The class used to obtain the accessible role for this object, as well as implementing many of the methods in the AccessibleContainer interface. 

Also see:

getComponent
getComponents
getComponentCount

Also see:

add
getComponents

Also see:

doLayout
setLayout
getLayout

Also see:

getMouseEventTarget(int, int, boolean, boolean, boolean)

Also see:

getMouseEventTarget(int, int, boolean, boolean, boolean)

 public Container() 
{
     
        /* ensure that the necessary native libraries are loaded */
        Toolkit.loadLibraries();
        if (!GraphicsEnvironment.isHeadless()) {
            initIDs();
        }
}

Constructs a new Container. Containers can be extended directly, but are lightweight in this case and must be contained by a parent somewhere higher up in the component tree that is native. (such as Frame for example).

 public Component add(Component comp) 
{
        addImpl(comp, null, -1);
        return comp;
}

Appends the specified component to the end of this container. This is a convenience method for #addImpl .

Note: If a component has been added to a container that has been displayed, validate must be called on that container to display the new component. If multiple components are being added, you can improve efficiency by calling validate only once, after all the components have been added.

 public Component add(String name,
    Component comp) 
{
        addImpl(comp, name, -1);
        return comp;
}

Adds the specified component to this container. This is a convenience method for #addImpl .

This method is obsolete as of 1.1. Please use the method add(Component, Object) instead.

 public Component add(Component comp,
    int index) 
{
        addImpl(comp, null, index);
        return comp;
}

Adds the specified component to this container at the given position. This is a convenience method for #addImpl .

Note: If a component has been added to a container that has been displayed, validate must be called on that container to display the new component. If multiple components are being added, you can improve efficiency by calling validate only once, after all the components have been added.

 public  void add(Component comp,
    Object constraints) 
{
        addImpl(comp, constraints, -1);
}

Adds the specified component to the end of this container. Also notifies the layout manager to add the component to this container's layout using the specified constraints object. This is a convenience method for #addImpl .

Note: If a component has been added to a container that has been displayed, validate must be called on that container to display the new component. If multiple components are being added, you can improve efficiency by calling validate only once, after all the components have been added.

 public  void add(Component comp,
    Object constraints,
    int index) 
{
       addImpl(comp, constraints, index);
}

Adds the specified component to this container with the specified constraints at the specified index. Also notifies the layout manager to add the component to the this container's layout using the specified constraints object. This is a convenience method for #addImpl .

Note: If a component has been added to a container that has been displayed, validate must be called on that container to display the new component. If multiple components are being added, you can improve efficiency by calling validate only once, after all the components have been added.

 public synchronized  void addContainerListener(ContainerListener l) 
{
        if (l == null) {
            return;
        }
        containerListener = AWTEventMulticaster.add(containerListener, l);
        newEventsOnly = true;
}

Adds the specified container listener to receive container events from this container. If l is null, no exception is thrown and no action is performed.

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

 protected  void addImpl(Component comp,
    Object constraints,
    int index) 
{
        synchronized (getTreeLock()) {
            /* Check for correct arguments:  index in bounds,
             * comp cannot be one of this container's parents,
             * and comp cannot be a window.
             * comp and container must be on the same GraphicsDevice.
             * if comp is container, all sub-components must be on
             * same GraphicsDevice.
             */
            GraphicsConfiguration thisGC = this.getGraphicsConfiguration();
            if (index  > ncomponents || (index <  0 && index != -1)) {
                throw new IllegalArgumentException(
                          "illegal component position");
            }
        if (comp instanceof Container) {
            for (Container cn = this; cn != null; cn=cn.parent) {
                if (cn == comp) {
                throw new IllegalArgumentException(
                      "adding container's parent to itself");
                }
            }
            if (comp instanceof Window) {
                throw new IllegalArgumentException(
                       "adding a window to a container");
            }
        }
        if (thisGC != null) {
            comp.checkGD(thisGC.getDevice().getIDstring());
        }
            /* Reparent the component and tidy up the tree's state. */
            if (comp.parent != null) {
                comp.parent.remove(comp);
                    if (index  > ncomponents) {
                        throw new IllegalArgumentException("illegal component position");
                    }
            }
            /* Add component to list; allocate new array if necessary. */
            if (ncomponents == component.length) {
                component = Arrays.copyOf(component, ncomponents * 2 + 1);
            }
            if (index == -1 || index == ncomponents) {
                component[ncomponents++] = comp;
            } else {
                System.arraycopy(component, index, component,
                                 index + 1, ncomponents - index);
                component[index] = comp;
                ncomponents++;
            }
            comp.parent = this;
            adjustListeningChildren(AWTEvent.HIERARCHY_EVENT_MASK,
                comp.numListening(AWTEvent.HIERARCHY_EVENT_MASK));
            adjustListeningChildren(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK,
                comp.numListening(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));
            adjustDescendants(comp.countHierarchyMembers());
            if (valid) {
                invalidate();
            }
            if (peer != null) {
                comp.addNotify();
            }
            /* Notify the layout manager of the added component. */
            if (layoutMgr != null) {
                if (layoutMgr instanceof LayoutManager2) {
                    ((LayoutManager2)layoutMgr).addLayoutComponent(comp, constraints);
                } else if (constraints instanceof String) {
                    layoutMgr.addLayoutComponent((String)constraints, comp);
                }
            }
            if (containerListener != null ||
                (eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0 ||
                Toolkit.enabledOnToolkit(AWTEvent.CONTAINER_EVENT_MASK)) {
                ContainerEvent e = new ContainerEvent(this,
                                     ContainerEvent.COMPONENT_ADDED,
                                     comp);
                dispatchEvent(e);
            }
            comp.createHierarchyEvents(HierarchyEvent.HIERARCHY_CHANGED, comp,
                                       this, HierarchyEvent.PARENT_CHANGED,
                                       Toolkit.enabledOnToolkit(AWTEvent.HIERARCHY_EVENT_MASK));
            if (peer != null && layoutMgr == null && isVisible()) {
                updateCursorImmediately();
            }
        }
}

Adds the specified component to this container at the specified index. This method also notifies the layout manager to add the component to this container's layout using the specified constraints object via the addLayoutComponent method.

The constraints are defined by the particular layout manager being used. For example, the BorderLayout class defines five constraints: BorderLayout.NORTH, BorderLayout.SOUTH, BorderLayout.EAST, BorderLayout.WEST, and BorderLayout.CENTER.

The GridBagLayout class requires a GridBagConstraints object. Failure to pass the correct type of constraints object results in an IllegalArgumentException.

If the current layout manager implements {@code LayoutManager2}, then LayoutManager2#addLayoutComponent(Component,Object) is invoked on it. If the current layout manager does not implement {@code LayoutManager2}, and constraints is a {@code String}, then LayoutManager#addLayoutComponent(String,Component) is invoked on it.

If the component is not an ancestor of this container and has a non-null parent, it is removed from its current parent before it is added to this container.

This is the method to override if a program needs to track every add request to a container as all other add methods defer to this one. An overriding method should usually include a call to the superclass's version of the method:

super.addImpl(comp, constraints, index)

 public  void addNotify() 
{
        synchronized (getTreeLock()) {
            // addNotify() on the children may cause proxy event enabling
            // on this instance, so we first call super.addNotify() and
            // possibly create an lightweight event dispatcher before calling
            // addNotify() on the children which may be lightweight.
            super.addNotify();
            if (! (peer instanceof LightweightPeer)) {
                dispatcher = new LightweightDispatcher(this);
            }
            int ncomponents = this.ncomponents;
            Component component[] = this.component;
            for (int i = 0 ; i <  ncomponents ; i++) {
                component[i].addNotify();
            }
            // Update stacking order if native platform allows
            ContainerPeer cpeer = (ContainerPeer)peer;
            if (cpeer.isRestackSupported()) {
                cpeer.restack();
            }
        }
}

Makes this Container displayable by connecting it to a native screen resource. Making a container displayable will cause all of its children to be made displayable. This method is called internally by the toolkit and should not be called directly by programs.

 public  void addPropertyChangeListener(PropertyChangeListener listener) 
{
        super.addPropertyChangeListener(listener);
}

Adds a PropertyChangeListener to the listener list. The listener is registered for all bound properties of this class, including the following:
• this Container's font ("font")
• this Container's background color ("background")
• this Container's foreground color ("foreground")
• this Container's focusability ("focusable")
• this Container's focus traversal keys enabled state ("focusTraversalKeysEnabled")
• this Container's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
• this Container's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
• this Container's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
• this Container's Set of DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleFocusTraversalKeys")
• this Container's focus traversal policy ("focusTraversalPolicy")
• this Container's focus-cycle-root state ("focusCycleRoot")
Note that if this Container is inheriting a bound property, then no event will be fired in response to a change in the inherited property.

