287 lines
8.9 KiB
Java
287 lines
8.9 KiB
Java
/* DefaultComboBoxModel.java --
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Copyright (C) 2002, 2004, 2005, 2006, Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package javax.swing;
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import java.io.Serializable;
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import java.util.Arrays;
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import java.util.Vector;
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import javax.swing.event.ListDataEvent;
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/**
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* A model that stores a list of elements and a selected item (which may be
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* <code>null</code>). Changes to the model are signalled to listeners using
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* {@link ListDataEvent}. This model is designed for use by the
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* {@link JComboBox} component.
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*
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* @author Andrew Selkirk
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* @author Olga Rodimina
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* @author Robert Schuster
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*/
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public class DefaultComboBoxModel extends AbstractListModel
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implements MutableComboBoxModel, Serializable
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{
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private static final long serialVersionUID = 6698657703676921904L;
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/**
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* Storage for the elements in the model's list.
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*/
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private Vector list;
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/**
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* The selected item (<code>null</code> indicates no selection).
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*/
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private Object selectedItem = null;
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/**
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* Creates a new model, initially empty.
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*/
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public DefaultComboBoxModel()
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{
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list = new Vector();
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}
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/**
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* Creates a new model and initializes its item list to the values in the
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* given array. The selected item is set to the first item in the array, or
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* <code>null</code> if the array length is zero.
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*
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* @param items an array containing items for the model (<code>null</code>
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* not permitted).
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*
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* @throws NullPointerException if <code>items</code> is <code>null</code>.
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*/
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public DefaultComboBoxModel(Object[] items)
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{
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list = new Vector(Arrays.asList(items));
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if (list.size() > 0)
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selectedItem = list.get(0);
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}
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/**
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* Creates a new model and initializes its item list to the values in the
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* given vector. The selected item is set to the first item in the vector,
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* or <code>null</code> if the vector length is zero.
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*
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* @param vector a vector containing items for the model (<code>null</code>
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* not permitted).
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*
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* @throws NullPointerException if <code>vector</code> is <code>null</code>.
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*/
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public DefaultComboBoxModel(Vector<?> vector)
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{
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this.list = vector;
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if (getSize() > 0)
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selectedItem = vector.get(0);
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}
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/**
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* Adds an element to the model's item list and sends a {@link ListDataEvent}
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* to all registered listeners. If the new element is the first item added
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* to the list, and the selected item is <code>null</code>, the new element
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* is set as the selected item.
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*
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* @param object item to add to the model's item list.
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*/
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public void addElement(Object object)
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{
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list.addElement(object);
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int index = list.size() - 1;
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fireIntervalAdded(this, index, index);
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if (list.size() == 1 && selectedItem == null)
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setSelectedItem(object);
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}
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/**
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* Removes the element at the specified index from the model's item list
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* and sends a {@link ListDataEvent} to all registered listeners. If the
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* element removed was the selected item, then the preceding element becomes
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* the new selected item (or the next element, if there is no preceding
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* element).
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*
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* @param index the index of the item to remove.
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*
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* @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
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* bounds.
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*/
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public void removeElementAt(int index)
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{
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int selected = getIndexOf(selectedItem);
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if (selected == index) // choose a new selected item
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{
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if (selected > 0)
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setSelectedItem(getElementAt(selected - 1));
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else
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setSelectedItem(getElementAt(selected + 1));
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}
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list.removeElementAt(index);
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fireIntervalRemoved(this, index, index);
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}
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/**
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* Adds an element at the specified index in the model's item list
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* and sends a {@link ListDataEvent} to all registered listeners.
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*
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* @param object element to insert
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* @param index index specifing position in the list where given element
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* should be inserted.
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*
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* @throws ArrayIndexOutOfBoundsException if <code>index</code> is out of
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* bounds.
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*
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* @see #addElement(Object)
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*/
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public void insertElementAt(Object object, int index)
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{
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list.insertElementAt(object, index);
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fireIntervalAdded(this, index, index);
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}
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/**
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* Removes an element from the model's item list and sends a
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* {@link ListDataEvent} to all registered listeners. If the item to be
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* removed is the current selected item, a new selected item will be set.
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* If the element is not found in the model's item list, this method does
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* nothing.
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*
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* @param object the element to remove.
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*/
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public void removeElement(Object object)
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{
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int index = getIndexOf(object);
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if (index != -1)
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removeElementAt(index);
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}
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/**
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* Removes all the items from the model's item list, resets and selected item
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* to <code>null</code>, and sends a {@link ListDataEvent} to all registered
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* listeners.
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*/
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public void removeAllElements()
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{
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selectedItem = null;
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int size = getSize();
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if (size > 0)
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{
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list.clear();
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fireIntervalRemoved(this, 0, size - 1);
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}
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}
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/**
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* Returns the number of items in the model's item list.
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*
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* @return The number of items in the model's item list.
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*/
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public int getSize()
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{
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return list.size();
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}
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/**
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* Sets the selected item for the model and sends a {@link ListDataEvent} to
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* all registered listeners. The start and end index of the event is set to
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* -1 to indicate the model's selection has changed, and not its contents.
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*
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* @param object the new selected item (<code>null</code> permitted).
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*/
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public void setSelectedItem(Object object)
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{
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// No item is selected and object is null, so no change required.
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if (selectedItem == null && object == null)
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return;
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// object is already selected so no change required.
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if (selectedItem != null && selectedItem.equals(object))
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return;
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// Simply return if object is not in the list.
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if (object != null && getIndexOf(object) == -1)
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return;
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// Here we know that object is either an item in the list or null.
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// Handle the three change cases: selectedItem is null, object is
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// non-null; selectedItem is non-null, object is null;
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// selectedItem is non-null, object is non-null and they're not
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// equal.
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selectedItem = object;
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fireContentsChanged(this, -1, -1);
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}
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/**
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* Returns the selected item.
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*
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* @return The selected item (possibly <code>null</code>).
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*/
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public Object getSelectedItem()
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{
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return selectedItem;
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}
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/**
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* Returns the element at the specified index in the model's item list.
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*
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* @param index the element index.
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*
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* @return The element at the specified index in the model's item list, or
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* <code>null</code> if the <code>index</code> is outside the bounds
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* of the list.
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*/
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public Object getElementAt(int index)
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{
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if (index < 0 || index >= list.size())
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return null;
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return list.elementAt(index);
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}
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/**
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* Returns the index of the specified element in the model's item list.
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*
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* @param object the element.
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*
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* @return The index of the specified element in the model's item list.
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*/
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public int getIndexOf(Object object)
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{
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return list.indexOf(object);
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}
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}
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