Also see:

addItem(String)
getItem(int)
serial:

Also see:

getRows()
serial:

Also see:

isMultipleMode()
setMultipleMode(boolean)
serial:

Also see:

getSelectedIndexes()
getSelectedIndex()
serial:

Also see:

makeVisible(int)
serial:

 public List() throws HeadlessException 
{
                                                                  
        this(0, false);
}

Creates a new scrolling list. By default, there are four visible lines and multiple selections are not allowed. Note that this is a convenience method for List(0, false). Also note that the number of visible lines in the list cannot be changed after it has been created.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

Also see:

java.awt.GraphicsEnvironment#isHeadless
exception: HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

 public List(int rows) throws HeadlessException 
{
        this(rows, false);
}

Creates a new scrolling list initialized with the specified number of visible lines. By default, multiple selections are not allowed. Note that this is a convenience method for List(rows, false). Also note that the number of visible rows in the list cannot be changed after it has been created.

Parameters:

rows - the number of items to show.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

Also see:

java.awt.GraphicsEnvironment#isHeadless
exception: HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

since: JDK1.1 -

 public List(int rows,
    boolean multipleMode) throws HeadlessException 
{
                                                                                                                                                                                     
        GraphicsEnvironment.checkHeadless();
        this.rows = (rows != 0) ? rows : DEFAULT_VISIBLE_ROWS;
        this.multipleMode = multipleMode;
}

Creates a new scrolling list initialized to display the specified number of rows. Note that if zero rows are specified, then the list will be created with a default of four rows. Also note that the number of visible rows in the list cannot be changed after it has been created. If the value of multipleMode is true, then the user can select multiple items from the list. If it is false, only one item at a time can be selected.

Parameters:

rows - the number of items to show.

multipleMode - if true, then multiple selections are allowed; otherwise, only one item can be selected at a time.

Throws:

HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

Also see:

java.awt.GraphicsEnvironment#isHeadless
exception: HeadlessException - if GraphicsEnvironment.isHeadless() returns true.

 public  void add(String item) 
{
        addItem(item);
}

Adds the specified item to the end of scrolling list.

 public  void add(String item,
    int index) 
{
        addItem(item, index);
}

Adds the specified item to the the scrolling list at the position indicated by the index. The index is zero-based. If the value of the index is less than zero, or if the value of the index is greater than or equal to the number of items in the list, then the item is added to the end of the list.

 public synchronized  void addActionListener(ActionListener l) 
{
        if (l == null) {
            return;
        }
        actionListener = AWTEventMulticaster.add(actionListener, l);
        newEventsOnly = true;
}

Adds the specified action listener to receive action events from this list. Action events occur when a user double-clicks on a list item or types Enter when the list has the keyboard focus.

If listener l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

 public  void addItem(String item) 
{
        addItem(item, -1);
}

 public synchronized  void addItem(String item,
    int index) 
{
        if (index <  -1 || index  >= items.size()) {
            index = -1;
        }
        if (item == null) {
            item = "";
        }
        if (index == -1) {
            items.addElement(item);
        } else {
            items.insertElementAt(item, index);
        }
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.addItem(item, index);
        }
}

 public synchronized  void addItemListener(ItemListener l) 
{
        if (l == null) {
            return;
        }
        itemListener = AWTEventMulticaster.add(itemListener, l);
        newEventsOnly = true;
}

Adds the specified item listener to receive item events from this list. Item events are sent in response to user input, but not in response to calls to select or deselect. If listener l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

 public  void addNotify() 
{
        synchronized (getTreeLock()) {
            if (peer == null)
                peer = getToolkit().createList(this);
            super.addNotify();
        }
}

Creates the peer for the list. The peer allows us to modify the list's appearance without changing its functionality.

 public boolean allowsMultipleSelections() 
{
        return multipleMode;
}

 public synchronized  void clear() 
{
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.clear();
        }
        items = new Vector();
        selected = new int[0];
}

 String constructComponentName() 
{
        synchronized (List.class) {
            return base + nameCounter++;
        }
}