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

 public  void addPropertyChangeListener(String propertyName,
    PropertyChangeListener listener) 
{
        super.addPropertyChangeListener(propertyName, listener);
}

Adds a PropertyChangeListener to the listener list for a specific property. The specified property may be user-defined, or one of the following defaults:
• this Container's font ("font")
• this Container's background color ("background")
• this Container's foreground color ("foreground")
• this Container's focusability ("focusable")
• this Container's focus traversal keys enabled state ("focusTraversalKeysEnabled")
• this Container's Set of FORWARD_TRAVERSAL_KEYS ("forwardFocusTraversalKeys")
• this Container's Set of BACKWARD_TRAVERSAL_KEYS ("backwardFocusTraversalKeys")
• this Container's Set of UP_CYCLE_TRAVERSAL_KEYS ("upCycleFocusTraversalKeys")
• this Container's Set of DOWN_CYCLE_TRAVERSAL_KEYS ("downCycleFocusTraversalKeys")
• this Container's focus traversal policy ("focusTraversalPolicy")
• this Container's focus-cycle-root state ("focusCycleRoot")
• this Container's focus-traversal-policy-provider state("focusTraversalPolicyProvider")
• this Container's focus-traversal-policy-provider state("focusTraversalPolicyProvider")
Note that if this Container is inheriting a bound property, then no event will be fired in response to a change in the inherited property.

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

  void adjustDecendantsOnParent(int num) 
{
        if (parent != null) {
            parent.adjustDescendants(num);
        }
}

  void adjustDescendants(int num) 
{
        if (num == 0)
            return;
        descendantsCount += num;
        adjustDecendantsOnParent(num);
}

  void adjustListeningChildren(long mask,
    int num) 
{
        if (eventLog.isLoggable(Level.FINE)) {
            boolean toAssert = (mask == AWTEvent.HIERARCHY_EVENT_MASK ||
                                mask == AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK ||
                                mask == (AWTEvent.HIERARCHY_EVENT_MASK |
                                         AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));
            if (!toAssert) {
                eventLog.log(Level.FINE, "Assertion failed");
            }
        }
        if (num == 0)
            return;
        if ((mask & AWTEvent.HIERARCHY_EVENT_MASK) != 0) {
            listeningChildren += num;
        }
        if ((mask & AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK) != 0) {
            listeningBoundsChildren += num;
        }
        adjustListeningChildrenOnParent(mask, num);
}

 public  void applyComponentOrientation(ComponentOrientation o) 
{
        super.applyComponentOrientation(o);
        for (int i = 0 ; i <  ncomponents ; ++i) {
             component[i].applyComponentOrientation(o);
        }
}

Sets the ComponentOrientation property of this container and all components contained within it.

 public boolean areFocusTraversalKeysSet(int id) 
{
        if (id <  0 || id  >= KeyboardFocusManager.TRAVERSAL_KEY_LENGTH) {
            throw new IllegalArgumentException("invalid focus traversal key identifier");
        }
        return (focusTraversalKeys != null && focusTraversalKeys[id] != null);
}

Returns whether the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Container. If this method returns false, this Container is inheriting the Set from an ancestor, or from the current KeyboardFocusManager.

 boolean canContainFocusOwner(Component focusOwnerCandidate) 
{
        if (!(isEnabled() && isDisplayable()
              && isVisible() && isFocusable()))
        {
            return false;
        }
        if (isFocusCycleRoot()) {
            FocusTraversalPolicy policy = getFocusTraversalPolicy();
            if (policy instanceof DefaultFocusTraversalPolicy) {
                if (!((DefaultFocusTraversalPolicy)policy).accept(focusOwnerCandidate)) {
                    return false;
                }
            }
        }
        synchronized(getTreeLock()) {
            if (parent != null) {
                return parent.canContainFocusOwner(focusOwnerCandidate);
            }
        }
        return true;
}

Checks whether this container can contain component which is focus owner. Verifies that container is enable and showing, and if it is focus cycle root its FTP allows component to be focus owner

  void checkGD(String stringID) 
{
        Component tempComp;
        for (int i = 0; i <  component.length; i++) {
            tempComp= component[i];
            if (tempComp != null) {
                tempComp.checkGD(stringID);
            }
        }
}

Checks that all Components that this Container contains are on the same GraphicsDevice as this Container. If not, throws an IllegalArgumentException.

  void clearCurrentFocusCycleRootOnHide() 
{
        KeyboardFocusManager kfm =
            KeyboardFocusManager.getCurrentKeyboardFocusManager();
        Container cont = kfm.getCurrentFocusCycleRoot();
        if (cont == this || isParentOf(cont)) {
            kfm.setGlobalCurrentFocusCycleRoot(null);
        }
}

  void clearMostRecentFocusOwnerOnHide() 
{
        boolean reset = false;
        Window window = null;
        synchronized (getTreeLock()) {
            window = getContainingWindow();
            if (window != null) {
                Component comp = KeyboardFocusManager.getMostRecentFocusOwner(window);
                reset = ((comp == this) || isParentOf(comp));
                // This synchronized should always be the second in a pair
                // (tree lock, KeyboardFocusManager.class)
                synchronized(KeyboardFocusManager.class) {
                    Component storedComp = window.getTemporaryLostComponent();
                    if (isParentOf(storedComp) || storedComp == this) {
                        window.setTemporaryLostComponent(null);
                    }
                }
            }
        }
        if (reset) {
            KeyboardFocusManager.setMostRecentFocusOwner(window, null);
        }
}

 final boolean containsFocus() 
{
        final Component focusOwner = KeyboardFocusManager.
            getCurrentKeyboardFocusManager().getFocusOwner();
        return isParentOf(focusOwner);
}

 public int countComponents() 
{
        return ncomponents;
}

 int countHierarchyMembers() 
{
        if (log.isLoggable(Level.FINE)) {
            // Verify descendantsCount is correct
            int sum = 0;
            for (int i = 0; i <  ncomponents; i++) {
                sum += component[i].countHierarchyMembers();
            }
            if (descendantsCount != sum) {
                log.log(Level.FINE, "Assertion (descendantsCount == sum) failed");
            }
        }
        return descendantsCount + 1;
}

 final  void createChildHierarchyEvents(int id,
    long changeFlags,
    boolean enabledOnToolkit) 
{
        assert Thread.holdsLock(getTreeLock());
        if (ncomponents == 0) {
            return;
        }
        int listeners = getListenersCount(id, enabledOnToolkit);
        for (int count = listeners, i = 0; count  > 0; i++) {
            count -= component[i].createHierarchyEvents(id, this, parent,
                changeFlags, enabledOnToolkit);
        }
}

 final int createHierarchyEvents(int id,
    Component changed,
    Container changedParent,
    long changeFlags,
    boolean enabledOnToolkit) 
{
        assert Thread.holdsLock(getTreeLock());
        int listeners = getListenersCount(id, enabledOnToolkit);
        for (int count = listeners, i = 0; count  > 0; i++) {
            count -= component[i].createHierarchyEvents(id, changed,
                changedParent, changeFlags, enabledOnToolkit);
        }
        return listeners +
            super.createHierarchyEvents(id, changed, changedParent,
                                        changeFlags, enabledOnToolkit);
}

 final  void decreaseComponentCount(Component c) 
{
        synchronized (getTreeLock()) {
            if (!c.isDisplayable()) {
                throw new IllegalStateException(
                    "Peer does not exist while invoking the decreaseComponentCount() method"
                );
            }
            int subHW = 0;
            int subLW = 0;
            if (c instanceof Container) {
                subLW = ((Container)c).numOfLWComponents;
                subHW = ((Container)c).numOfHWComponents;
            }
            if (c.isLightweight()) {
                subLW++;
            } else {
                subHW++;
            }
            for (Container cont = this; cont != null; cont = cont.getContainer()) {
                cont.numOfLWComponents -= subLW;
                cont.numOfHWComponents -= subHW;
            }
        }
}

