[Chapter 18] 18.15 java.awt.Component (JDK 1.0)

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| Chapter 18 The java.awt Package |

## 18.15 java.awt.Component (JDK 1.0)

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`Component` is the superclass of all GUI components (except menu components) in the `java.awt` package. You may not instantiate a `Component` directly; you must use a subclass.

`Component` defines many methods. Some of these are intended to be implemented by subclasses. Some are used internally by the AWT. Some are to be implemented to handle events. And many are useful utility methods for working with GUI components. `getParent()` returns the `Container` that a `Component` is contained in. `setBackground()`, `setForeground()`, and `setFont()` set the specified display attributes of a component. `hide()`, `show()`, `enable()`, and `disable()` perform the specified actions for a component. `createImage()` creates an `Image` object from a specified `ImageProducer`, or creates an offscreen image that can be draw into and used for double-buffering during animation. `Component` also has quite a few deprecated methods as a result of the Java 1.1 event model and the introduction of the JavaBeans method naming conventions. The class defines quite a few methods for handling many types of events using the 1.0 model and the 1.1 model in both its high-level and low-level forms.

    public abstract class Component extends Object implements ImageObserver, MenuContainer, Serializable {
        // Protected Constructor
            1.1  protected Component();
        // Constants
            1.1  public static final float BOTTOM_ALIGNMENT;
            1.1  public static final float CENTER_ALIGNMENT;
            1.1  public static final float LEFT_ALIGNMENT;
            1.1  public static final float RIGHT_ALIGNMENT;
            1.1  public static final float TOP_ALIGNMENT;
        // Public Instance Methods
             #  public boolean action(Event evt, Object what);
            1.1  public synchronized void add(PopupMenu popup);
            1.1  public synchronized void addComponentListener(ComponentListener l);
            1.1  public synchronized void addFocusListener(FocusListener l);
            1.1  public synchronized void addKeyListener(KeyListener l);
            1.1  public synchronized void addMouseListener(MouseListener l);
            1.1  public synchronized void addMouseMotionListener(MouseMotionListener l);
                 public void addNotify();
             #  public Rectangle bounds();
                 public int checkImage(Image image, ImageObserver observer);
                 public int checkImage(Image image, int width, int height, ImageObserver observer);
            1.1  public boolean contains(int x, int y);
            1.1  public boolean contains(Point p);
                 public Image createImage(ImageProducer producer);
                 public Image createImage(int width, int height);
             #  public void deliverEvent(Event e);
             #  public void disable();
            1.1  public final void dispatchEvent(AWTEvent e);
            1.1  public void doLayout();
             #  public void enable();
             #  public void enable(boolean b);
            1.1  public float getAlignmentX();
            1.1  public float getAlignmentY();
                 public Color getBackground();
            1.1  public Rectangle getBounds();
                 public ColorModel getColorModel();
            1.1  public Component getComponentAt(int x, int y);
            1.1  public Component getComponentAt(Point p);
            1.1  public Cursor getCursor();
                 public Font getFont();  // From MenuContainer
                 public FontMetrics getFontMetrics(Font font);
                 public Color getForeground();
                 public Graphics getGraphics();
            1.1  public Locale getLocale();
            1.1  public Point getLocation();
            1.1  public Point getLocationOnScreen();
            1.1  public Dimension getMaximumSize();
            1.1  public Dimension getMinimumSize();
            1.1  public String getName();
                 public Container getParent();
             #  public ComponentPeer getPeer();
            1.1  public Dimension getPreferredSize();
            1.1  public Dimension getSize();
                 public Toolkit getToolkit();
            1.1  public final Object getTreeLock();
             #  public boolean gotFocus(Event evt, Object what);
             #  public boolean handleEvent(Event evt);
             #  public void hide();
                public boolean imageUpdate(Image img, int flags, int x, int y, int w, int h);  // From ImageObserver
             #  public boolean inside(int x, int y);
                public void invalidate();
                public boolean isEnabled();
            1.1  public boolean isFocusTraversable();
                public boolean isShowing();
                public boolean isValid();
                public boolean isVisible();
             #  public boolean keyDown(Event evt, int key);
             #  public boolean keyUp(Event evt, int key);
             #  public void layout();
                public void list();
                public void list(PrintStream out);
                public void list(PrintStream out, int indent);
            1.1  public void list(PrintWriter out);
            1.1  public void list(PrintWriter out, int indent);
             #  public Component locate(int x, int y);
             #  public Point location();
             #  public boolean lostFocus(Event evt, Object what);
             #  public Dimension minimumSize();
             #  public boolean mouseDown(Event evt, int x, int y);
             #  public boolean mouseDrag(Event evt, int x, int y);
             #  public boolean mouseEnter(Event evt, int x, int y);
             #  public boolean mouseExit(Event evt, int x, int y);
             #  public boolean mouseMove(Event evt, int x, int y);
             #  public boolean mouseUp(Event evt, int x, int y);
             #  public void move(int x, int y);
             #  public void nextFocus();
                public void paint(Graphics g);
                public void paintAll(Graphics g);
             #  public boolean postEvent(Event e);  // From MenuContainer
             #  public Dimension preferredSize();
                public boolean prepareImage(Image image, ImageObserver observer);
                public boolean prepareImage(Image image, int width, int height, ImageObserver observer);
                public void print(Graphics g);
                public void printAll(Graphics g);
            1.1  public synchronized void remove(MenuComponent popup);  // From MenuContainer
            1.1  public synchronized void removeComponentListener(ComponentListener l);
            1.1  public synchronized void removeFocusListener(FocusListener l);
            1.1  public synchronized void removeKeyListener(KeyListener l);
            1.1  public synchronized void removeMouseListener(MouseListener l);
            1.1  public synchronized void removeMouseMotionListener(MouseMotionListener l);
                public void removeNotify();
                public void repaint();
                public void repaint(long tm);
                public void repaint(int x, int y, int width, int height);
                public void repaint(long tm, int x, int y, int width, int height);
                public void requestFocus();
             #  public void reshape(int x, int y, int width, int height);
             #  public void resize(int width, int height);
             #  public void resize(Dimension d);
                public void setBackground(Color c);
            1.1  public void setBounds(int x, int y, int width, int height);
            1.1  public void setBounds(Rectangle r);
            1.1  public synchronized void setCursor(Cursor cursor);
            1.1  public void setEnabled(boolean b);
                public synchronized void setFont(Font f);
                public void setForeground(Color c);
            1.1  public void setLocale(Locale l);
            1.1  public void setLocation(int x, int y);
            1.1  public void setLocation(Point p);
            1.1  public void setName(String name);
            1.1  public void setSize(int width, int height);
            1.1  public void setSize(Dimension d);
            1.1  public void setVisible(boolean b);
            #   public void show();
            #   public void show(boolean b);
            #   public Dimension size();
                public String toString();  // Overrides Object
            1.1  public void transferFocus();
                public void update(Graphics g);
                public void validate();
        // Protected Instance Methods
            1.1  protected final void disableEvents(long eventsToDisable);
            1.1  protected final void enableEvents(long eventsToEnable);
                protected String paramString();
            1.1  protected void processComponentEvent(ComponentEvent e);
            1.1  protected void processEvent(AWTEvent e);
            1.1  protected void processFocusEvent(FocusEvent e);
            1.1  protected void processKeyEvent(KeyEvent e);
            1.1  protected void processMouseEvent(MouseEvent e);
            1.1  protected void processMouseMotionEvent(MouseEvent e);
    }