Construct a name for this component. Called by getName when the name is null.

 public int countItems() 
{
        return items.size();
}

 public  void delItem(int position) 
{
        delItems(position, position);
}

 public synchronized  void delItems(int start,
    int end) 
{
        for (int i = end; i  >= start; i--) {
            items.removeElementAt(i);
        }
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.delItems(start, end);
        }
}

 public synchronized  void deselect(int index) 
{
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            if (isMultipleMode() || (getSelectedIndex() == index)) {
                peer.deselect(index);
            }
        }
        for (int i = 0 ; i <  selected.length ; i++) {
            if (selected[i] == index) {
                int newsel[] = new int[selected.length - 1];
                System.arraycopy(selected, 0, newsel, 0, i);
                System.arraycopy(selected, i+1, newsel, i, selected.length - (i+1));
                selected = newsel;
                return;
            }
        }
}

Deselects the item at the specified index.

Note that passing out of range parameters is invalid, and will result in unspecified behavior.

If the item at the specified index is not selected, then the operation is ignored.

 boolean eventEnabled(AWTEvent e) 
{
        switch(e.id) {
          case ActionEvent.ACTION_PERFORMED:
            if ((eventMask & AWTEvent.ACTION_EVENT_MASK) != 0 ||
                actionListener != null) {
                return true;
            }
            return false;
          case ItemEvent.ITEM_STATE_CHANGED:
            if ((eventMask & AWTEvent.ITEM_EVENT_MASK) != 0 ||
                itemListener != null) {
                return true;
            }
            return false;
          default:
            break;
        }
        return super.eventEnabled(e);
}

 public AccessibleContext getAccessibleContext() 
{
        if (accessibleContext == null) {
            accessibleContext = new AccessibleAWTList();
        }
        return accessibleContext;
}

Gets the AccessibleContext associated with this List. For lists, the AccessibleContext takes the form of an AccessibleAWTList. A new AccessibleAWTList instance is created, if necessary.

 public synchronized ActionListener[] getActionListeners() 
{
        return (ActionListener[])(getListeners(ActionListener.class));
}

Returns an array of all the action listeners registered on this list.

 public String getItem(int index) 
{
        return getItemImpl(index);
}

Gets the item associated with the specified index.

 public int getItemCount() 
{
        return countItems();
}

Gets the number of items in the list.

 final String getItemImpl(int index) 
{
        return (String)items.elementAt(index);
}

 public synchronized ItemListener[] getItemListeners() 
{
        return (ItemListener[])(getListeners(ItemListener.class));
}

Returns an array of all the item listeners registered on this list.

 public synchronized String[] getItems() 
{
        String itemCopies[] = new String[items.size()];
        items.copyInto(itemCopies);
        return itemCopies;
}

Gets the items in the list.

 public T[] getListeners(Class listenerType) 
{
        EventListener l = null;
        if  (listenerType == ActionListener.class) {
            l = actionListener;
        } else if  (listenerType == ItemListener.class) {
            l = itemListener;
        } else {
            return super.getListeners(listenerType);
        }
        return AWTEventMulticaster.getListeners(l, listenerType);
}

Returns an array of all the objects currently registered as FooListeners upon this List. FooListeners are registered using the addFooListener method.

You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a List l for its item listeners with the following code:

ItemListener[] ils = (ItemListener[])(l.getListeners(ItemListener.class));

If no such listeners exist, this method returns an empty array.

 public Dimension getMinimumSize() 
{
        return minimumSize();
}

Determines the minimum size of this scrolling list.

 public Dimension getMinimumSize(int rows) 
{
        return minimumSize(rows);
}

Gets the minumum dimensions for a list with the specified number of rows.

 public Dimension getPreferredSize() 
{
        return preferredSize();
}

Gets the preferred size of this scrolling list.

 public Dimension getPreferredSize(int rows) 
{
        return preferredSize(rows);
}

Gets the preferred dimensions for a list with the specified number of rows.

 public int getRows() 
{
        return rows;
}

Gets the number of visible lines in this list. Note that once the List has been created, this number will never change.