 public  void deliverEvent(Event e) 
{
        Component comp = getComponentAt(e.x, e.y);
        if ((comp != null) && (comp != this)) {
            e.translate(-comp.x, -comp.y);
            comp.deliverEvent(e);
        } else {
            postEvent(e);
        }
}

  void dispatchEventImpl(AWTEvent e) 
{
        if ((dispatcher != null) && dispatcher.dispatchEvent(e)) {
            // event was sent to a lightweight component.  The
            // native-produced event sent to the native container
            // must be properly disposed of by the peer, so it
            // gets forwarded.  If the native host has been removed
            // as a result of the sending the lightweight event,
            // the peer reference will be null.
            e.consume();
            if (peer != null) {
                peer.handleEvent(e);
            }
            return;
        }
        super.dispatchEventImpl(e);
        synchronized (getTreeLock()) {
            switch (e.getID()) {
              case ComponentEvent.COMPONENT_RESIZED:
                createChildHierarchyEvents(HierarchyEvent.ANCESTOR_RESIZED, 0,
                                           Toolkit.enabledOnToolkit(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));
                break;
              case ComponentEvent.COMPONENT_MOVED:
                createChildHierarchyEvents(HierarchyEvent.ANCESTOR_MOVED, 0,
                                       Toolkit.enabledOnToolkit(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));
                break;
              default:
                break;
            }
        }
}

  void dispatchEventToSelf(AWTEvent e) 
{
        super.dispatchEventImpl(e);
}

 public  void doLayout() 
{
        layout();
}

Causes this container to lay out its components. Most programs should not call this method directly, but should invoke the validate method instead.

 boolean eventEnabled(AWTEvent e) 
{
        int id = e.getID();
        if (id == ContainerEvent.COMPONENT_ADDED ||
            id == ContainerEvent.COMPONENT_REMOVED) {
            if ((eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0 ||
                containerListener != null) {
                return true;
            }
            return false;
        }
        return super.eventEnabled(e);
}

 public Component findComponentAt(Point p) 
{
        return findComponentAt(p.x, p.y);
}

Locates the visible child component that contains the specified point. The top-most child component is returned in the case where there is overlap in the components. If the containing child component is a Container, this method will continue searching for the deepest nested child component. Components which are not visible are ignored during the search.

The findComponentAt method is different from getComponentAt in that getComponentAt only searches the Container's immediate children; if the containing component is a Container, findComponentAt will search that child to find a nested component.

 public Component findComponentAt(int x,
    int y) 
{
        synchronized (getTreeLock()) {
            return findComponentAt(x, y, true);
        }
}

Locates the visible child component that contains the specified position. The top-most child component is returned in the case where there is overlap in the components. If the containing child component is a Container, this method will continue searching for the deepest nested child component. Components which are not visible are ignored during the search.

The findComponentAt method is different from getComponentAt in that getComponentAt only searches the Container's immediate children; if the containing component is a Container, findComponentAt will search that child to find a nested component.

 final Component findComponentAt(int x,
    int y,
    boolean ignoreEnabled) 
{
        if (isRecursivelyVisible()){
            return findComponentAtImpl(x, y, ignoreEnabled);
        }
        return null;
}

Private version of findComponentAt which has a controllable behavior. Setting 'ignoreEnabled' to 'false' bypasses disabled Components during the search. This behavior is used by the lightweight cursor support in sun.awt.GlobalCursorManager. The cursor code calls this function directly via native code. The addition of this feature is temporary, pending the adoption of new, public API which exports this feature.

 final Component findComponentAtImpl(int x,
    int y,
    boolean ignoreEnabled) 
{
        if (!(contains(x, y) && visible && (ignoreEnabled || enabled))) {
            return null;
        }
        int ncomponents = this.ncomponents;
        Component component[] = this.component;
        // Two passes: see comment in sun.awt.SunGraphicsCallback
        for (int i = 0 ; i <  ncomponents ; i++) {
            Component comp = component[i];
            if (comp != null &&
                !(comp.peer instanceof LightweightPeer)) {
                if (comp instanceof Container) {
                    comp = ((Container)comp).findComponentAtImpl(x - comp.x,
                                                             y - comp.y,
                                                             ignoreEnabled);
                } else {
                    comp = comp.locate(x - comp.x, y - comp.y);
                }
                if (comp != null && comp.visible &&
                    (ignoreEnabled || comp.enabled))
                {
                    return comp;
                }
            }
        }
        for (int i = 0 ; i <  ncomponents ; i++) {
            Component comp = component[i];
            if (comp != null &&
                comp.peer instanceof LightweightPeer) {
                if (comp instanceof Container) {
                    comp = ((Container)comp).findComponentAtImpl(x - comp.x,
                                                             y - comp.y,
                                                             ignoreEnabled);
                } else {
                    comp = comp.locate(x - comp.x, y - comp.y);
                }
                if (comp != null && comp.visible &&
                    (ignoreEnabled || comp.enabled))
                {
                    return comp;
                }
            }
        }
        return this;
}

 Accessible getAccessibleAt(Point p) 
{
        synchronized (getTreeLock()) {
            if (this instanceof Accessible) {
                Accessible a = (Accessible)this;
                AccessibleContext ac = a.getAccessibleContext();
                if (ac != null) {
                    AccessibleComponent acmp;
                    Point location;
                    int nchildren = ac.getAccessibleChildrenCount();
                    for (int i=0; i <  nchildren; i++) {
                        a = ac.getAccessibleChild(i);
                        if ((a != null)) {
                            ac = a.getAccessibleContext();
                            if (ac != null) {
                                acmp = ac.getAccessibleComponent();
                                if ((acmp != null) && (acmp.isShowing())) {
                                    location = acmp.getLocation();
                                    Point np = new Point(p.x-location.x,
                                                         p.y-location.y);
                                    if (acmp.contains(np)){
                                        return a;
                                    }
                                }
                            }
                        }
                    }
                }
                return (Accessible)this;
            } else {
                Component ret = this;
                if (!this.contains(p.x,p.y)) {
                    ret = null;
                } else {
                    int ncomponents = this.getComponentCount();
                    for (int i=0; i <  ncomponents; i++) {
                        Component comp = this.getComponent(i);
                        if ((comp != null) && comp.isShowing()) {
                            Point location = comp.getLocation();
                            if (comp.contains(p.x-location.x,p.y-location.y)) {
                                ret = comp;
                            }
                        }
                    }
                }
                if (ret instanceof Accessible) {
                    return (Accessible) ret;
                }
            }
            return null;
        }
}

Returns the Accessible child contained at the local coordinate Point, if one exists. Otherwise returns null.

 Accessible getAccessibleChild(int i) 
{
        synchronized (getTreeLock()) {
            Component[] children = this.getComponents();
            int count = 0;
            for (int j = 0; j <  children.length; j++) {
                if (children[j] instanceof Accessible) {
                    if (count == i) {
                        return (Accessible) children[j];
                    } else {
                        count++;
                    }
                }
            }
            return null;
        }
}

Returns the nth Accessible child of the object.

 int getAccessibleChildrenCount() 
{
        synchronized (getTreeLock()) {
            int count = 0;
            Component[] children = this.getComponents();
            for (int i = 0; i <  children.length; i++) {
                if (children[i] instanceof Accessible) {
                    count++;
                }
            }
            return count;
        }
}

Returns the number of accessible children in the object. If all of the children of this object implement Accessible, then this method should return the number of children of this object.

 public float getAlignmentX() 
{
        float xAlign;
        if (layoutMgr instanceof LayoutManager2) {
            synchronized (getTreeLock()) {
                LayoutManager2 lm = (LayoutManager2) layoutMgr;
                xAlign = lm.getLayoutAlignmentX(this);
            }
        } else {
            xAlign = super.getAlignmentX();
        }
        return xAlign;
}

Returns the alignment along the x axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

 public float getAlignmentY() 
{
        float yAlign;
        if (layoutMgr instanceof LayoutManager2) {
            synchronized (getTreeLock()) {
                LayoutManager2 lm = (LayoutManager2) layoutMgr;
                yAlign = lm.getLayoutAlignmentY(this);
            }
        } else {
            yAlign = super.getAlignmentY();
        }
        return yAlign;
}

