gcc/libjava/javax/swing/DefaultComboBoxModel.java

/* DefaultComboBoxModel.java --
   Copyright (C) 2002, 2004 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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permission to link this library with independent modules to produce an
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package javax.swing;

import java.io.Serializable;
import java.util.Arrays;
import java.util.Vector;


/**
 * DefaultComboBoxModel is a data model for JComboBox. This model keeps track
 * of elements contained in the JComboBox as well as the current combo box
 * selection. Whenever selection in the JComboBox changes, the ComboBoxModel
 * will fire ListDataEvents to ComboBox's ListDataListeners.
 *
 * @author Andrew Selkirk
 * @author Olga Rodimina
 * @author Robert Schuster
 * @version 1.0
 */
public class DefaultComboBoxModel extends AbstractListModel
  implements MutableComboBoxModel, Serializable
{
  private static final long serialVersionUID = 6698657703676921904L;

  /**
   * List containing items in the combo box
   */
  private Vector list;

  /**
   * Currently selected item in the combo box list
   */
  private Object selectedItem = null;

  /**
   * Constructor DefaultComboBoxModel. Create empty JComboBox.
   */
  public DefaultComboBoxModel()
  {
    list = new Vector();
  }

  /**
   * Constructs new DefaultComboBoxModel object and initializes its item list
   * to values in the given array.
   *
   * @param items array containing items of the combo box.
   */
  public DefaultComboBoxModel(Object[] items)
  {
    list = new Vector(Arrays.asList(items));
  }

  /**
   * Consturcts new DefaultComboBoxModel object and initializes its item list
   * to values in the given vector.
   *
   * @param vector Vector containing items for this combo box.
   */
  public DefaultComboBoxModel(Vector vector)
  {
    this.list = vector;
  }

  /**
   * This method adds element to the combo box list. It fires ListDataEvent
   * indicating that component was added to the combo box  to all of the
   * JComboBox's registered ListDataListeners.
   *
   * @param object item to add to the combo box list
   */
  public void addElement(Object object)
  {
    list.add(object);
    fireIntervalAdded(this, list.size(), list.size());
  }

  /**
   * This method removes element at the specified index from the combo box
   * list. It fires ListDataEvent indicating that component was removed from
   * the combo box list to all of the JComboBox's registered
   * ListDataListeners.
   *
   * @param index index specifying location of the element to remove in the
   *        combo box list.
   */
  public void removeElementAt(int index)
  {
    list.remove(index);
    fireIntervalRemoved(this, index, index);
  }

  /**
   * This method inserts given object to the combo box list at the specified
   * index. It fires ListDataEvent indicating that component was inserted to
   * the combo box list to all of the JComboBox's registered
   * ListDataListeners.
   *
   * @param object element to insert
   * @param index index specifing position in the list where given element
   *        should be inserted.
   */
  public void insertElementAt(Object object, int index)
  {
    list.insertElementAt(object, index);
    fireIntervalAdded(this, index, index);
  }

  /**
   * Removes given object from the combo box list. It fires ListDataEvent
   * indicating that component was removed from the combo box list to all of
   * the JComboBox's registered ListDataListeners.
   *
   * @param object Element that will be removed from the combo box list
   */
  public void removeElement(Object object)
  {
    int index = getIndexOf(object);
    if (index != -1)
      removeElementAt(index);
  }

  /**
   * Removes all the items from the JComboBox's item list. It fires
   * ListDataEvent indicating that all the elements were removed from the
   * combo box list to all of the JComboBox's registered ListDataListeners.
   */
  public void removeAllElements()
  {
    int listSize = getSize();
    list.clear();
    fireIntervalAdded(this, 0, listSize - 1);
  }

  /**
   * Returns number of items in the combo box list
   *
   * @return number of items in the combo box list
   */
  public int getSize()
  {
    return list.size();
  }

  /**
   * Selects given object in the combo box list. This method fires
   * ListDataEvent to all registered ListDataListeners of the JComboBox. The
   * start and end index of the event is set to -1 to indicate combo box's
   * selection has changed, and not its contents.
   * 
   * <p>If the given object is not contained in the combo box list then nothing
   * happens.</p>
   *
   * @param object item to select in the JComboBox
   */
  public void setSelectedItem(Object object)
  {
    
    /* Updates the selected item only if the given object
     * is null or in the list (this is how the JDK behaves).
     */ 
    if(object == null || list.contains(object)) {
	selectedItem = object;
	fireContentsChanged(this, -1, -1);
    }
  	
  }

  /**
   * Returns currently selected item in the combo box list
   *
   * @return currently selected item in the combo box list
   */
  public Object getSelectedItem()
  {
    return selectedItem;
  }

  /**
   * Returns element in the combo box list located at the given index
   *
   * @param index specifying location of the element in the list
   *
   * @return return element in the combo box list located at the given index
   */
  public Object getElementAt(int index)
  {
    return list.elementAt(index);
  }

  /**
   * Returns index of the specified object in the combo box list.
   *
   * @param object element to look for in the combo box list .
   *
   * @return Index specifying position of the specified element in combo box
   *         list.
   */
  public int getIndexOf(Object object)
  {
    return list.indexOf(object);
  }
}