Container (Java Platform SE 8 ) (original) (raw)

public int getComponentCount()
Gets the number of components in this panel.
Note: This method should be called under AWT tree lock.
Returns:
the number of components in this panel.
Since:
JDK1.1
See Also:
getComponent(int), Component.getTreeLock()

@Deprecated
public int countComponents()
Deprecated.

public Component getComponent(int n)
Gets the nth component in this container.
Note: This method should be called under AWT tree lock.
Parameters:
n - the index of the component to get.
Returns:
the nth component in this container.
Throws:
[ArrayIndexOutOfBoundsException](../../java/lang/ArrayIndexOutOfBoundsException.html "class in java.lang") - if the nth value does not exist.
See Also:
Component.getTreeLock()

public Component[] getComponents()
Gets all the components in this container.
Note: This method should be called under AWT tree lock.
Returns:
an array of all the components in this container.
See Also:
Component.getTreeLock()

public Insets getInsets()
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.
Returns:
the insets of this container.
Since:
JDK1.1
See Also:
Insets, LayoutManager

@Deprecated
public Insets insets()
Deprecated.

public Component add(Component comp)
Appends the specified component to the end of this container. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int).
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
Parameters:
comp - the component to be added
Returns:
the component argument
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp is null
See Also:
addImpl(java.awt.Component, java.lang.Object, int), invalidate(), validate(), JComponent.revalidate()

public Component add(String name,
Component comp)
Adds the specified component to this container. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int).
This method is obsolete as of 1.1. Please use the method add(Component, Object) instead.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp is null
See Also:
add(Component, Object), invalidate()

public Component add(Component comp,
int index)
Adds the specified component to this container at the given position. This is a convenience method for addImpl(java.awt.Component, java.lang.Object, int).
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
Parameters:
comp - the component to be added
index - the position at which to insert the component, or -1 to append the component to the end
Returns:
the component comp
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp is null
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if index is invalid (seeaddImpl(java.awt.Component, java.lang.Object, int) for details)
See Also:
addImpl(java.awt.Component, java.lang.Object, int), remove(int), invalidate(), validate(), JComponent.revalidate()

public void setComponentZOrder(Component comp,
int 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 andjava.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.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
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.
Parameters:
comp - the component to be moved
index - the position in the container's list to insert the component, where getComponentCount() appends to the end
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp isnull
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if comp is one of the container's parents
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if index is not in the range [0, getComponentCount()] for moving between containers, or not in the range[0, getComponentCount()-1] for moving inside a container
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if adding a container to itself
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if adding a Window to a container
Since:
1.5
See Also:
getComponentZOrder(java.awt.Component), invalidate()

public int getComponentZOrder(Component comp)
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.
Parameters:
comp - the component being queried
Returns:
the z-order index of the component; otherwise returns -1 if the component is null or doesn't belong to the container
Since:
1.5
See Also:
setComponentZOrder(java.awt.Component, int)

public void add(Component comp,
Object constraints)
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(java.awt.Component, java.lang.Object, int).
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
Parameters:
comp - the component to be added
constraints - an object expressing layout constraints for this component
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp is null
Since:
JDK1.1
See Also:
addImpl(java.awt.Component, java.lang.Object, int), invalidate(), validate(), JComponent.revalidate(), LayoutManager

public void add(Component comp,
Object constraints,
int 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(java.awt.Component, java.lang.Object, int).
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
Parameters:
comp - the component to be added
constraints - an object expressing layout constraints for this
index - the position in the container's list at which to insert the component; -1 means insert at the end component
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp is null
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if index is invalid (seeaddImpl(java.awt.Component, java.lang.Object, int) for details)
See Also:
addImpl(java.awt.Component, java.lang.Object, int), invalidate(), validate(), JComponent.revalidate(), remove(int), LayoutManager