Returns the alignment along the y axis. This specifies how the component would like to be aligned relative to other components. The value should be a number between 0 and 1 where 0 represents alignment along the origin, 1 is aligned the furthest away from the origin, 0.5 is centered, etc.

 public Component getComponent(int n) 
{
        synchronized (getTreeLock()) {
            if ((n <  0) || (n  >= ncomponents)) {
                throw new ArrayIndexOutOfBoundsException("No such child: " + n);
            }
            return component[n];
        }
}

Gets the nth component in this container.

 public Component getComponentAt(Point p) 
{
        return getComponentAt(p.x, p.y);
}

Gets the component that contains the specified point.

 public Component getComponentAt(int x,
    int y) 
{
        return locate(x, y);
}

Locates the component that contains the x,y position. The top-most child component is returned in the case where there is overlap in the components. This is determined by finding the component closest to the index 0 that claims to contain the given point via Component.contains(), except that Components which have native peers take precedence over those which do not (i.e., lightweight Components).

 public int getComponentCount() 
{
        return countComponents();
}

Gets the number of components in this panel.

 public int getComponentZOrder(Component comp) 
{
        if (comp == null) {
            return -1;
        }
        synchronized(getTreeLock()) {
            // Quick check - container should be immediate parent of the component
            if (comp.parent != this) {
                return -1;
            }
            for (int i = 0; i <  ncomponents; i++) {
                if (component[i] == comp) {
                    return i;
                }
            }
        }
        // To please javac
        return -1;
}

Returns the z-order index of the component inside the container. The higher a component is in the z-order hierarchy, the lower its index. The component with the lowest z-order index is painted last, above all other child components.

 public Component[] getComponents() 
{
        return getComponents_NoClientCode();
}

Gets all the components in this container.

 final Component[] getComponents_NoClientCode() 
{
        synchronized (getTreeLock()) {
            return Arrays.copyOf(component, ncomponents);
        }
}

 public synchronized ContainerListener[] getContainerListeners() 
{
        return (ContainerListener[]) (getListeners(ContainerListener.class));
}

Returns an array of all the container listeners registered on this container.

 Component getDropTargetEventTarget(int x,
    int y,
    boolean includeSelf) 
{
        return getMouseEventTarget(x, y, includeSelf,
                                   DropTargetEventTargetFilter.FILTER,
                                   SEARCH_HEAVYWEIGHTS);
}

Fetches the top-most (deepest) component to receive SunDropTargetEvents.

 public Set getFocusTraversalKeys(int id) 
{
        if (id <  0 || id  >= KeyboardFocusManager.TRAVERSAL_KEY_LENGTH) {
            throw new IllegalArgumentException("invalid focus traversal key identifier");
        }
        // Don't call super.getFocusTraversalKey. The Component parameter check
        // does not allow DOWN_CYCLE_TRAVERSAL_KEY, but we do.
        return getFocusTraversalKeys_NoIDCheck(id);
}

Returns the Set of focus traversal keys for a given traversal operation for this Container. (See setFocusTraversalKeys for a full description of each key.)

If a Set of traversal keys has not been explicitly defined for this Container, then this Container's parent's Set is returned. If no Set has been explicitly defined for any of this Container's ancestors, then the current KeyboardFocusManager's default Set is returned.

 public FocusTraversalPolicy getFocusTraversalPolicy() 
{
        if (!isFocusTraversalPolicyProvider() && !isFocusCycleRoot()) {
            return null;
        }
        FocusTraversalPolicy policy = this.focusTraversalPolicy;
        if (policy != null) {
            return policy;
        }
        Container rootAncestor = getFocusCycleRootAncestor();
        if (rootAncestor != null) {
            return rootAncestor.getFocusTraversalPolicy();
        } else {
            return KeyboardFocusManager.getCurrentKeyboardFocusManager().
                getDefaultFocusTraversalPolicy();
        }
}

Returns the focus traversal policy that will manage keyboard traversal of this Container's children, or null if this Container is not a focus cycle root. If no traversal policy has been explicitly set for this Container, then this Container's focus-cycle-root ancestor's policy is returned.

 Container getHeavyweightContainer() 
{
        checkTreeLock();
        if (peer != null && !(peer instanceof LightweightPeer)) {
            return this;
        } else {
            return getNativeContainer();
        }
}

Returns closest heavyweight component to this container. If this container is heavyweight returns this.

 public Insets getInsets() 
{
        return insets();
}

Determines the insets of this container, which indicate the size of the container's border.

A Frame object, for example, has a top inset that corresponds to the height of the frame's title bar.

 public LayoutManager getLayout() 
{
        return layoutMgr;
}

Gets the layout manager for this container.

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

Returns an array of all the objects currently registered as FooListeners upon this Container. 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 Container c for its container listeners with the following code:

ContainerListener[] cls = (ContainerListener[])(c.getListeners(ContainerListener.class));

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

 public Dimension getMaximumSize() 
{
        /* Avoid grabbing the lock if a reasonable cached size value
         * is available.
         */
        Dimension dim = maxSize;
        if (dim == null || !(isMaximumSizeSet() || isValid())) {
            synchronized (getTreeLock()) {
               if (layoutMgr instanceof LayoutManager2) {
                    LayoutManager2 lm = (LayoutManager2) layoutMgr;
                    maxSize = lm.maximumLayoutSize(this);
               } else {
                    maxSize = super.getMaximumSize();
               }
               dim = maxSize;
            }
        }
        if (dim != null){
            return new Dimension(dim);
        }
        else{
            return dim;
        }
}

Returns the maximum size of this container. If the maximum size has not been set explicitly by Component#setMaximumSize(Dimension) and the LayoutManager installed on this {@code Container} is an instance of LayoutManager2 , then LayoutManager2#maximumLayoutSize(Container) is used to calculate the maximum size.

Note: some implementations may cache the value returned from the {@code LayoutManager2}. Implementations that cache need not invoke {@code maximumLayoutSize} on the {@code LayoutManager2} every time this method is invoked, rather the {@code LayoutManager2} will only be queried after the {@code Container} becomes invalid.

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

Returns the minimum size of this container. If the minimum size has not been set explicitly by Component#setMinimumSize(Dimension) and this {@code Container} has a {@code non-null} LayoutManager , then LayoutManager#minimumLayoutSize(Container) is used to calculate the minimum size.

Note: some implementations may cache the value returned from the {@code LayoutManager}. Implementations that cache need not invoke {@code minimumLayoutSize} on the {@code LayoutManager} every time this method is invoked, rather the {@code LayoutManager} will only be queried after the {@code Container} becomes invalid.

 Component getMouseEventTarget(int x,
    int y,
    boolean includeSelf) 
{
        return getMouseEventTarget(x, y, includeSelf,
                                   MouseEventTargetFilter.FILTER,
                                   !SEARCH_HEAVYWEIGHTS);
}

Fetchs the top-most (deepest) lightweight component that is interested in receiving mouse events.

 public Point getMousePosition(boolean allowChildren) throws HeadlessException 
{
        if (GraphicsEnvironment.isHeadless()) {
            throw new HeadlessException();
        }
        PointerInfo pi = (PointerInfo)java.security.AccessController.doPrivileged(
            new java.security.PrivilegedAction() {
                public Object run() {
                    return MouseInfo.getPointerInfo();
                }
            }
        );
        synchronized (getTreeLock()) {
            Component inTheSameWindow = findUnderMouseInWindow(pi);
            if (isSameOrAncestorOf(inTheSameWindow, allowChildren)) {
                return  pointRelativeToComponent(pi.getLocation());
            }
            return null;
        }
}

Returns the position of the mouse pointer in this Container's coordinate space if the Container is under the mouse pointer, otherwise returns null. This method is similar to Component#getMousePosition() with the exception that it can take the Container's children into account. If allowChildren is false, this method will return a non-null value only if the mouse pointer is above the Container directly, not above the part obscured by children. If allowChildren is true, this method returns a non-null value if the mouse pointer is above Container or any of its descendants.

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

Returns the preferred size of this container. If the preferred size has not been set explicitly by Component#setPreferredSize(Dimension) and this {@code Container} has a {@code non-null} LayoutManager , then LayoutManager#preferredLayoutSize(Container) is used to calculate the preferred size.