 public synchronized int getSelectedIndex() 
{
        int sel[] = getSelectedIndexes();
        return (sel.length == 1) ? sel[0] : -1;
}

Gets the index of the selected item on the list,

 public synchronized int[] getSelectedIndexes() 
{
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            selected = ((ListPeer)peer).getSelectedIndexes();
        }
        return (int[])selected.clone();
}

Gets the selected indexes on the list.

 public synchronized String getSelectedItem() 
{
        int index = getSelectedIndex();
        return (index <  0) ? null : getItem(index);
}

Gets the selected item on this scrolling list.

 public synchronized String[] getSelectedItems() 
{
        int sel[] = getSelectedIndexes();
        String str[] = new String[sel.length];
        for (int i = 0 ; i <  sel.length ; i++) {
            str[i] = getItem(sel[i]);
        }
        return str;
}

Gets the selected items on this scrolling list.

 public Object[] getSelectedObjects() 
{
        return getSelectedItems();
}

Gets the selected items on this scrolling list in an array of Objects.

 public int getVisibleIndex() 
{
        return visibleIndex;
}

Gets the index of the item that was last made visible by the method makeVisible.

 public boolean isIndexSelected(int index) 
{
        return isSelected(index);
}

Determines if the specified item in this scrolling list is selected.

 public boolean isMultipleMode() 
{
        return allowsMultipleSelections();
}

Determines whether this list allows multiple selections.

 public boolean isSelected(int index) 
{
        int sel[] = getSelectedIndexes();
        for (int i = 0 ; i <  sel.length ; i++) {
            if (sel[i] == index) {
                return true;
            }
        }
        return false;
}

 public synchronized  void makeVisible(int index) 
{
        visibleIndex = index;
        ListPeer peer = (ListPeer)this.peer;
        if (peer != null) {
            peer.makeVisible(index);
        }
}

Makes the item at the specified index visible.

 public Dimension minimumSize() 
{
        synchronized (getTreeLock()) {
            return (rows  > 0) ? minimumSize(rows) : super.minimumSize();
        }
}

 public Dimension minimumSize(int rows) 
{
        synchronized (getTreeLock()) {
            ListPeer peer = (ListPeer)this.peer;
            return (peer != null) ?
                       peer.minimumSize(rows) :
                       super.minimumSize();
        }
}

 protected String paramString() 
{
        return super.paramString() + ",selected=" + getSelectedItem();
}

Returns the parameter string representing the state of this scrolling list. This string is useful for debugging.

 public Dimension preferredSize() 
{
        synchronized (getTreeLock()) {
            return (rows  > 0) ?
                       preferredSize(rows) :
                       super.preferredSize();
        }
}

 public Dimension preferredSize(int rows) 
{
        synchronized (getTreeLock()) {
            ListPeer peer = (ListPeer)this.peer;
            return (peer != null) ?
                       peer.preferredSize(rows) :
                       super.preferredSize();
        }
}

 protected  void processActionEvent(ActionEvent e) 
{
        ActionListener listener = actionListener;
        if (listener != null) {
            listener.actionPerformed(e);
        }
}

Processes action events occurring on this component by dispatching them to any registered ActionListener objects.

This method is not called unless action events are enabled for this component. Action events are enabled when one of the following occurs:

• An ActionListener object is registered via addActionListener.
• Action events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

 protected  void processEvent(AWTEvent e) 
{
        if (e instanceof ItemEvent) {
            processItemEvent((ItemEvent)e);
            return;
        } else if (e instanceof ActionEvent) {
            processActionEvent((ActionEvent)e);
            return;
        }
        super.processEvent(e);
}

Processes events on this scrolling list. If an event is an instance of ItemEvent, it invokes the processItemEvent method. Else, if the event is an instance of ActionEvent, it invokes processActionEvent. If the event is not an item event or an action event, it invokes processEvent on the superclass.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

 protected  void processItemEvent(ItemEvent e) 
{
        ItemListener listener = itemListener;
        if (listener != null) {
            listener.itemStateChanged(e);
        }
}

Processes item events occurring on this list by dispatching them to any registered ItemListener objects.