protected void addImpl(Component comp,
Object constraints,
int index)
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 aGridBagConstraints object. Failure to pass the correct type of constraints object results in anIllegalArgumentException.
If the current layout manager implements LayoutManager2, thenLayoutManager2.addLayoutComponent(Component,Object) is invoked on it. If the current layout manager does not implementLayoutManager2, and constraints is a String, thenLayoutManager.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)
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to display the added component.
Parameters:
comp - the component to be added
constraints - an object expressing layout constraints for this component
index - the position in the container's list at which to insert the component, where -1 means append to the end
Throws:
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if index is invalid; if comp is a child of this container, the valid range is [-1, getComponentCount()-1]; if component is not a child of this container, the valid range is[-1, getComponentCount()]
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if comp is an ancestor of this container
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if adding a window to a container
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp is null
Since:
JDK1.1
See Also:
add(Component), add(Component, int), add(Component, java.lang.Object), invalidate(), LayoutManager, LayoutManager2

public void remove(int index)
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 theremoveLayoutComponent method.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
Parameters:
index - the index of the component to be removed
Throws:
[ArrayIndexOutOfBoundsException](../../java/lang/ArrayIndexOutOfBoundsException.html "class in java.lang") - if index is not in range [0, getComponentCount()-1]
Since:
JDK1.1
See Also:
add(java.awt.Component), invalidate(), validate(), getComponentCount()

public void remove(Component comp)
Removes the specified component from this container. This method also notifies the layout manager to remove the component from this container's layout via theremoveLayoutComponent method.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
Parameters:
comp - the component to be removed
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if comp is null
See Also:
add(java.awt.Component), invalidate(), validate(), remove(int)

public void removeAll()
Removes all the components from this container. This method also notifies the layout manager to remove the components from this container's layout via theremoveLayoutComponent method.
This method changes layout-related information, and therefore, invalidates the component hierarchy. If the container has already been displayed, the hierarchy must be validated thereafter in order to reflect the changes.
See Also:
add(java.awt.Component), remove(int), invalidate()

public LayoutManager getLayout()
Gets the layout manager for this container.
See Also:
doLayout(), setLayout(java.awt.LayoutManager)

public void setLayout(LayoutManager mgr)
Sets the layout manager for this container.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
Parameters:
mgr - the specified layout manager
See Also:
doLayout(), getLayout(), invalidate()

public void doLayout()
Causes this container to lay out its components. Most programs should not call this method directly, but should invoke the validate method instead.
Overrides:
[doLayout](../../java/awt/Component.html#doLayout--) in class [Component](../../java/awt/Component.html "class in java.awt")
Since:
JDK1.1
See Also:
LayoutManager.layoutContainer(java.awt.Container), setLayout(java.awt.LayoutManager), validate()

@Deprecated
public void layout()
Deprecated.
Overrides:
[layout](../../java/awt/Component.html#layout--) in class [Component](../../java/awt/Component.html "class in java.awt")

public boolean isValidateRoot()
Indicates if this container is a validate root.
Layout-related changes, such as bounds of the validate root descendants, do not affect the layout of the validate root parent. This peculiarity enables the invalidate() method to stop invalidating the component hierarchy when the method encounters a validate root. However, to preserve backward compatibility this new optimized behavior is enabled only when the java.awt.smartInvalidate system property value is set to true.
If a component hierarchy contains validate roots and the new optimizedinvalidate() behavior is enabled, the validate() method must be invoked on the validate root of a previously invalidated component to restore the validity of the hierarchy later. Otherwise, calling the validate() method on the top-level container (such as a Frame object) should be used to restore the validity of the component hierarchy.
The Window class and the Applet class are the validate roots in AWT. Swing introduces more validate roots.
Returns:
whether this container is a validate root
Since:
1.7
See Also:
invalidate(), Component.invalidate(), JComponent.isValidateRoot(), JComponent.revalidate()

public void invalidate()
Invalidates the container.
If the LayoutManager installed on this container is an instance of the LayoutManager2 interface, then the LayoutManager2.invalidateLayout(Container) method is invoked on it supplying this Container as the argument.
Afterwards this method marks this container invalid, and invalidates its ancestors. See the Component.invalidate() method for more details.
Overrides:
[invalidate](../../java/awt/Component.html#invalidate--) in class [Component](../../java/awt/Component.html "class in java.awt")
See Also:
validate(), layout(), LayoutManager2