Note: some implementations may cache the value returned from the {@code LayoutManager}. Implementations that cache need not invoke {@code preferredLayoutSize} on the {@code LayoutManager} every time this method is invoked, rather the {@code LayoutManager} will only be queried after the {@code Container} becomes invalid.

 final Container getTraversalRoot() 
{
        if (isFocusCycleRoot()) {
            return findTraversalRoot();
        }
        return super.getTraversalRoot();
}

 final  void increaseComponentCount(Component c) 
{
        synchronized (getTreeLock()) {
            if (!c.isDisplayable()) {
                throw new IllegalStateException(
                    "Peer does not exist while invoking the increaseComponentCount() method"
                );
            }
            int addHW = 0;
            int addLW = 0;
            if (c instanceof Container) {
                addLW = ((Container)c).numOfLWComponents;
                addHW = ((Container)c).numOfHWComponents;
            }
            if (c.isLightweight()) {
                addLW++;
            } else {
                addHW++;
            }
            for (Container cont = this; cont != null; cont = cont.getContainer()) {
                cont.numOfLWComponents += addLW;
                cont.numOfHWComponents += addHW;
            }
        }
}

  void initializeFocusTraversalKeys() 
{
        focusTraversalKeys = new Set[4];
}

 public Insets insets() 
{
        ComponentPeer peer = this.peer;
        if (peer instanceof ContainerPeer) {
            ContainerPeer cpeer = (ContainerPeer)peer;
            return (Insets)cpeer.insets().clone();
        }
        return new Insets(0, 0, 0, 0);
}

 public  void invalidate() 
{
        LayoutManager layoutMgr = this.layoutMgr;
        if (layoutMgr instanceof LayoutManager2) {
            LayoutManager2 lm = (LayoutManager2) layoutMgr;
            lm.invalidateLayout(this);
        }
        super.invalidate();
}

Invalidates the container. The container and all parents above it are marked as needing to be laid out. This method can be called often, so it needs to execute quickly.

If the {@code LayoutManager} installed on this container is an instance of {@code LayoutManager2}, then LayoutManager2#invalidateLayout(Container) is invoked on it supplying this {@code Container} as the argument.

  void invalidateTree() 
{
        synchronized (getTreeLock()) {
            for (int i = 0; i <  ncomponents; ++i) {
                Component comp = component[i];
                if (comp instanceof Container) {
                    ((Container)comp).invalidateTree();
                }
                else {
                    if (comp.valid) {
                        comp.invalidate();
                    }
                }
            }
            if (valid) {
                invalidate();
            }
        }
}

Recursively descends the container tree and invalidates all contained components.

 public boolean isAncestorOf(Component c) 
{
        Container p;
        if (c == null || ((p = c.getParent()) == null)) {
            return false;
        }
        while (p != null) {
            if (p == this) {
                return true;
            }
            p = p.getParent();
        }
        return false;
}

Checks if the component is contained in the component hierarchy of this container.

 public boolean isFocusCycleRoot() 
{
        return focusCycleRoot;
}

Returns whether this Container is the root of a focus traversal cycle. Once focus enters a traversal cycle, typically it cannot leave it via focus traversal unless one of the up- or down-cycle keys is pressed. Normal traversal is limited to this Container, and all of this Container's descendants that are not descendants of inferior focus cycle roots. Note that a FocusTraversalPolicy may bend these restrictions, however. For example, ContainerOrderFocusTraversalPolicy supports implicit down-cycle traversal.

 public boolean isFocusCycleRoot(Container container) 
{
        if (isFocusCycleRoot() && container == this) {
            return true;
        } else {
            return super.isFocusCycleRoot(container);
        }
}

Returns whether the specified Container is the focus cycle root of this Container's focus traversal cycle. Each focus traversal cycle has only a single focus cycle root and each Container which is not a focus cycle root belongs to only a single focus traversal cycle. Containers which are focus cycle roots belong to two cycles: one rooted at the Container itself, and one rooted at the Container's nearest focus-cycle-root ancestor. This method will return true for both such Containers in this case.

 public final boolean isFocusTraversalPolicyProvider() 
{
        return focusTraversalPolicyProvider;
}

Returns whether this container provides focus traversal policy. If this property is set to true then when keyboard focus manager searches container hierarchy for focus traversal policy and encounters this container before any other container with this property as true or focus cycle roots then its focus traversal policy will be used instead of focus cycle root's policy.

 public boolean isFocusTraversalPolicySet() 
{
        return (focusTraversalPolicy != null);
}

Returns whether the focus traversal policy has been explicitly set for this Container. If this method returns false, this Container will inherit its focus traversal policy from an ancestor.

 boolean isSameOrAncestorOf(Component comp,
    boolean allowChildren) 
{
        return this == comp || (allowChildren && isParentOf(comp));
}

 public  void layout() 
{
        LayoutManager layoutMgr = this.layoutMgr;
        if (layoutMgr != null) {
            layoutMgr.layoutContainer(this);
        }
}

  void lightweightPaint(Graphics g) 
{
        super.lightweightPaint(g);
        paintHeavyweightComponents(g);
}

Simulates the peer callbacks into java.awt for printing of lightweight Containers.

  void lightweightPrint(Graphics g) 
{
        super.lightweightPrint(g);
        printHeavyweightComponents(g);
}

Simulates the peer callbacks into java.awt for printing of lightweight Containers.

 public  void list(PrintStream out,
    int indent) 
{
        super.list(out, indent);
        int ncomponents = this.ncomponents;
        Component component[] = this.component;
        for (int i = 0 ; i <  ncomponents ; i++) {
            Component comp = component[i];
            if (comp != null) {
                comp.list(out, indent+1);
            }
        }
}

Prints a listing of this container to the specified output stream. The listing starts at the specified indentation.

The immediate children of the container are printed with an indentation of indent+1. The children of those children are printed at indent+2 and so on.

 public  void list(PrintWriter out,
    int indent) 
{
        super.list(out, indent);
        int ncomponents = this.ncomponents;
        Component component[] = this.component;
        for (int i = 0 ; i <  ncomponents ; i++) {
            Component comp = component[i];
            if (comp != null) {
                comp.list(out, indent+1);
            }
        }
}

Prints out a list, starting at the specified indentation, to the specified print writer.

The immediate children of the container are printed with an indentation of indent+1. The children of those children are printed at indent+2 and so on.

 public Component locate(int x,
    int y) 
{
        if (!contains(x, y)) {
            return null;
        }
        synchronized (getTreeLock()) {
            // Two passes: see comment in sun.awt.SunGraphicsCallback
            for (int i = 0 ; i <  ncomponents ; i++) {
                Component comp = component[i];
                if (comp != null &&
                    !(comp.peer instanceof LightweightPeer)) {
                    if (comp.contains(x - comp.x, y - comp.y)) {
                        return comp;
                    }
                }
            }
            for (int i = 0 ; i <  ncomponents ; i++) {
                Component comp = component[i];
                if (comp != null &&
                    comp.peer instanceof LightweightPeer) {
                    if (comp.contains(x - comp.x, y - comp.y)) {
                        return comp;
                    }
                }
            }
        }
        return this;
}

 public Dimension minimumSize() 
{
        /* Avoid grabbing the lock if a reasonable cached size value
         * is available.
         */
        Dimension dim = minSize;
        if (dim == null || !(isMinimumSizeSet() || isValid())) {
            synchronized (getTreeLock()) {
                minSize = (layoutMgr != null) ?
                    layoutMgr.minimumLayoutSize(this) :
                    super.minimumSize();
                dim = minSize;
            }
        }
        if (dim != null){
            return new Dimension(dim);
        }
        else{
            return dim;
        }
}

  void mixOnHiding(boolean isLightweight) 
{
        synchronized (getTreeLock()) {
            if (mixingLog.isLoggable(Level.FINE)) {
                mixingLog.fine("this = " + this +
                        "; isLightweight=" + isLightweight);
            }
            if (isLightweight) {
                recursiveHideHeavyweightChildren();
            }
            super.mixOnHiding(isLightweight);
        }
}

  void mixOnReshaping() 
{
        synchronized (getTreeLock()) {
            if (mixingLog.isLoggable(Level.FINE)) {
                mixingLog.fine("this = " + this);
            }
            if (isLightweight() && hasHeavyweightDescendants()) {
                final Point origin = new Point(getX(), getY());
                for (Container cont = getContainer();
                        cont != null && cont.isLightweight();
                        cont = cont.getContainer())
                {
                    origin.translate(cont.getX(), cont.getY());
                }
                recursiveRelocateHeavyweightChildren(origin);
            }
            super.mixOnReshaping();
        }
}

