jcomponent.java

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   * <p>All children of a double buffered component are painted into the
   * double buffer automatically, so only the top widget in a window needs
   * to be double buffered.</p>
   *
   * @see #setDoubleBuffered
   * @see #isDoubleBuffered
   * @see #paint
   */
  boolean doubleBuffered = true;

  /**
   * A set of flags indicating which debugging graphics facilities should
   * be enabled on this component. The values should be a combination of
   * {@link DebugGraphics#NONE_OPTION}, {@link DebugGraphics#LOG_OPTION},
   * {@link DebugGraphics#FLASH_OPTION}, or {@link
   * DebugGraphics#BUFFERED_OPTION}.
   *
   * @see #setDebugGraphicsOptions
   * @see #getDebugGraphicsOptions
   * @see DebugGraphics
   * @see #getComponentGraphics
   */
  int debugGraphicsOptions;

  /** 
   * <p>This property controls two independent behaviors simultaneously.</p>
   *
   * <p>First, it controls whether to fill the background of this widget
   * when painting its body. This affects calls to {@link
   * JComponent#paintComponent}, which in turn calls {@link
   * ComponentUI#update} on the component's {@link #ui} property. If the
   * component is opaque during this call, the background will be filled
   * before calling {@link ComponentUI#paint}. This happens merely as a
   * convenience; you may fill the component's background yourself too,
   * but there is no need to do so if you will be filling with the same
   * color.</p>
   *
   * <p>Second, it the opaque property informs swing's repaint system
   * whether it will be necessary to paint the components "underneath" this
   * component, in Z-order. If the component is opaque, it is considered to
   * completely occlude components "underneath" it, so they will not be
   * repainted along with the opaque component.</p>
   *
   * <p>The default value for this property is <code>false</code>, but most
   * components will want to set it to <code>true</code> when installing UI
   * defaults in {@link ComponentUI#installUI}.</p>
   *
   * @see #setOpaque
   * @see #isOpaque
   * @see #paintComponent
   */
  boolean opaque = false;

  /** 
   * The user interface delegate for this component. Event delivery and
   * repainting of the component are usually delegated to this object. 
   *
   * @see #setUI
   * @see #getUIClassID
   * @see #updateUI
   */
  protected ComponentUI ui;

  /**
   * A hint to the focus system that this component should or should not
   * get focus. If this is <code>false</code>, swing will not try to
   * request focus on this component; if <code>true</code>, swing might
   * try to request focus, but the request might fail. Thus it is only 
   * a hint guiding swing's behavior.
   *
   * @see #requestFocus()
   * @see #isRequestFocusEnabled
   * @see #setRequestFocusEnabled
   */
  boolean requestFocusEnabled;

  /**
   * Flag indicating behavior of this component when the mouse is dragged
   * outside the component and the mouse <em>stops moving</em>. If
   * <code>true</code>, synthetic mouse events will be delivered on regular
   * timed intervals, continuing off in the direction the mouse exited the
   * component, until the mouse is released or re-enters the component.
   *
   * @see #setAutoscrolls
   * @see #getAutoscrolls
   */
  boolean autoscrolls = false;

  /**
   * Indicates whether the current paint call is already double buffered or
   * not. 
   */
  static boolean isPaintingDoubleBuffered = false;

  /**
   * Listeners for events other than {@link PropertyChangeEvent} are
   * handled by this listener list. PropertyChangeEvents are handled in
   * {@link #changeSupport}.
   */
  protected EventListenerList listenerList = new EventListenerList();

  /** 
   * Storage for "client properties", which are key/value pairs associated
   * with this component by a "client", such as a user application or a
   * layout manager. This is lazily constructed when the component gets its
   * first client property.
   */
  private Hashtable clientProperties;
  
  private InputMap inputMap_whenFocused;
  private InputMap inputMap_whenAncestorOfFocused;
  private ComponentInputMap inputMap_whenInFocusedWindow;
  private ActionMap actionMap;
  /** @since 1.3 */
  private boolean verifyInputWhenFocusTarget;
  private InputVerifier inputVerifier;

  private TransferHandler transferHandler;

  /**
   * Indicates if this component is currently painting a tile or not.
   */
  private boolean paintingTile;

  /**
   * A temporary buffer used for fast dragging of components.
   */
  private Image dragBuffer;