public void validate()
Validates this container and all of its subcomponents.
Validating a container means laying out its subcomponents. Layout-related changes, such as setting the bounds of a component, or adding a component to the container, invalidate the container automatically. Note that the ancestors of the container may be invalidated also (see Component.invalidate() for details.) Therefore, to restore the validity of the hierarchy, the validate() method should be invoked on the top-most invalid container of the hierarchy.
Validating the container may be a quite time-consuming operation. For performance reasons a developer may postpone the validation of the hierarchy till a set of layout-related operations completes, e.g. after adding all the children to the container.
If this Container is not valid, this method invokes the validateTree method and marks this Container as valid. Otherwise, no action is performed.
Overrides:
[validate](../../java/awt/Component.html#validate--) in class [Component](../../java/awt/Component.html "class in java.awt")
See Also:
add(java.awt.Component), invalidate(), isValidateRoot(), JComponent.revalidate(), validateTree()

protected void validateTree()
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.
See Also:
doLayout(), validate()

public void setFont(Font f)
Sets the font of this container.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
Overrides:
[setFont](../../java/awt/Component.html#setFont-java.awt.Font-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
f - The font to become this container's font.
Since:
JDK1.0
See Also:
Component.getFont(), invalidate()

public Dimension getPreferredSize()
Returns the preferred size of this container. If the preferred size has not been set explicitly by Component.setPreferredSize(Dimension) and this Container has a non-null LayoutManager, then LayoutManager.preferredLayoutSize(Container) is used to calculate the preferred size.
Note: some implementations may cache the value returned from theLayoutManager. Implementations that cache need not invokepreferredLayoutSize on the LayoutManager every time this method is invoked, rather the LayoutManager will only be queried after the Container becomes invalid.
Overrides:
[getPreferredSize](../../java/awt/Component.html#getPreferredSize--) in class [Component](../../java/awt/Component.html "class in java.awt")
Returns:
an instance of Dimension that represents the preferred size of this container.
See Also:
getMinimumSize(), getMaximumSize(), getLayout(), LayoutManager.preferredLayoutSize(Container), Component.getPreferredSize()

@Deprecated
public Dimension preferredSize()
Deprecated.
Overrides:
[preferredSize](../../java/awt/Component.html#preferredSize--) in class [Component](../../java/awt/Component.html "class in java.awt")

public Dimension getMinimumSize()
Returns the minimum size of this container. If the minimum size has not been set explicitly by Component.setMinimumSize(Dimension) and this Container has a non-null LayoutManager, then LayoutManager.minimumLayoutSize(Container) is used to calculate the minimum size.
Note: some implementations may cache the value returned from theLayoutManager. Implementations that cache need not invokeminimumLayoutSize on the LayoutManager every time this method is invoked, rather the LayoutManager will only be queried after the Container becomes invalid.
Overrides:
[getMinimumSize](../../java/awt/Component.html#getMinimumSize--) in class [Component](../../java/awt/Component.html "class in java.awt")
Returns:
an instance of Dimension that represents the minimum size of this container.
Since:
JDK1.1
See Also:
getPreferredSize(), getMaximumSize(), getLayout(), LayoutManager.minimumLayoutSize(Container), Component.getMinimumSize()