  void mixOnShowing() 
{
        synchronized (getTreeLock()) {
            if (mixingLog.isLoggable(Level.FINE)) {
                mixingLog.fine("this = " + this);
            }
            boolean isLightweight = isLightweight();
            if (isLightweight && isRecursivelyVisibleUpToHeavyweightContainer()) {
                recursiveShowHeavyweightChildren();
            }
            if (!isLightweight || (isLightweight && hasHeavyweightDescendants())) {
                recursiveApplyCurrentShape();
            }
            super.mixOnShowing();
        }
}

  void mixOnZOrderChanging(int oldZorder,
    int newZorder) 
{
        synchronized (getTreeLock()) {
            if (mixingLog.isLoggable(Level.FINE)) {
                mixingLog.fine("this = " + this +
                    "; oldZ=" + oldZorder + "; newZ=" + newZorder);
            }
            boolean becameHigher = newZorder <  oldZorder;
            if (becameHigher && isLightweight() && hasHeavyweightDescendants()) {
                recursiveApplyCurrentShape();
            }
            super.mixOnZOrderChanging(oldZorder, newZorder);
        }
}

 int numListening(long mask) 
{
        int superListening = super.numListening(mask);
        if (mask == AWTEvent.HIERARCHY_EVENT_MASK) {
            if (eventLog.isLoggable(Level.FINE)) {
                // Verify listeningChildren is correct
                int sum = 0;
                for (int i = 0; i <  ncomponents; i++) {
                    sum += component[i].numListening(mask);
                }
                if (listeningChildren != sum) {
                    eventLog.log(Level.FINE, "Assertion (listeningChildren == sum) failed");
                }
            }
            return listeningChildren + superListening;
        } else if (mask == AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK) {
            if (eventLog.isLoggable(Level.FINE)) {
                // Verify listeningBoundsChildren is correct
                int sum = 0;
                for (int i = 0; i <  ncomponents; i++) {
                    sum += component[i].numListening(mask);
                }
                if (listeningBoundsChildren != sum) {
                    eventLog.log(Level.FINE, "Assertion (listeningBoundsChildren == sum) failed");
                }
            }
            return listeningBoundsChildren + superListening;
        } else {
            // assert false;
            if (eventLog.isLoggable(Level.FINE)) {
                eventLog.log(Level.FINE, "This code must never be reached");
            }
            return superListening;
        }
}

 public  void paint(Graphics g) 
{
        if (isShowing()) {
            synchronized (this) {
                if (printing) {
                    if (printingThreads.contains(Thread.currentThread())) {
                        return;
                    }
                }
            }
            // The container is showing on screen and
            // this paint() is not called from print().
            // Paint self and forward the paint to lightweight subcomponents.
            // super.paint(); -- Don't bother, since it's a NOP.
            GraphicsCallback.PaintCallback.getInstance().
                runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS);
        }
}

Paints the container. This forwards the paint to any lightweight components that are children of this container. If this method is reimplemented, super.paint(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, paint() will not be forwarded to that child.

 public  void paintComponents(Graphics g) 
{
        if (isShowing()) {
            GraphicsCallback.PaintAllCallback.getInstance().
                runComponents(component, g, GraphicsCallback.TWO_PASSES);
        }
}

Paints each of the components in this container.

  void paintHeavyweightComponents(Graphics g) 
{
        if (isShowing()) {
            GraphicsCallback.PaintHeavyweightComponentsCallback.getInstance().
                runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS |
                                            GraphicsCallback.HEAVYWEIGHTS);
        }
}

Prints all the heavyweight subcomponents.

 protected String paramString() 
{
        String str = super.paramString();
        LayoutManager layoutMgr = this.layoutMgr;
        if (layoutMgr != null) {
            str += ",layout=" + layoutMgr.getClass().getName();
        }
        return str;
}

Returns a string representing the state of this Container. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null.

  void postProcessKeyEvent(KeyEvent e) 
{
        Container parent = this.parent;
        if (parent != null) {
            parent.postProcessKeyEvent(e);
        }
}

 boolean postsOldMouseEvents() 
{
        return true;
}

  void preProcessKeyEvent(KeyEvent e) 
{
        Container parent = this.parent;
        if (parent != null) {
            parent.preProcessKeyEvent(e);
        }
}

 public Dimension preferredSize() 
{
        /* Avoid grabbing the lock if a reasonable cached size value
         * is available.
         */
        Dimension dim = prefSize;
        if (dim == null || !(isPreferredSizeSet() || isValid())) {
            synchronized (getTreeLock()) {
                prefSize = (layoutMgr != null) ?
                    layoutMgr.preferredLayoutSize(this) :
                    super.preferredSize();
                dim = prefSize;
            }
        }
        if (dim != null){
            return new Dimension(dim);
        }
        else{
            return dim;
        }
}

 public  void print(Graphics g) 
{
        if (isShowing()) {
            Thread t = Thread.currentThread();
            try {
                synchronized (this) {
                    if (printingThreads == null) {
                        printingThreads = new HashSet();
                    }
                    printingThreads.add(t);
                    printing = true;
                }
                super.print(g);  // By default, Component.print() calls paint()
            } finally {
                synchronized (this) {
                    printingThreads.remove(t);
                    printing = !printingThreads.isEmpty();
                }
            }
            GraphicsCallback.PrintCallback.getInstance().
                runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS);
        }
}

Prints the container. This forwards the print to any lightweight components that are children of this container. If this method is reimplemented, super.print(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, print() will not be forwarded to that child.

 public  void printComponents(Graphics g) 
{
        if (isShowing()) {
            GraphicsCallback.PrintAllCallback.getInstance().
                runComponents(component, g, GraphicsCallback.TWO_PASSES);
        }
}

Prints each of the components in this container.

  void printHeavyweightComponents(Graphics g) 
{
        if (isShowing()) {
            GraphicsCallback.PrintHeavyweightComponentsCallback.getInstance().
                runComponents(component, g, GraphicsCallback.LIGHTWEIGHTS |
                                            GraphicsCallback.HEAVYWEIGHTS);
        }
}

Prints all the heavyweight subcomponents.

 protected  void processContainerEvent(ContainerEvent e) 
{
        ContainerListener listener = containerListener;
        if (listener != null) {
            switch(e.getID()) {
              case ContainerEvent.COMPONENT_ADDED:
                listener.componentAdded(e);
                break;
              case ContainerEvent.COMPONENT_REMOVED:
                listener.componentRemoved(e);
                break;
            }
        }
}

Processes container events occurring on this container by dispatching them to any registered ContainerListener objects. NOTE: This method will not be called unless container events are enabled for this component; this happens when one of the following occurs:
• A ContainerListener object is registered via addContainerListener
• Container 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 ContainerEvent) {
            processContainerEvent((ContainerEvent)e);
            return;
        }
        super.processEvent(e);
}

Processes events on this container. If the event is a ContainerEvent, it invokes the processContainerEvent method, else it invokes its superclass's processEvent.

