The KeyedComboBox model allows to define an internal key (the data element) for every entry in the model.
/*
* JCommon : a free general purpose class library for the Java(tm) platform
*
*
* (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
*
* Project Info: http://www.jfree.org/jcommon/index.html
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
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* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
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*
* [Java is a trademark or registered trademark of Sun Microsystems, Inc.
* in the United States and other countries.]
*
* ------------------
* KeyedComboBoxModel.java
* ------------------
* (C) Copyright 2004, by Thomas Morgner and Contributors.
*
* Original Author: Thomas Morgner;
* Contributor(s): David Gilbert (for Object Refinery Limited);
*
* $Id: KeyedComboBoxModel.java,v 1.8 2008/09/10 09:26:11 mungady Exp $
*
* Changes
* -------
* 07-Jun-2004 : Added JCommon header (DG);
*
*/
import java.util.ArrayList;
import javax.swing.ComboBoxModel;
import javax.swing.event.ListDataEvent;
import javax.swing.event.ListDataListener;
/**
* The KeyedComboBox model allows to define an internal key (the data element)
* for every entry in the model. <p/> This class is usefull in all cases, where
* the public text differs from the internal view on the data. A separation
* between presentation data and processing data is a prequesite for localizing
* combobox entries. This model does not allow selected elements, which are not
* in the list of valid elements.
*
* @author Thomas Morgner
*/
public class KeyedComboBoxModel implements ComboBoxModel {
/**
* The internal data carrier to map keys to values and vice versa.
*/
private static class ComboBoxItemPair {
/**
* The key.
*/
private Object key;
/**
* The value for the key.
*/
private Object value;
/**
* Creates a new item pair for the given key and value. The value can be
* changed later, if needed.
*
* @param key
* the key
* @param value
* the value
*/
public ComboBoxItemPair(final Object key, final Object value) {
this.key = key;
this.value = value;
}
/**
* Returns the key.
*
* @return the key.
*/
public Object getKey() {
return this.key;
}
/**
* Returns the value.
*
* @return the value for this key.
*/
public Object getValue() {
return this.value;
}
/**
* Redefines the value stored for that key.
*
* @param value
* the new value.
*/
public void setValue(final Object value) {
this.value = value;
}
}
/**
* The index of the selected item.
*/
private int selectedItemIndex;
private Object selectedItemValue;
/**
* The data (contains ComboBoxItemPairs).
*/
private ArrayList data;
/**
* The listeners.
*/
private ArrayList listdatalistener;
/**
* The cached listeners as array.
*/
private transient ListDataListener[] tempListeners;
private boolean allowOtherValue;
/**
* Creates a new keyed combobox model.
*/
public KeyedComboBoxModel() {
this.data = new ArrayList();
this.listdatalistener = new ArrayList();
}
/**
* Creates a new keyed combobox model for the given keys and values. Keys and
* values must have the same number of items.
*
* @param keys
* the keys
* @param values
* the values
*/
public KeyedComboBoxModel(final Object[] keys, final Object[] values) {
this();
setData(keys, values);
}
/**
* Replaces the data in this combobox model. The number of keys must be equals
* to the number of values.
*
* @param keys
* the keys
* @param values
* the values
*/
public void setData(final Object[] keys, final Object[] values) {
if (values.length != keys.length) {
throw new IllegalArgumentException("Values and text must have the same length.");
}
this.data.clear();
this.data.ensureCapacity(keys.length);
for (int i = 0; i < values.length; i++) {
add(keys[i], values[i]);
}
this.selectedItemIndex = -1;
final ListDataEvent evt = new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, 0, this.data
.size() - 1);
fireListDataEvent(evt);
}
/**
* Notifies all registered list data listener of the given event.
*
* @param evt
* the event.
*/
protected synchronized void fireListDataEvent(final ListDataEvent evt) {
if (this.tempListeners == null) {
this.tempListeners = (ListDataListener[]) this.listdatalistener
.toArray(new ListDataListener[this.listdatalistener.size()]);
}
final ListDataListener[] listeners = this.tempListeners;
for (int i = 0; i < listeners.length; i++) {
final ListDataListener l = listeners[i];
l.contentsChanged(evt);
}
}
/**
* Returns the selected item.
*
* @return The selected item or <code>null</code> if there is no selection
*/
public Object getSelectedItem() {
return this.selectedItemValue;
}
/**
* Defines the selected key. If the object is not in the list of values, no
* item gets selected.
*
* @param anItem
* the new selected item.
*/
public void setSelectedKey(final Object anItem) {
if (anItem == null) {
this.selectedItemIndex = -1;
this.selectedItemValue = null;
} else {
final int newSelectedItem = findDataElementIndex(anItem);
if (newSelectedItem == -1) {
this.selectedItemIndex = -1;
this.selectedItemValue = null;
} else {
this.selectedItemIndex = newSelectedItem;
this.selectedItemValue = getElementAt(this.selectedItemIndex);
}
}
fireListDataEvent(new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, -1, -1));
}
/**
* Set the selected item. The implementation of this method should notify all
* registered <code>ListDataListener</code>s that the contents have
* changed.
