menucomponent.java

gcc的组建

   */
  public FontMetrics getFontMetrics(Font font)
  {
    return MenuComponent.this.getToolkit().getFontMetrics(font);
  }

  /**
   * Returns the foreground color of the component, or null
   * if this property is unsupported.
   * <br />
   * <br />
   * This abstract class knows nothing about how the component
   * is drawn on screen, so this method simply returns the
   * default system text color used for rendering menus.
   * Concrete subclasses which handle the drawing of an onscreen
   * menu component should override this method and provide
   * the appropriate information.
   *
   * @return the default system text color for menus.
   * @see #setForeground(java.awt.Color)
   */
  public Color getForeground()
  {
    return SystemColor.menuText;
  }

  /**
   * Returns the locale currently in use by this component.
   * <br />
   * <br />
   * This abstract class has no property relating to the
   * locale used by the component, so this method simply
   * returns the default locale for the current instance
   * of the Java Virtual Machine (JVM).  Concrete subclasses
   * which maintain such a property should override this method
   * and provide the locale information more accurately.
   *
   * @return the default locale for this JVM instance.
   */
  public Locale getLocale()
  {
    return Locale.getDefault();
  }

  /**
   * Returns the location of the component, with co-ordinates
   * relative to the parent component and using the co-ordinate
   * space of the screen.  Thus, the point (0,0) is the upper
   * left corner of the parent component.
   * <br />
   * <br />
   * Please note that this method depends on a correctly implemented
   * version of the <code>getBounds()</code> method.  Subclasses
   * must provide the bounding rectangle via <code>getBounds()</code>
   * in order for this method to work.  
   *
   * @return the location of the component, relative to its parent.
   * @see #setLocation(java.awt.Point)
   */
  public Point getLocation()
  {
    /* Simply return the location of the bounding rectangle */
    return getBounds().getLocation();
  }

  /**
   * Returns the location of the component, with co-ordinates
   * relative to the screen.  Thus, the point (0,0) is the upper
   * left corner of the screen.  null is returned if the component
   * is either not on screen or if this property is unsupported.
   * <br />
   * <br />
   * This abstract class knows nothing about how the component
   * is drawn on screen, so this method simply returns null.
   * Concrete subclasses which handle the drawing of an onscreen
   * menu component should override this method and provide
   * the appropriate information.
   *
   * @return the location of the component, relative to the screen.
   */
  public Point getLocationOnScreen()
  {
    return null;
  }

  /**
   * Returns the size of the component.
   * <br />
   * <br />
   * Please note that this method depends on a correctly implemented
   * version of the <code>getBounds()</code> method.  Subclasses
   * must provide the bounding rectangle via <code>getBounds()</code>
   * in order for this method to work.  
   *
   * @return the size of the component.
   * @see #setSize(java.awt.Dimension)
   */
  public Dimension getSize()
  {
    /* Simply return the size of the bounding rectangle */
    return getBounds().getSize();
  }

  /**
   * Returns true if the accessible child specified by the supplied index
   * is currently selected.
   * <br />
   * <br />
   * As the existence of children can not be determined from
   * this abstract class, the implementation of this method
   * is left to subclasses.
   *
   * @param index the index of the accessible child to check for selection.
   * @return false.
   */
  public boolean isAccessibleChildSelected(int index)
  {
    return false;
  }

  /**
   * Returns true if this component is currently enabled.
   * <br />
   * <br />
   * As this abstract component has no properties related to
   * its enabled or disabled state, the implementation of this
   * method is left to subclasses.
   *
   * @return false.
   * @see #setEnabled(boolean)
   */
  public boolean isEnabled()
  {
    return false;
  }

  /**
   * Returns true if this component is included in the traversal
   * of the current focus from one component to the other.
   * <br />
   * <br />
   * As this abstract component has no properties related to
   * its ability to accept the focus, the implementation of this
   * method is left to subclasses.
   *
   * @return false.
   */
  public boolean isFocusTraversable()
  {
    return false;
  }