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

  void proxyEnableEvents(long events) 
{
        if (peer instanceof LightweightPeer) {
            // this container is lightweight.... continue sending it
            // upward.
            if (parent != null) {
                parent.proxyEnableEvents(events);
            }
        } else {
            // This is a native container, so it needs to host
            // one of it's children.  If this function is called before
            // a peer has been created we don't yet have a dispatcher
            // because it has not yet been determined if this instance
            // is lightweight.
            if (dispatcher != null) {
                dispatcher.enableEvents(events);
            }
        }
}

This is called by lightweight components that want the containing windowed parent to enable some kind of events on their behalf. This is needed for events that are normally only dispatched to windows to be accepted so that they can be forwarded downward to the lightweight component that has enabled them.

 final  void recursiveApplyCurrentShape() 
{
        recursiveApplyCurrentShape(getTopmostComponentIndex(), getBottommostComponentIndex());
}

 final  void recursiveApplyCurrentShape(int fromZorder) 
{
        recursiveApplyCurrentShape(fromZorder, getBottommostComponentIndex());
}

 final  void recursiveApplyCurrentShape(int fromZorder,
    int toZorder) 
{
        checkTreeLock();
        if (mixingLog.isLoggable(Level.FINE)) {
            mixingLog.fine("this = " + this +
                "; fromZ=" + fromZorder + "; toZ=" + toZorder);
        }
        if (fromZorder == -1) {
            return;
        }
        for (int index = fromZorder; index < = toZorder; index++) {
            Component comp = getComponent(index);
            if (!comp.isLightweight()) {
                comp.applyCurrentShape();
            } else if (comp instanceof Container &&
                    ((Container)comp).hasHeavyweightDescendants()) {
                ((Container)comp).recursiveApplyCurrentShape();
            }
        }
}

 final  void recursiveSubtractAndApplyShape(Region shape) 
{
        recursiveSubtractAndApplyShape(shape, getTopmostComponentIndex(), getBottommostComponentIndex());
}

 final  void recursiveSubtractAndApplyShape(Region shape,
    int fromZorder) 
{
        recursiveSubtractAndApplyShape(shape, fromZorder, getBottommostComponentIndex());
}

 final  void recursiveSubtractAndApplyShape(Region shape,
    int fromZorder,
    int toZorder) 
{
        checkTreeLock();
        if (mixingLog.isLoggable(Level.FINE)) {
            mixingLog.fine("this = " + this +
                "; shape=" + shape + "; fromZ=" + fromZorder + "; toZ=" + toZorder);
        }
        if (fromZorder == -1) {
            return;
        }
        for (int index = fromZorder; index < = toZorder; index++) {
            Component comp = getComponent(index);
            if (!comp.isLightweight()) {
                comp.subtractAndApplyShape(shape);
            } else if (comp instanceof Container &&
                    ((Container)comp).hasHeavyweightDescendants() && comp.isShowing()) {
                ((Container)comp).recursiveSubtractAndApplyShape(shape);
            }
        }
}

 public  void remove(int index) 
{
        synchronized (getTreeLock()) {
            if (index <  0  || index  >= ncomponents) {
                throw new ArrayIndexOutOfBoundsException(index);
            }
            Component comp = component[index];
            if (peer != null) {
                comp.removeNotify();
            }
            if (layoutMgr != null) {
                layoutMgr.removeLayoutComponent(comp);
            }
            adjustListeningChildren(AWTEvent.HIERARCHY_EVENT_MASK,
                -comp.numListening(AWTEvent.HIERARCHY_EVENT_MASK));
            adjustListeningChildren(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK,
                -comp.numListening(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK));
            adjustDescendants(-(comp.countHierarchyMembers()));
            comp.parent = null;
            System.arraycopy(component, index + 1,
                             component, index,
                             ncomponents - index - 1);
            component[--ncomponents] = null;
            if (valid) {
                invalidate();
            }
            if (containerListener != null ||
                (eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0 ||
                Toolkit.enabledOnToolkit(AWTEvent.CONTAINER_EVENT_MASK)) {
                ContainerEvent e = new ContainerEvent(this,
                                     ContainerEvent.COMPONENT_REMOVED,
                                     comp);
                dispatchEvent(e);
            }
            comp.createHierarchyEvents(HierarchyEvent.HIERARCHY_CHANGED, comp,
                                       this, HierarchyEvent.PARENT_CHANGED,
                                       Toolkit.enabledOnToolkit(AWTEvent.HIERARCHY_EVENT_MASK));
            if (peer != null && layoutMgr == null && isVisible()) {
                updateCursorImmediately();
            }
        }
}

Removes the component, specified by index, from this container. This method also notifies the layout manager to remove the component from this container's layout via the removeLayoutComponent method.

Note: If a component has been removed from a container that had been displayed, #validate must be called on that container to reflect changes. If multiple components are being removed, you can improve efficiency by calling #validate only once, after all the components have been removed.

 public  void remove(Component comp) 
{
        synchronized (getTreeLock()) {
            if (comp.parent == this)  {
                /* Search backwards, expect that more recent additions
                 * are more likely to be removed.
                 */
                Component component[] = this.component;
                for (int i = ncomponents; --i  >= 0; ) {
                    if (component[i] == comp) {
                        remove(i);
                    }
                }
            }
        }
}

Removes the specified component from this container. This method also notifies the layout manager to remove the component from this container's layout via the removeLayoutComponent method.

Note: If a component has been removed from a container that had been displayed, #validate must be called on that container to reflect changes. If multiple components are being removed, you can improve efficiency by calling #validate only once, after all the components have been removed.

 public  void removeAll() 
{
        synchronized (getTreeLock()) {
            adjustListeningChildren(AWTEvent.HIERARCHY_EVENT_MASK,
                                    -listeningChildren);
            adjustListeningChildren(AWTEvent.HIERARCHY_BOUNDS_EVENT_MASK,
                                    -listeningBoundsChildren);
            adjustDescendants(-descendantsCount);
            while (ncomponents  > 0) {
                Component comp = component[--ncomponents];
                component[ncomponents] = null;
                if (peer != null) {
                    comp.removeNotify();
                }
                if (layoutMgr != null) {
                    layoutMgr.removeLayoutComponent(comp);
                }
                comp.parent = null;
                if (containerListener != null ||
                   (eventMask & AWTEvent.CONTAINER_EVENT_MASK) != 0 ||
                    Toolkit.enabledOnToolkit(AWTEvent.CONTAINER_EVENT_MASK)) {
                    ContainerEvent e = new ContainerEvent(this,
                                     ContainerEvent.COMPONENT_REMOVED,
                                     comp);
                    dispatchEvent(e);
                }
                comp.createHierarchyEvents(HierarchyEvent.HIERARCHY_CHANGED,
                                           comp, this,
                                           HierarchyEvent.PARENT_CHANGED,
                                           Toolkit.enabledOnToolkit(AWTEvent.HIERARCHY_EVENT_MASK));
            }
            if (peer != null && layoutMgr == null && isVisible()) {
                updateCursorImmediately();
            }
            if (valid) {
                invalidate();
            }
        }
}

Removes all the components from this container. This method also notifies the layout manager to remove the components from this container's layout via the removeLayoutComponent method.

 public synchronized  void removeContainerListener(ContainerListener l) 
{
        if (l == null) {
            return;
        }
        containerListener = AWTEventMulticaster.remove(containerListener, l);
}

Removes the specified container listener so it no longer receives container events from this container. If 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()) {
            int ncomponents = this.ncomponents;
            Component component[] = this.component;
            for (int i = ncomponents - 1; i  >= 0; i--) {
                if( component[i] != null ) {
                    // Fix for 6607170.
                    // We want to suppress focus change on disposal
                    // of the focused component. But because of focus
                    // is asynchronous, we should suppress focus change
                    // on every component in case it receives native focus
                    // in the process of disposal.
                    component[i].setAutoFocusTransferOnDisposal(false);
                    component[i].removeNotify();
                    component[i].setAutoFocusTransferOnDisposal(true);
                }
            }
            // If some of the children had focus before disposal then it still has.
            // Auto-transfer focus to the next (or previous) component if auto-transfer
            // is enabled.
            if (containsFocus() && KeyboardFocusManager.isAutoFocusTransferEnabledFor(this)) {
                if (!transferFocus(false)) {
                    transferFocusBackward(true);
                }
            }
            if ( dispatcher != null ) {
                dispatcher.dispose();
        dispatcher = null;
            }
            super.removeNotify();
        }
}

Makes this Container undisplayable by removing its connection to its native screen resource. Making a container undisplayable will cause all of its children to be made undisplayable. This method is called by the toolkit internally and should not be called directly by programs.

 public  void setComponentZOrder(Component comp,
    int index) 
{
         synchronized (getTreeLock()) {
             // Store parent because remove will clear it
             Container curParent = comp.parent;
             int oldZindex = getComponentZOrder(comp);
             if (curParent == this && index == oldZindex) {
                 return;
             }
             checkAdding(comp, index);
             boolean peerRecreated = (curParent != null) ?
                 curParent.removeDelicately(comp, this, index) : false;
             addDelicately(comp, curParent, index);
             // If the oldZindex == -1, the component gets inserted,
             // rather than it changes its z-order.
             if (!peerRecreated && oldZindex != -1) {
                 // The new 'index' cannot be == -1.
                 // It gets checked at the checkAdding() method.
                 // Therefore both oldZIndex and index denote
                 // some existing positions at this point and
                 // this is actually a Z-order changing.
                 comp.mixOnZOrderChanging(oldZindex, index);
             }
         }
}

Moves the specified component to the specified z-order index in the container. The z-order determines the order that components are painted; the component with the highest z-order paints first and the component with the lowest z-order paints last. Where components overlap, the component with the lower z-order paints over the component with the higher z-order.