  /**
   * Indicates if the dragBuffer is already initialized.
   */
  private boolean dragBufferInitialized;

  /**
   * A cached Rectangle object to be reused. Be careful when you use that,
   * so that it doesn't get modified in another context within the same
   * method call chain.
   */
  private static transient Rectangle rectCache;

  /**
   * The default locale of the component.
   * 
   * @see #getDefaultLocale
   * @see #setDefaultLocale
   */
  private static Locale defaultLocale;
  
  public static final String TOOL_TIP_TEXT_KEY = "ToolTipText";

  /**
   * Constant used to indicate that no condition has been assigned to a
   * particular action.
   *
   * @see #registerKeyboardAction(ActionListener, KeyStroke, int)
   */
  public static final int UNDEFINED_CONDITION = -1;

  /**
   * Constant used to indicate that an action should be performed only when 
   * the component has focus.
   *
   * @see #registerKeyboardAction(ActionListener, KeyStroke, int)
   */
  public static final int WHEN_FOCUSED = 0;

  /**
   * Constant used to indicate that an action should be performed only when 
   * the component is an ancestor of the component which has focus.
   *
   * @see #registerKeyboardAction(ActionListener, KeyStroke, int)
   */
  public static final int WHEN_ANCESTOR_OF_FOCUSED_COMPONENT = 1;

  /**
   * Constant used to indicate that an action should be performed only when 
   * the component is in the window which has focus.
   *
   * @see #registerKeyboardAction(ActionListener, KeyStroke, int)
   */
  public static final int WHEN_IN_FOCUSED_WINDOW = 2;

  /**
   * Indicates if this component is completely dirty or not. This is used
   * by the RepaintManager's
   * {@link RepaintManager#isCompletelyDirty(JComponent)} method.
   */
  boolean isCompletelyDirty = false;

  /**
   * Creates a new <code>JComponent</code> instance.
   */
  public JComponent()
  {
    super();
    setDropTarget(new DropTarget());
    defaultLocale = Locale.getDefault();
    debugGraphicsOptions = DebugGraphics.NONE_OPTION;
    setRequestFocusEnabled(true);
  }

  /**
   * Helper to lazily construct and return the client properties table.
   * 
   * @return The current client properties table
   *
   * @see #clientProperties
   * @see #getClientProperty
   * @see #putClientProperty
   */
  private Hashtable getClientProperties()
  {
    if (clientProperties == null)
      clientProperties = new Hashtable();
    return clientProperties;
  }

  /**
   * Get a client property associated with this component and a particular
   * key.
   *
   * @param key The key with which to look up the client property
   *
   * @return A client property associated with this object and key
   *
   * @see #clientProperties
   * @see #getClientProperties
   * @see #putClientProperty
   */
  public final Object getClientProperty(Object key)
  {
    return getClientProperties().get(key);
  }

  /**
   * Add a client property <code>value</code> to this component, associated
   * with <code>key</code>. If there is an existing client property
   * associated with <code>key</code>, it will be replaced.  A
   * {@link PropertyChangeEvent} is sent to registered listeners (with the
   * name of the property being <code>key.toString()</code>).
   *
   * @param key The key of the client property association to add
   * @param value The value of the client property association to add
   *
   * @see #clientProperties
   * @see #getClientProperties
   * @see #getClientProperty
   */
  public final void putClientProperty(Object key, Object value)
  {
    Hashtable t = getClientProperties();
    Object old = t.get(key);
    if (value != null)
      t.put(key, value);
    else
      t.remove(key);
    firePropertyChange(key.toString(), old, value);
  }

  /**
   * Unregister an <code>AncestorListener</code>.
   *
   * @param listener The listener to unregister
   * 
   * @see #addAncestorListener
   */
  public void removeAncestorListener(AncestorListener listener)
  {
    listenerList.remove(AncestorListener.class, listener);
  }

  /**
   * Unregister a <code>VetoableChangeChangeListener</code>.
   *
   * @param listener The listener to unregister
   *
   * @see #addVetoableChangeListener
   */
  public void removeVetoableChangeListener(VetoableChangeListener listener)
  {
    listenerList.remove(VetoableChangeListener.class, listener);
  }