  /**
   * Returns true if the component is being shown on screen.
   * A component is determined to be shown if it is visible,
   * and each parent component is also visible.  Please note
   * that, even when a component is showing, it may still be
   * obscured by other components in front.  This method only
   * determines if the component is being drawn on the screen.
   * <br />
   * <br />
   * As this abstract component and its parent have no properties
   * relating to visibility, the implementation of this method is
   * left to subclasses.
   *
   * @return false.
   * @see #isVisible()
   */
  public boolean isShowing()
  {
    return false;
  }

  /**
   * Returns true if the component is visible.  A component may
   * be visible but not drawn on the screen if one of its parent
   * components is not visible.  To determine if the component is
   * actually drawn on screen, <code>isShowing()</code> should be
   * used.
   * <br />
   * <br />
   * As this abstract component has no properties relating to its
   * visibility, the implementation of this method is left to subclasses.
   *
   * @return false.
   * @see #isShowing()
   * @see #setVisible(boolean)
   */
  public boolean isVisible()
  {
    return false;
  }

  /**
   * Removes the accessible child specified by the supplied index from
   * the list of currently selected children.  If the child specified
   * is not selected, nothing happens.
   * <br />
   * <br />
   * As the existence of children can not be determined from
   * this abstract class, the implementation of this method
   * is left to subclasses.
   *
   * @param index the index of the <code>Accessible</code> child.
   */
  public void removeAccessibleSelection(int index)
  {
    /* Subclasses with children should implement this */
  }

  /**
   * Removes the specified focus listener from the list of registered
   * focus listeners for this component.
   *
   * @param listener the listener to remove.
   */
  public void removeFocusListener(FocusListener listener)
  {
    /* Remove the focus listener from the chain */
    focusListener = AWTEventMulticaster.remove(focusListener, listener);
  }

  /**
   * Requests that this component gains focus.  This depends on the
   * component being focus traversable.
   * <br />
   * <br />
   * As this abstract component has no properties relating to its
   * focus traversability, or access to a peer with request focusing
   * abilities, the implementation of this method is left to subclasses.
   */
  public void requestFocus()
  {
    /* Ignored */
  }

  /**
   * Selects all <code>Accessible</code> children of this component which
   * it is possible to select.  The component needs to support multiple
   * selections.
   * <br />
   * <br />
   * This abstract component provides a simplistic implementation of this
   * method, which ignores the ability of the component to support multiple
   * selections and simply uses <code>addAccessibleSelection</code> to
   * add each <code>Accessible</code> child to the selection.  The last
   * <code>Accessible</code> component is thus selected for components
   * which don't support multiple selections.  Concrete implementations should
   * override this with a more appopriate and efficient implementation, which
   * properly takes into account the ability of the component to support multiple
   * selections. 
   */
  public void selectAllAccessibleSelection()
  {
    /* Simply call addAccessibleSelection() on all accessible children */
    for (int a = 0; a < getAccessibleChildrenCount(); ++a)
      {
        addAccessibleSelection(a);
      }
  }

  /**
   * Sets the background color of the component to that specified.
   * Unspecified behaviour occurs when null is given as the new
   * background color.
   * <br />
   * <br />
   * This abstract class knows nothing about how the component
   * is drawn on screen, so this method simply ignores the supplied
   * color and continues to use the default system color.   
   * Concrete subclasses which handle the drawing of an onscreen
   * menu component should override this method and provide
   * the appropriate information.
   *
   * @param color the new color to use for the background.
   * @see #getBackground()
   */
  public void setBackground(Color color)
  {
    /* Ignored */
  }

  /**
   * Sets the height and width of the component, and its position
   * relative to this component's parent, to the values specified
   * by the supplied rectangle.  Unspecified behaviour occurs when
   * null is given as the new bounds.
   * <br />
   * <br />
   * This abstract class knows nothing about how the component
   * is drawn on screen, so this method simply ignores the new
   * rectangle and continues to return null from <code>getBounds()</code>.
   * Concrete subclasses which handle the drawing of an onscreen
   * menu component should override this method and provide
   * the appropriate information.
   *
   * @param rectangle a rectangle which specifies the new bounds of
   *        the component.
   * @see #getBounds()
   */
  public void setBounds(Rectangle rectangle)
  {
    /* Ignored */
  }