This method is not called unless item events are enabled for this component. Item events are enabled when one of the following occurs:

• An ItemListener object is registered via addItemListener.
• Item events are enabled via enableEvents.

Note that if the event parameter is null the behavior is unspecified and may result in an exception.

 public synchronized  void remove(String item) 
{
        int index = items.indexOf(item);
        if (index <  0) {
            throw new IllegalArgumentException("item " + item +
                                               " not found in list");
        } else {
            remove(index);
        }
}

Removes the first occurrence of an item from the list. If the specified item is selected, and is the only selected item in the list, the list is set to have no selection.

 public  void remove(int position) 
{
        delItem(position);
}

Removes the item at the specified position from this scrolling list. If the item with the specified position is selected, and is the only selected item in the list, the list is set to have no selection.

 public synchronized  void removeActionListener(ActionListener l) 
{
        if (l == null) {
            return;
        }
        actionListener = AWTEventMulticaster.remove(actionListener, l);
}

Removes the specified action listener so that it no longer receives action events from this list. Action events occur when a user double-clicks on a list item. If listener l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

 public  void removeAll() 
{
        clear();
}

Removes all items from this list.

 public synchronized  void removeItemListener(ItemListener l) 
{
        if (l == null) {
            return;
        }
        itemListener = AWTEventMulticaster.remove(itemListener, l);
}

Removes the specified item listener so that it no longer receives item events from this list. If listener l is null, no exception is thrown and no action is performed.

Refer to AWT Threading Issues for details on AWT's threading model.

 public  void removeNotify() 
{
        synchronized (getTreeLock()) {
            ListPeer peer = (ListPeer)this.peer;
            if (peer != null) {
                selected = peer.getSelectedIndexes();
            }
            super.removeNotify();
        }
}

Removes the peer for this list. The peer allows us to modify the list's appearance without changing its functionality.

 public synchronized  void replaceItem(String newValue,
    int index) 
{
        remove(index);
        add(newValue, index);
}

Replaces the item at the specified index in the scrolling list with the new string.

 public  void select(int index) 
{
        // Bug #4059614: select can't be synchronized while calling the peer,
        // because it is called from the Window Thread.  It is sufficient to
        // synchronize the code that manipulates 'selected' except for the
        // case where the peer changes.  To handle this case, we simply
        // repeat the selection process.
        ListPeer peer;
        do {
            peer = (ListPeer)this.peer;
            if (peer != null) {
                peer.select(index);
                return;
            }
            synchronized(this)
            {
                boolean alreadySelected = false;
                for (int i = 0 ; i <  selected.length ; i++) {
                    if (selected[i] == index) {
                        alreadySelected = true;
                        break;
                    }
                }
                if (!alreadySelected) {
                    if (!multipleMode) {
                        selected = new int[1];
                        selected[0] = index;
                    } else {
                        int newsel[] = new int[selected.length + 1];
                        System.arraycopy(selected, 0, newsel, 0,
                                         selected.length);
                        newsel[selected.length] = index;
                        selected = newsel;
                    }
                }
            }
        } while (peer != this.peer);
}

Selects the item at the specified index in the scrolling list.

Note that passing out of range parameters is invalid, and will result in unspecified behavior.

Note that this method should be primarily used to initially select an item in this component. Programmatically calling this method will not trigger an ItemEvent. The only way to trigger an ItemEvent is by user interaction.

 public  void setMultipleMode(boolean b) 
{
        setMultipleSelections(b);
}

Sets the flag that determines whether this list allows multiple selections. When the selection mode is changed from multiple-selection to single-selection, the selected items change as follows: If a selected item has the location cursor, only that item will remain selected. If no selected item has the location cursor, all items will be deselected.

 public synchronized  void setMultipleSelections(boolean b) 
{
        if (b != multipleMode) {
            multipleMode = b;
            ListPeer peer = (ListPeer)this.peer;
            if (peer != null) {
                peer.setMultipleSelections(b);
            }
        }
}