### Extended By:

`Button, Canvas, Checkbox, Choice, Container, Label, List, Scrollbar, TextComponent`

### Passed To:

`BorderLayout.addLayoutComponent(), BorderLayout.removeLayoutComponent(), CardLayout.addLayoutComponent(), CardLayout.removeLayoutComponent(), ComponentEvent(), Container.add(), Container.addImpl(), Container.isAncestorOf(), Container.remove(), ContainerEvent(), FlowLayout.addLayoutComponent(), FlowLayout.removeLayoutComponent(), FocusEvent(), GridBagLayout.addLayoutComponent(), GridBagLayout.getConstraints(), GridBagLayout.lookupConstraints(), GridBagLayout.removeLayoutComponent(), GridBagLayout.setConstraints(), GridLayout.addLayoutComponent(), GridLayout.removeLayoutComponent(), KeyEvent(), LayoutManager.addLayoutComponent(), LayoutManager.removeLayoutComponent(), LayoutManager2.addLayoutComponent(), MediaTracker(), MouseEvent(), PaintEvent(), PopupMenu.show(), ScrollPane.addImpl(), Toolkit.createComponent(), Toolkit.getNativeContainer()`

### Returned By:

`Component.getComponentAt(), Component.locate(), ComponentEvent.getComponent(), Container.add(), Container.getComponent(), Container.getComponentAt(), Container.getComponents(), Container.locate(), ContainerEvent.getChild(), PropertyEditor.getCustomEditor(), PropertyEditorSupport.getCustomEditor(), Window.getFocusOwner()`

java.awt.Color (JDK 1.0) |  | java.awt.Container (JDK 1.0)