellRenderer;
import javax.swing.JComboBox;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.ListCellRenderer;
@SuppressWarnings("serial")
public class ComboBox<T> extends JComboBox<T> {
public static abstract class ComboBoxRenderer<T> {
public abstract String renderItem(T item);
public String getEmptyText() {
return null;
}
}
private final Comparator<T> equalityComparator;
private final ComboBoxRenderer<T> itemRenderer;
private final ComboBox<T> me = this;
private boolean replacedRenderer = false;
public ComboBox(ComboBoxRenderer<T> renderer) {
this(null, renderer);
}
public ComboBox(Comparator<T> equalityComparator, ComboBoxRenderer<T> renderer) {
super();
this.itemRenderer = renderer;
this.equalityComparator = equalityComparator;
}
/**
* This version of {@link JComboBox#setSelectedItem(Object)} will use the
* comparator given when constructing the ComboBox to determine if an entry
* should be selected.
*/
@SuppressWarnings("unchecked")
@Override
public void setSelectedItem(Object anObject) {
if (anObject != null && equalityComparator != null) {
ComboBoxModel<T> model = getModel();
try {
for (int i = 0; i < model.getSize(); ++i) {
T element = model.getElementAt(i);
if (equalityComparator.compare((T) anObject, element) == 0) {
anObject = element;
break;
}
}
} catch (ClassCastException e) {
// Bummer, fall through
}
}
super.setSelectedItem(anObject);
}
@Override
public void updateUI() {
super.updateUI();
if (!replacedRenderer) {
replacedRenderer = true;
final ListCellRenderer<? super T> oldRenderer = super.getRenderer();
if (oldRenderer instanceof JLabel) {
// The default JComboBox renderer always seems to be a subclass of JLabel, which is nice
super.setRenderer(new ListCellRenderer<T>() {
@Override
public Component getListCellRendererComponent(JList<? extends T> list, T value,
int index, boolean isSelected, boolean cellHasFocus) {
String text;
if (me.getModel().getSize() == 0) {
text = itemRenderer.getEmptyText();
} else {
text = itemRenderer.renderItem(value);
}
Component comp = oldRenderer.getListCellRendererComponent(list, null, index,
isSelected, cellHasFocus);
comp.setEnabled(me.isEnabled());
((JLabel) comp).setText(text);
return comp;
}
});
} else {
// Fallback, in case there's any platform, L&F, runtime environment or whatnot where it's not a JLabel
super.setRenderer(new DefaultListCellRenderer() {
@SuppressWarnings("unchecked")
@Override
public Component getListCellRendererComponent(JList<?> list, Object value, int index,
boolean isSelected, boolean cellHasFocus) {
if (me.getModel().getSize() == 0) {
value = itemRenderer.getEmptyText();
} else {
try {
value = itemRenderer.renderItem((T) value);
} catch (ClassCastException e) {
// Should never happen; do nothing, retain original value
}
}
return super.getListCellRendererComponent(list, value, index, isSelected,
cellHasFocus);
}
});
}
}
}
}
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