If the component is a child of some other container, it is removed from that container before being added to this container. The important difference between this method and java.awt.Container.add(Component, int) is that this method doesn't call removeNotify on the component while removing it from its previous container unless necessary and when allowed by the underlying native windowing system. This way, if the component has the keyboard focus, it maintains the focus when moved to the new position.

This property is guaranteed to apply only to lightweight non-Container components.

Note: Not all platforms support changing the z-order of heavyweight components from one container into another without the call to removeNotify. There is no way to detect whether a platform supports this, so developers shouldn't make any assumptions.

 public  void setFocusCycleRoot(boolean focusCycleRoot) 
{
        boolean oldFocusCycleRoot;
        synchronized (this) {
            oldFocusCycleRoot = this.focusCycleRoot;
            this.focusCycleRoot = focusCycleRoot;
        }
        firePropertyChange("focusCycleRoot", oldFocusCycleRoot,
                           focusCycleRoot);
}

Sets whether this Container is the root of a focus traversal cycle. Once focus enters a traversal cycle, typically it cannot leave it via focus traversal unless one of the up- or down-cycle keys is pressed. Normal traversal is limited to this Container, and all of this Container's descendants that are not descendants of inferior focus cycle roots. Note that a FocusTraversalPolicy may bend these restrictions, however. For example, ContainerOrderFocusTraversalPolicy supports implicit down-cycle traversal.

The alternative way to specify the traversal order of this Container's children is to make this Container a focus traversal policy provider.

 public  void setFocusTraversalKeys(int id,
    Set keystrokes) 
{
        if (id <  0 || id  >= KeyboardFocusManager.TRAVERSAL_KEY_LENGTH) {
            throw new IllegalArgumentException("invalid focus traversal key identifier");
        }
        // Don't call super.setFocusTraversalKey. The Component parameter check
        // does not allow DOWN_CYCLE_TRAVERSAL_KEYS, but we do.
        setFocusTraversalKeys_NoIDCheck(id, keystrokes);
}

Sets the focus traversal keys for a given traversal operation for this Container.

The default values for a Container's focus traversal keys are implementation-dependent. Sun recommends that all implementations for a particular native platform use the same default values. The recommendations for Windows and Unix are listed below. These recommendations are used in the Sun AWT implementations.

Identifier	Meaning	Default
KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS	Normal forward keyboard traversal	TAB on KEY_PRESSED, CTRL-TAB on KEY_PRESSED
KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS	Normal reverse keyboard traversal	SHIFT-TAB on KEY_PRESSED, CTRL-SHIFT-TAB on KEY_PRESSED
KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS	Go up one focus traversal cycle	none
KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS		Go down one focus traversal cycle	none

To disable a traversal key, use an empty Set; Collections.EMPTY_SET is recommended.

Using the AWTKeyStroke API, client code can specify on which of two specific KeyEvents, KEY_PRESSED or KEY_RELEASED, the focus traversal operation will occur. Regardless of which KeyEvent is specified, however, all KeyEvents related to the focus traversal key, including the associated KEY_TYPED event, will be consumed, and will not be dispatched to any Container. It is a runtime error to specify a KEY_TYPED event as mapping to a focus traversal operation, or to map the same event to multiple default focus traversal operations.

If a value of null is specified for the Set, this Container inherits the Set from its parent. If all ancestors of this Container have null specified for the Set, then the current KeyboardFocusManager's default Set is used.

 public  void setFocusTraversalPolicy(FocusTraversalPolicy policy) 
{
        FocusTraversalPolicy oldPolicy;
        synchronized (this) {
            oldPolicy = this.focusTraversalPolicy;
            this.focusTraversalPolicy = policy;
        }
        firePropertyChange("focusTraversalPolicy", oldPolicy, policy);
}

Sets the focus traversal policy that will manage keyboard traversal of this Container's children, if this Container is a focus cycle root. If the argument is null, this Container inherits its policy from its focus- cycle-root ancestor. If the argument is non-null, this policy will be inherited by all focus-cycle-root children that have no keyboard- traversal policy of their own (as will, recursively, their focus-cycle- root children).

If this Container is not a focus cycle root, the policy will be remembered, but will not be used or inherited by this or any other Containers until this Container is made a focus cycle root.

 public final  void setFocusTraversalPolicyProvider(boolean provider) 
{
        boolean oldProvider;
        synchronized(this) {
            oldProvider = focusTraversalPolicyProvider;
            focusTraversalPolicyProvider = provider;
        }
        firePropertyChange("focusTraversalPolicyProvider", oldProvider, provider);
}

Sets whether this container will be used to provide focus traversal policy. Container with this property as true will be used to acquire focus traversal policy instead of closest focus cycle root ancestor.

 public  void setFont(Font f) 
{
        boolean shouldinvalidate = false;
        Font oldfont = getFont();
        super.setFont(f);
        Font newfont = getFont();
        if (newfont != oldfont && (oldfont == null ||
                                   !oldfont.equals(newfont))) {
            invalidateTree();
        }
}

Sets the font of this container.

 public  void setLayout(LayoutManager mgr) 
{
        layoutMgr = mgr;
        if (valid) {
            invalidate();
        }
}

Sets the layout manager for this container.

 public  void transferFocusDownCycle() 
{
        if (isFocusCycleRoot()) {
            KeyboardFocusManager.getCurrentKeyboardFocusManager().
                setGlobalCurrentFocusCycleRoot(this);
            Component toFocus = getFocusTraversalPolicy().
                getDefaultComponent(this);
            if (toFocus != null) {
                toFocus.requestFocus(CausedFocusEvent.Cause.TRAVERSAL_DOWN);
            }
        }
}

Transfers the focus down one focus traversal cycle. If this Container is a focus cycle root, then the focus owner is set to this Container's default Component to focus, and the current focus cycle root is set to this Container. If this Container is not a focus cycle root, then no focus traversal operation occurs.

 public  void update(Graphics g) 
{
        if (isShowing()) {
            if (! (peer instanceof LightweightPeer)) {
                g.clearRect(0, 0, width, height);
            }
            paint(g);
        }
}

Updates the container. This forwards the update to any lightweight components that are children of this container. If this method is reimplemented, super.update(g) should be called so that lightweight components are properly rendered. If a child component is entirely clipped by the current clipping setting in g, update() will not be forwarded to that child.

 public  void validate() 
{
        /* Avoid grabbing lock unless really necessary. */
        if (!valid) {
            boolean updateCur = false;
            synchronized (getTreeLock()) {
                if (!valid && peer != null) {
                    ContainerPeer p = null;
                    if (peer instanceof ContainerPeer) {
                        p = (ContainerPeer) peer;
                    }
                    if (p != null) {
                        p.beginValidate();
                    }
                    validateTree();
                    valid = true;
                    if (p != null) {
                        p.endValidate();
                        updateCur = isVisible();
                    }
                }
            }
            if (updateCur) {
                updateCursorImmediately();
            }
        }
}

Validates this container and all of its subcomponents.

The validate method is used to cause a container to lay out its subcomponents again. It should be invoked when this container's subcomponents are modified (added to or removed from the container, or layout-related information changed) after the container has been displayed.

If this {@code Container} is not valid, this method invokes the {@code validateTree} method and marks this {@code Container} as valid. Otherwise, no action is performed.

 protected  void validateTree() 
{
        if (!valid) {
            if (peer instanceof ContainerPeer) {
                ((ContainerPeer)peer).beginLayout();
            }
            doLayout();
            Component component[] = this.component;
            for (int i = 0 ; i <  ncomponents ; ++i) {
                Component comp = component[i];
                if (   (comp instanceof Container)
                    && !(comp instanceof Window)
                    && !comp.valid) {
                    ((Container)comp).validateTree();
                } else {
                    comp.validate();
                }
            }
            if (peer instanceof ContainerPeer) {
                ((ContainerPeer)peer).endLayout();
            }
        }
        valid = true;
}

Recursively descends the container tree and recomputes the layout for any subtrees marked as needing it (those marked as invalid). Synchronization should be provided by the method that calls this one: validate.