  /**
   * Sets the <code>Cursor</code> used when the pointer is positioned over the
   * component.  Unspecified behaviour occurs when null is given as the new
   * cursor.
   * <br />
   * <br />
   * This abstract class knows nothing about how the component
   * is drawn on screen, so this method simply ignores the new cursor
   * and continues to return the default system cursor.  Concrete
   * subclasses which handle the drawing of an onscreen menu component
   * may override this method and provide the appropriate information.
   *
   * @param cursor the new cursor to use.
   * @see #getCursor()
   */
  public void setCursor(Cursor cursor)
  {
    /* Ignored */
  }

  /**
   * Sets the enabled/disabled state of this component.
   * <br />
   * <br />
   * As this abstract component has no properties related to
   * its enabled or disabled state, the implementation of this
   * method is left to subclasses.
   *
   * @param enabled true if the component should be enabled,
   *        false otherwise.
   * @see #isEnabled()
   */
  public void setEnabled(boolean enabled)
  {
    /* Ignored */
  }

  /**
   * Sets the <code>Font</code> used for text created by this component.
   * Unspecified behaviour occurs when null is given as the new
   * font.
   *
   * @param font the new font to use for text.
   * @see #getFont()
   */
  public void setFont(Font font)
  {
    /* Call the method of the enclosing component */
    MenuComponent.this.setFont(font);
  }

  /**
   * Sets the foreground color of the component to that specified.
   * Unspecified behaviour occurs when null is given as the new
   * background color.
   * <br />
   * <br />
   * This abstract class knows nothing about how the component
   * is drawn on screen, so this method simply ignores the supplied
   * color and continues to return the default system text color used
   * for rendering menus.
   * Concrete subclasses which handle the drawing of an onscreen
   * menu component should override this method and provide
   * the appropriate information.
   *
   * @param color the new foreground color.
   * @see #getForeground()
   */
  public void setForeground(Color color)
  {
    /* Ignored */
  }

  /**
   * Sets the location of the component, with co-ordinates
   * relative to the parent component and using the co-ordinate
   * space of the screen.  Thus, the point (0,0) is the upper
   * left corner of the parent component.
   * <br />
   * <br />
   * Please note that this method depends on a correctly implemented
   * version of the <code>getBounds()</code> method.  Subclasses
   * must provide the bounding rectangle via <code>getBounds()</code>
   * in order for this method to work.  
   *
   * @param point the location of the component, relative to its parent.
   * @see #getLocation()
   */
  public void setLocation(Point point)
  {
    getBounds().setLocation(point);
  }

  /**
   * Sets the size of the component.
   * <br />
   * <br />
   * Please note that this method depends on a correctly implemented
   * version of the <code>getBounds()</code> method.  Subclasses
   * must provide the bounding rectangle via <code>getBounds()</code>
   * in order for this method to work.  
   *
   * @param size the new size of the component.
   * @see #getSize()
   */
  public void setSize(Dimension size)
  {
    getBounds().setSize(size);
  }

  /**
   * Sets the visibility state of the component.  A component may
   * be visible but not drawn on the screen if one of its parent
   * components is not visible.  To determine if the component is
   * actually drawn on screen, <code>isShowing()</code> should be
   * used.
   * <br />
   * <br />
   * As this abstract component has no properties relating to its
   * visibility, the implementation of this method is left to subclasses.
   *
   * @param visibility the new visibility of the component -- true if
   *        the component is visible, false if not.
   * @see #isShowing()
   * @see #isVisible()
   */
  public void setVisible(boolean visibility)
  {
    /* Ignored */
  }

} /* class AccessibleAWTMenuComponent */
          

} // class MenuComponent