list.java

《移动Agent技术》一书的所有章节源代码。

            }
        } while (peer != this.peer);
    }

    /**
     * Deselects the item at the specified index.
     * <p>
     * If the item at the specified index is not selected, or if the
     * index is out of range, then the operation is ignored.
     * @param        index the position of the item to deselect.
     * @see          java.awt.List#select
     * @see          java.awt.List#getSelectedItem
     * @see          java.awt.List#isIndexSelected
     * @since        JDK1.0
     */
    public synchronized void deselect(int index) {
	ListPeer peer = (ListPeer)this.peer;
	if (peer != null) {
	    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;
	    }
	}
    }

    /**
     * Determines if the specified item in this scrolling list is
     * selected.
     * @param      index   the item to be checked.
     * @return     <code>true</code> if the specified item has been
     *                       selected; <code>false</code> otherwise.
     * @see        java.awt.List#select
     * @see        java.awt.List#deselect
     * @since      JDK1.1
     */
    public boolean isIndexSelected(int index) {
	return isSelected(index);
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>isIndexSelected(int)</code>.
     */
    public boolean isSelected(int index) {
	int sel[] = getSelectedIndexes();
	for (int i = 0 ; i < sel.length ; i++) {
	    if (sel[i] == index) {
		return true;
	    }
	}
	return false;
    }

    /**
     * Get the number of visible lines in this list.
     * @return     the number of visible lines in this scrolling list.
     * @since      JDK1.0
     */
    public int getRows() {
	return rows;
    }

    /**
     * Determines whether this list allows multiple selections.
     * @return     <code>true</code> if this list allows multiple
     *                 selections; otherwise, <code>false</code>.
     * @see        java.awt.List#setMultipleMode
     * @since      JDK1.1
     */
    public boolean isMultipleMode() {
	return allowsMultipleSelections();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>isMultipleMode()</code>.
     */
    public boolean allowsMultipleSelections() {
	return multipleMode;
    }

    /**
     * Sets the flag that determines whether this list
     * allows multiple selections.
     * @param       b   if <code>true</code> then multiple selections
     *                      are allowed; otherwise, only one item from
     *                      the list can be selected at once.
     * @see         java.awt.List#isMultipleMode
     * @since       JDK1.1
     */
    public void setMultipleMode(boolean b) {
    	setMultipleSelections(b);
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>setMultipleMode(boolean)</code>.
     */
    public synchronized void setMultipleSelections(boolean b) {
	if (b != multipleMode) {
	    multipleMode = b;
	    ListPeer peer = (ListPeer)this.peer;
	    if (peer != null) {
		peer.setMultipleSelections(b);
	    }
	}
    }

    /**
     * Gets the index of the item that was last made visible by
     * the method <code>makeVisible</code>.
     * @return      the index of the item that was last made visible.
     * @see         java.awt.List#makeVisible
     * @since       JDK1.0
     */
    public int getVisibleIndex() {
	return visibleIndex;
    }

    /**
     * Makes the item at the specified index visible.
     * @param       index    the position of the item.
     * @see         java.awt.List#getVisibleIndex
     * @since       JDK1.0
     */
    public synchronized void makeVisible(int index) {
	visibleIndex = index;
	ListPeer peer = (ListPeer)this.peer;
	if (peer != null) {
	    peer.makeVisible(index);
	}
    }

    /**
     * Gets the preferred dimensions for a list with the specified
     * number of rows.
     * @param      rows    number of rows in the list.
     * @return     the preferred dimensions for displaying this scrolling list.
     * @see        java.awt.Component#getPreferredSize
     * @since      JDK1.1
     */
    public Dimension getPreferredSize(int rows) {
	return preferredSize(rows);
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getPreferredSize(int)</code>.
     */
    public Dimension preferredSize(int rows) {
        synchronized (getTreeLock()) {
  	    ListPeer peer = (ListPeer)this.peer;
 	    return (peer != null) ?
  		       peer.preferredSize(rows) :
  		       super.preferredSize();
  	}
    }

    /**
     * Gets the preferred size of this scrolling list.
     * @return     the preferred dimensions for displaying this scrolling list.
     * @see        java.awt.Component#getPreferredSize
     * @since      JDK1.1
     */
    public Dimension getPreferredSize() {
	return preferredSize();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getPreferredSize()</code>.
     */
    public Dimension preferredSize() {
	synchronized (getTreeLock()) {
	    return (rows > 0) ?
		       preferredSize(rows) :
		       super.preferredSize();
	}
    }

    /**
     * Gets the minumum dimensions for a list with the specified
     * number of rows.
     * @param      rows    number of rows in the list.
     * @return     the minimum dimensions for displaying this scrolling list.
     * @see        java.awt.Component#getMinimumSize
     * @since      JDK1.1
     */
    public Dimension getMinimumSize(int rows) {
	return minimumSize(rows);
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getMinimumSize(int)</code>.
     */
    public Dimension minimumSize(int rows) {
  	synchronized (getTreeLock()) {
  	    ListPeer peer = (ListPeer)this.peer;
 	    return (peer != null) ?
     	    	       peer.minimumSize(rows) :
 		       super.minimumSize();
  	}
    }

    /**
     * Determines the minimum size of this scrolling list.
     * @return       the minimum dimensions needed
     *                        to display this scrolling list.
     * @see          java.awt.Component#getMinimumSize()
     * @since        JDK1.1
     */
    public Dimension getMinimumSize() {
	return minimumSize();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * replaced by <code>getMinimumSize()</code>.
     */
    public Dimension minimumSize() {
	synchronized (getTreeLock()) {
	    return (rows > 0) ? minimumSize(rows) : super.minimumSize();
	}
    }