  /**
   * Register an <code>AncestorListener</code>.
   *
   * @param listener The listener to register
   *
   * @see #removeVetoableChangeListener
   */
  public void addAncestorListener(AncestorListener listener)
  {
    listenerList.add(AncestorListener.class, listener);
  }

  /**
   * Register a <code>PropertyChangeListener</code> for a specific, named
   * property. To listen to all property changes, regardless of name, use
   * {@link #addPropertyChangeListener(PropertyChangeListener)} instead.
   *
   * @param propertyName The property name to listen to
   * @param listener The listener to register
   *
   * @see #removePropertyChangeListener(String, PropertyChangeListener)
   * @see #changeSupport
   */
  public void addPropertyChangeListener(String propertyName,
                                        PropertyChangeListener listener)
  {
    listenerList.add(PropertyChangeListener.class, listener);
  }

  /**
   * Register a <code>VetoableChangeListener</code>.
   *
   * @param listener The listener to register
   *
   * @see #removeVetoableChangeListener
   * @see #listenerList
   */
  public void addVetoableChangeListener(VetoableChangeListener listener)
  {
    listenerList.add(VetoableChangeListener.class, listener);
  }

  /**
   * Returns all registered {@link EventListener}s of the given 
   * <code>listenerType</code>.
   *
   * @param listenerType the class of listeners to filter (<code>null</code> 
   *                     not permitted).
   *                     
   * @return An array of registered listeners.
   * 
   * @throws ClassCastException if <code>listenerType</code> does not implement
   *                            the {@link EventListener} interface.
   * @throws NullPointerException if <code>listenerType</code> is 
   *                              <code>null</code>.
   *                            
   * @see #getAncestorListeners()
   * @see #listenerList
   * 
   * @since 1.3
   */
  public EventListener[] getListeners(Class listenerType)
  {
    if (listenerType == PropertyChangeListener.class)
      return getPropertyChangeListeners();
    else
      return listenerList.getListeners(listenerType);
  }

  /**
   * Return all registered <code>AncestorListener</code> objects.
   *
   * @return The set of <code>AncestorListener</code> objects in {@link
   * #listenerList}
   */
  public AncestorListener[] getAncestorListeners()
  {
    return (AncestorListener[]) getListeners(AncestorListener.class);
  }

  /**
   * Return all registered <code>VetoableChangeListener</code> objects.
   *
   * @return The set of <code>VetoableChangeListener</code> objects in {@link
   * #listenerList}
   */
  public VetoableChangeListener[] getVetoableChangeListeners()
  {
    return (VetoableChangeListener[]) getListeners(VetoableChangeListener.class);
  }

  /**
   * A variant of {@link #firePropertyChange(String,Object,Object)} 
   * for properties with <code>boolean</code> values.
   *
   * @specnote It seems that in JDK1.5 all property related methods have been 
   *           moved to java.awt.Component, except this and 2 others. We call
   *           super here. I guess this will also be removed in one of the next
   *           releases.
   */
  public void firePropertyChange(String propertyName, boolean oldValue,
                                 boolean newValue)
  {
    super.firePropertyChange(propertyName, oldValue, newValue);
  }

  /**
   * A variant of {@link #firePropertyChange(String,Object,Object)} 
   * for properties with <code>char</code> values.
   *
   * @specnote It seems that in JDK1.5 all property related methods have been 
   *           moved to java.awt.Component, except this and 2 others. We call
   *           super here. I guess this will also be removed in one of the next
   *           releases.
   */
  public void firePropertyChange(String propertyName, char oldValue,
                                 char newValue)
  {
    super.firePropertyChange(propertyName, oldValue, newValue);
  }

  /**
   * A variant of {@link #firePropertyChange(String,Object,Object)} 
   * for properties with <code>int</code> values.
   *
   * @specnote It seems that in JDK1.5 all property related methods have been 
   *           moved to java.awt.Component, except this and 2 others. We call
   *           super here. I guess this will also be removed in one of the next
   *           releases.
   */
  public void firePropertyChange(String propertyName, int oldValue,
                                 int newValue)
  {
    super.firePropertyChange(propertyName, oldValue, newValue);
  }

  /**
   * Call {@link VetoableChangeListener#vetoableChange} on all listeners
   * registered to listen to a given property. Any method which changes
   * the specified property of this component should call this method.
   *
   * @param propertyName The property which changed