1 /*
   2  * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package javax.swing;
  26 
  27 import java.util.*;
  28 
  29 import java.io.Serializable;
  30 
  31 /**
  32  * The default model for combo boxes.
  33  *
  34  * @param <E> the type of the elements of this model
  35  *
  36  * @author Arnaud Weber
  37  * @author Tom Santos
  38  */
  39 @SuppressWarnings("serial") // Superclass is not serializable across versions
  40 public class DefaultComboBoxModel<E> extends AbstractListModel<E> implements MutableComboBoxModel<E>, Serializable {
  41     Vector<E> objects;
  42     Object selectedObject;
  43 
  44     /**
  45      * Constructs an empty DefaultComboBoxModel object.
  46      */
  47     public DefaultComboBoxModel() {
  48         objects = new Vector<E>();
  49     }
  50 
  51     /**
  52      * Constructs a DefaultComboBoxModel object initialized with
  53      * an array of objects.
  54      *
  55      * @param items  an array of Object objects
  56      */
  57     public DefaultComboBoxModel(final E items[]) {
  58         objects = new Vector<E>(items.length);
  59 
  60         int i,c;
  61         for ( i=0,c=items.length;i<c;i++ )
  62             objects.addElement(items[i]);
  63 
  64         if ( getSize() > 0 ) {
  65             selectedObject = getElementAt( 0 );
  66         }
  67     }
  68 
  69     /**
  70      * Constructs a DefaultComboBoxModel object initialized with
  71      * a vector.
  72      *
  73      * @param v  a Vector object ...
  74      */
  75     public DefaultComboBoxModel(Vector<E> v) {
  76         objects = v;
  77 
  78         if ( getSize() > 0 ) {
  79             selectedObject = getElementAt( 0 );
  80         }
  81     }
  82 
  83     // implements javax.swing.ComboBoxModel
  84     /**
  85      * Set the value of the selected item. The selected item may be null.
  86      *
  87      * @param anObject The combo box value or null for no selection.
  88      */
  89     public void setSelectedItem(Object anObject) {
  90         if ((selectedObject != null && !selectedObject.equals( anObject )) ||
  91             selectedObject == null && anObject != null) {
  92             selectedObject = anObject;
  93             fireContentsChanged(this, -1, -1);
  94         }
  95     }
  96 
  97     // implements javax.swing.ComboBoxModel
  98     public Object getSelectedItem() {
  99         return selectedObject;
 100     }
 101 
 102     // implements javax.swing.ListModel
 103     public int getSize() {
 104         return objects.size();
 105     }
 106 
 107     // implements javax.swing.ListModel
 108     public E getElementAt(int index) {
 109         if ( index >= 0 && index < objects.size() )
 110             return objects.elementAt(index);
 111         else
 112             return null;
 113     }
 114 
 115     /**
 116      * Returns the index-position of the specified object in the list.
 117      *
 118      * @param anObject the object to return the index of
 119      * @return an int representing the index position, where 0 is
 120      *         the first position
 121      */
 122     public int getIndexOf(Object anObject) {
 123         return objects.indexOf(anObject);
 124     }
 125 
 126     // implements javax.swing.MutableComboBoxModel
 127     public void addElement(E anObject) {
 128         objects.addElement(anObject);
 129         fireIntervalAdded(this,objects.size()-1, objects.size()-1);
 130         if ( objects.size() == 1 && selectedObject == null && anObject != null ) {
 131             setSelectedItem( anObject );
 132         }
 133     }
 134 
 135     // implements javax.swing.MutableComboBoxModel
 136     public void insertElementAt(E anObject,int index) {
 137         objects.insertElementAt(anObject,index);
 138         fireIntervalAdded(this, index, index);
 139     }
 140 
 141     // implements javax.swing.MutableComboBoxModel
 142     public void removeElementAt(int index) {
 143         if ( getElementAt( index ) == selectedObject ) {
 144             if ( index == 0 ) {
 145                 setSelectedItem( getSize() == 1 ? null : getElementAt( index + 1 ) );
 146             }
 147             else {
 148                 setSelectedItem( getElementAt( index - 1 ) );
 149             }
 150         }
 151 
 152         objects.removeElementAt(index);
 153 
 154         fireIntervalRemoved(this, index, index);
 155     }
 156 
 157     // implements javax.swing.MutableComboBoxModel
 158     public void removeElement(Object anObject) {
 159         int index = objects.indexOf(anObject);
 160         if ( index != -1 ) {
 161             removeElementAt(index);
 162         }
 163     }
 164 
 165     /**
 166      * Empties the list.
 167      */
 168     public void removeAllElements() {
 169         if ( objects.size() > 0 ) {
 170             int firstIndex = 0;
 171             int lastIndex = objects.size() - 1;
 172             objects.removeAllElements();
 173             selectedObject = null;
 174             fireIntervalRemoved(this, firstIndex, lastIndex);
 175         } else {
 176             selectedObject = null;
 177         }
 178     }
 179 }