    /**
     * Adds the specified item listener to receive item events from
     * this list.
     * @param         l the item listener.
     * @see           java.awt.event.ItemEvent
     * @see           java.awt.event.ItemListener
     * @see           java.awt.List#removeItemListener
     * @since         JDK1.1
     */
    public synchronized void addItemListener(ItemListener l) {
        itemListener = AWTEventMulticaster.add(itemListener, l);
        newEventsOnly = true;
    }

    /**
     * Removes the specified item listener so that it no longer
     * receives item events from this list.
     * @param         l the item listener.
     * @see           java.awt.event.ItemEvent
     * @see           java.awt.event.ItemListener
     * @see           java.awt.List#addItemListener
     * @since         JDK1.1
     */
    public synchronized void removeItemListener(ItemListener l) {
        itemListener = AWTEventMulticaster.remove(itemListener, l);
    }

    /**
     * Adds the specified action listener to receive action events from
     * this list. Action events occur when a user double-clicks
     * on a list item.
     * @param         l the action listener.
     * @see           java.awt.event.ActionEvent
     * @see           java.awt.event.ActionListener
     * @see           java.awt.List#removeActionListener
     * @since         JDK1.1
     */
    public synchronized void addActionListener(ActionListener l) {
	actionListener = AWTEventMulticaster.add(actionListener, l);
        newEventsOnly = true;
    }

    /**
     * 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.
     * @param         l     the action listener.
     * @see           java.awt.event.ActionEvent
     * @see           java.awt.event.ActionListener
     * @see           java.awt.List#addActionListener
     * @since         JDK1.1
     */
    public synchronized void removeActionListener(ActionListener l) {
	actionListener = AWTEventMulticaster.remove(actionListener, l);
    }

    // REMIND: remove when filtering is done at lower level
    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);
    }

    /**
     * Processes events on this scrolling list. If an event is
     * an instance of <code>ItemEvent</code>, it invokes the
     * <code>processItemEvent</code> method. Else, if the
     * event is an instance of <code>ActionEvent</code>,
     * it invokes <code>processActionEvent</code>.
     * If the event is not an item event or an action event,
     * it invokes <code>processEvent</code> on the superclass.
     * @param        e the event.
     * @see          java.awt.event.ActionEvent
     * @see          java.awt.event.ItemEvent
     * @see          java.awt.List#processActionEvent
     * @see          java.awt.List#processItemEvent
     * @since        JDK1.1
     */
    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 item events occurring on this list by
     * dispatching them to any registered
     * <code>ItemListener</code> objects.
     * <p>
     * This method is not called unless item events are
     * enabled for this component. Item events are enabled
     * when one of the following occurs:
     * <p><ul>
     * <li>An <code>ItemListener</code> object is registered
     * via <code>addItemListener</code>.
     * <li>Item events are enabled via <code>enableEvents</code>.
     * </ul>
     * @param       e the item event.
     * @see         java.awt.event.ItemEvent
     * @see         java.awt.event.ItemListener
     * @see         java.awt.List#addItemListener
     * @see         java.awt.Component#enableEvents
     * @since       JDK1.1
     */
    protected void processItemEvent(ItemEvent e) {
        if (itemListener != null) {
            itemListener.itemStateChanged(e);
        }
    }

    /**
     * Processes action events occurring on this component
     * by dispatching them to any registered
     * <code>ActionListener</code> objects.
     * <p>
     * This method is not called unless action events are
     * enabled for this component. Action events are enabled
     * when one of the following occurs:
     * <p><ul>
     * <li>An <code>ActionListener</code> object is registered
     * via <code>addActionListener</code>.
     * <li>Action events are enabled via <code>enableEvents</code>.
     * </ul>
     * @param       e the action event.
     * @see         java.awt.event.ActionEvent
     * @see         java.awt.event.ActionListener
     * @see         java.awt.List#addActionListener
     * @see         java.awt.Component#enableEvents
     * @since       JDK1.1
     */
    protected void processActionEvent(ActionEvent e) {
        if (actionListener != null) {
            actionListener.actionPerformed(e);
        }
    }

    /**
     * Returns the parameter string representing the state of this
     * scrolling list. This string is useful for debugging.
     * @return    the parameter string of this scrolling list.
     * @since     JDK1.0
     */
    protected String paramString() {
	return super.paramString() + ",selected=" + getSelectedItem();
    }

    /**
     * @deprecated As of JDK version 1.1,
     * Not for public use in the future.
     * This method is expected to be retained only as a package
     * private method.
     */
    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);
	}
    }

    /*
     * Serialization support.  Since the value of the selected
     * field isn't neccessarily up to date we sync it up with the
     * peer before serializing.
     */

    private int listSerializedDataVersion = 1;


    private void writeObject(ObjectOutputStream s)
      throws IOException
    {
      synchronized (this) {
	ListPeer peer = (ListPeer)this.peer;
	if (peer != null) {
	  selected = peer.getSelectedIndexes();
	}
      }
      s.defaultWriteObject();

      AWTEventMulticaster.save(s, itemListenerK, itemListener);
      AWTEventMulticaster.save(s, actionListenerK, actionListener);
      s.writeObject(null);
    }


    private void readObject(ObjectInputStream s)
      throws ClassNotFoundException, IOException
    {
      s.defaultReadObject();

      Object keyOrNull;
      while(null != (keyOrNull = s.readObject())) {
	String key = ((String)keyOrNull).intern();

	if (itemListenerK == key)
	  addItemListener((ItemListener)(s.readObject()));

	else if (actionListenerK == key)
	  addActionListener((ActionListener)(s.readObject()));

	else // skip value for unrecognized key
	  s.readObject();
      }
    }


}