*
* @param anItem
* the list object to select or <code>null</code> to clear the
* selection
*/
public void setSelectedItem(final Object anItem) {
if (anItem == null) {
this.selectedItemIndex = -1;
this.selectedItemValue = null;
} else {
final int newSelectedItem = findElementIndex(anItem);
if (newSelectedItem == -1) {
if (isAllowOtherValue()) {
this.selectedItemIndex = -1;
this.selectedItemValue = anItem;
} else {
this.selectedItemIndex = -1;
this.selectedItemValue = null;
}
} else {
this.selectedItemIndex = newSelectedItem;
this.selectedItemValue = getElementAt(this.selectedItemIndex);
}
}
fireListDataEvent(new ListDataEvent(this, ListDataEvent.CONTENTS_CHANGED, -1, -1));
}
private boolean isAllowOtherValue() {
return this.allowOtherValue;
}
/**
* @param allowOtherValue
*/
public void setAllowOtherValue(final boolean allowOtherValue) {
this.allowOtherValue = allowOtherValue;
}
/**
* Adds a listener to the list that's notified each time a change to the data
* model occurs.
*
* @param l
* the <code>ListDataListener</code> to be added
*/
public synchronized void addListDataListener(final ListDataListener l) {
if (l == null) {
throw new NullPointerException();
}
this.listdatalistener.add(l);
this.tempListeners = null;
}
/**
* Returns the value at the specified index.
*
* @param index
* the requested index
* @return the value at <code>index</code>
*/
public Object getElementAt(final int index) {
if (index >= this.data.size()) {
return null;
}
final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(index);
if (datacon == null) {
return null;
}
return datacon.getValue();
}
/**
* Returns the key from the given index.
*
* @param index
* the index of the key.
* @return the the key at the specified index.
*/
public Object getKeyAt(final int index) {
if (index >= this.data.size()) {
return null;
}
if (index < 0) {
return null;
}
final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(index);
if (datacon == null) {
return null;
}
return datacon.getKey();
}
/**
* Returns the selected data element or null if none is set.
*
* @return the selected data element.
*/
public Object getSelectedKey() {
return getKeyAt(this.selectedItemIndex);
}
/**
* Returns the length of the list.
*
* @return the length of the list
*/
public int getSize() {
return this.data.size();
}
/**
* Removes a listener from the list that's notified each time a change to the
* data model occurs.
*
* @param l
* the <code>ListDataListener</code> to be removed
*/
public void removeListDataListener(final ListDataListener l) {
this.listdatalistener.remove(l);
this.tempListeners = null;
}
/**
* Searches an element by its data value. This method is called by the
* setSelectedItem method and returns the first occurence of the element.
*
* @param anItem
* the item
* @return the index of the item or -1 if not found.
*/
private int findDataElementIndex(final Object anItem) {
if (anItem == null) {
throw new NullPointerException("Item to find must not be null");
}
for (int i = 0; i < this.data.size(); i++) {
final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(i);
if (anItem.equals(datacon.getKey())) {
return i;
}
}
return -1;
}
/**
* Tries to find the index of element with the given key. The key must not be
* null.
*
* @param key
* the key for the element to be searched.
* @return the index of the key, or -1 if not found.
*/
public int findElementIndex(final Object key) {
if (key == null) {
throw new NullPointerException("Item to find must not be null");
}
for (int i = 0; i < this.data.size(); i++) {
final ComboBoxItemPair datacon = (ComboBoxItemPair) this.data.get(i);
if (key.equals(datacon.getValue())) {
return i;
}
}
return -1;
}
/**
* Removes an entry from the model.
*
* @param key
* the key
*/
public void removeDataElement(final Object key) {
final int idx = findDataElementIndex(key);
if (idx == -1) {
return;
}
this.data.remove(idx);
final ListDataEvent evt = new ListDataEvent(this, ListDataEvent.INTERVAL_REMOVED, idx, idx);
fireListDataEvent(evt);
}
/**
* Adds a new entry to the model.
*
* @param key
* the key
* @param cbitem
* the display value.
*/
public void add(final Object key, final Object cbitem) {
final ComboBoxItemPair con = new ComboBoxItemPair(key, cbitem);
this.data.add(con);
final ListDataEvent evt = new ListDataEvent(this, ListDataEvent.INTERVAL_ADDED, this.data
.size() - 2, this.data.size() - 2);
fireListDataEvent(evt);
}
/**
* Removes all entries from the model.
*/
public void clear() {
final int size = getSize();
this.data.clear();
final ListDataEvent evt = new ListDataEvent(this, ListDataEvent.INTERVAL_REMOVED, 0, size - 1);
fireListDataEvent(evt);
}
}
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