@Deprecated
public Dimension minimumSize()
Deprecated.
Overrides:
[minimumSize](../../java/awt/Component.html#minimumSize--) in class [Component](../../java/awt/Component.html "class in java.awt")

public Dimension getMaximumSize()
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 Container is an instance of LayoutManager2, thenLayoutManager2.maximumLayoutSize(Container) is used to calculate the maximum size.
Note: some implementations may cache the value returned from theLayoutManager2. Implementations that cache need not invokemaximumLayoutSize on the LayoutManager2 every time this method is invoked, rather the LayoutManager2 will only be queried after the Container becomes invalid.
Overrides:
[getMaximumSize](../../java/awt/Component.html#getMaximumSize--) in class [Component](../../java/awt/Component.html "class in java.awt")
Returns:
an instance of Dimension that represents the maximum size of this container.
See Also:
getPreferredSize(), getMinimumSize(), getLayout(), LayoutManager2.maximumLayoutSize(Container), Component.getMaximumSize()

public float getAlignmentX()
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.
Overrides:
[getAlignmentX](../../java/awt/Component.html#getAlignmentX--) in class [Component](../../java/awt/Component.html "class in java.awt")

public float getAlignmentY()
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.
Overrides:
[getAlignmentY](../../java/awt/Component.html#getAlignmentY--) in class [Component](../../java/awt/Component.html "class in java.awt")

public void paint(Graphics g)
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.
Overrides:
[paint](../../java/awt/Component.html#paint-java.awt.Graphics-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
g - the specified Graphics window
See Also:
Component.update(Graphics)

public void update(Graphics 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.
Overrides:
[update](../../java/awt/Component.html#update-java.awt.Graphics-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
g - the specified Graphics window
See Also:
Component.update(Graphics)

public void print(Graphics g)
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.
Overrides:
[print](../../java/awt/Component.html#print-java.awt.Graphics-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
g - the specified Graphics window
See Also:
Component.update(Graphics)

public void paintComponents(Graphics g)
Paints each of the components in this container.
Parameters:
g - the graphics context.
See Also:
Component.paint(java.awt.Graphics), Component.paintAll(java.awt.Graphics)

public void printComponents(Graphics g)
Prints each of the components in this container.
Parameters:
g - the graphics context.
See Also:
Component.print(java.awt.Graphics), Component.printAll(java.awt.Graphics)

public void addContainerListener(ContainerListener l)
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.
Parameters:
l - the container listener
See Also:
removeContainerListener(java.awt.event.ContainerListener), getContainerListeners()

public void removeContainerListener(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.
Parameters:
l - the container listener
See Also:
addContainerListener(java.awt.event.ContainerListener), getContainerListeners()

public ContainerListener[] getContainerListeners()
Returns an array of all the container listeners registered on this container.
Returns:
all of this container's ContainerListeners or an empty array if no container listeners are currently registered
Since:
1.4
See Also:
addContainerListener(java.awt.event.ContainerListener), removeContainerListener(java.awt.event.ContainerListener)

public <T extends EventListener> T[] getListeners(Class listenerType)
Returns an array of all the objects currently registered as _Foo_Listeners upon this Container._Foo_Listeners are registered using theadd_Foo_Listener method.
You can specify the listenerType argument with a class literal, such as_Foo_Listener.class. For example, you can query aContainer 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.
Overrides:
[getListeners](../../java/awt/Component.html#getListeners-java.lang.Class-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
listenerType - the type of listeners requested; this parameter should specify an interface that descends fromjava.util.EventListener
Returns:
an array of all objects registered as_Foo_Listeners on this container, or an empty array if no such listeners have been added
Throws:
[ClassCastException](../../java/lang/ClassCastException.html "class in java.lang") - if listenerType doesn't specify a class or interface that implementsjava.util.EventListener
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if listenerType is null
Since:
1.3
See Also:
getContainerListeners()

protected void processEvent(AWTEvent e)
Processes events on this container. If the event is aContainerEvent, it invokes theprocessContainerEvent 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.
Overrides:
[processEvent](../../java/awt/Component.html#processEvent-java.awt.AWTEvent-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
e - the event
See Also:
Component.processComponentEvent(java.awt.event.ComponentEvent), Component.processFocusEvent(java.awt.event.FocusEvent), Component.processKeyEvent(java.awt.event.KeyEvent), Component.processMouseEvent(java.awt.event.MouseEvent), Component.processMouseMotionEvent(java.awt.event.MouseEvent), Component.processInputMethodEvent(java.awt.event.InputMethodEvent), Component.processHierarchyEvent(java.awt.event.HierarchyEvent), Component.processMouseWheelEvent(java.awt.event.MouseWheelEvent)

protected void processContainerEvent(ContainerEvent e)
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:

@Deprecated
public void deliverEvent(Event e)
Deprecated.
Overrides:
[deliverEvent](../../java/awt/Component.html#deliverEvent-java.awt.Event-) in class [Component](../../java/awt/Component.html "class in java.awt")

public Component getComponentAt(int x,
int 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).
Overrides:
[getComponentAt](../../java/awt/Component.html#getComponentAt-int-int-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
x - the x coordinate
y - the y coordinate
Returns:
null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned; otherwise the top-most child is returned.
Since:
JDK1.1
See Also:
Component.contains(int, int)

@Deprecated
public Component locate(int x,
int y)
Deprecated.
Overrides:
[locate](../../java/awt/Component.html#locate-int-int-) in class [Component](../../java/awt/Component.html "class in java.awt")

public Component getComponentAt(Point p)
Gets the component that contains the specified point.
Overrides:
[getComponentAt](../../java/awt/Component.html#getComponentAt-java.awt.Point-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
p - the point.
Returns:
returns the component that contains the point, or null if the component does not contain the point.
Since:
JDK1.1
See Also:
Component.contains(int, int)

public Point getMousePosition(boolean allowChildren)
throws HeadlessException
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.
Parameters:
allowChildren - true if children should be taken into account
Returns:
mouse coordinates relative to this Component, or null
Throws:
[HeadlessException](../../java/awt/HeadlessException.html "class in java.awt") - if GraphicsEnvironment.isHeadless() returns true
Since:
1.5
See Also:
Component.getMousePosition()

public Component findComponentAt(int x,
int y)
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.
Parameters:
x - the x coordinate
y - the y coordinate
Returns:
null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned.
Since:
1.2
See Also:
Component.contains(int, int), getComponentAt(int, int)

public Component findComponentAt(Point p)
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.
Parameters:
p - the point.
Returns:
null if the component does not contain the position. If there is no child component at the requested point and the point is within the bounds of the container the container itself is returned.
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if p is null
Since:
1.2
See Also:
Component.contains(int, int), getComponentAt(int, int)

public void addNotify()
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.
Overrides:
[addNotify](../../java/awt/Component.html#addNotify--) in class [Component](../../java/awt/Component.html "class in java.awt")
See Also:
Component.isDisplayable(), removeNotify()

public void 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.
Overrides:
[removeNotify](../../java/awt/Component.html#removeNotify--) in class [Component](../../java/awt/Component.html "class in java.awt")
See Also:
Component.isDisplayable(), addNotify()

public boolean isAncestorOf(Component c)
Checks if the component is contained in the component hierarchy of this container.
Parameters:
c - the component
Returns:
true if it is an ancestor;false otherwise.
Since:
JDK1.1

protected String paramString()
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 benull.
Overrides:
[paramString](../../java/awt/Component.html#paramString--) in class [Component](../../java/awt/Component.html "class in java.awt")
Returns:
the parameter string of this container

public void list(PrintStream out,
int indent)
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.
Overrides:
[list](../../java/awt/Component.html#list-java.io.PrintStream-int-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
out - a print stream
indent - the number of spaces to indent
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if out is null
Since:
JDK1.0
See Also:
Component.list(java.io.PrintStream, int)

public void list(PrintWriter out,
int indent)
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.
Overrides:
[list](../../java/awt/Component.html#list-java.io.PrintWriter-int-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
out - a print writer
indent - the number of spaces to indent
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if out is null
Since:
JDK1.1
See Also:
Component.list(java.io.PrintWriter, int)

public void setFocusTraversalKeys(int id,
Set<? extends AWTKeyStroke> 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.
This method may throw a ClassCastException if any Object in keystrokes is not an AWTKeyStroke.
Overrides:
[setFocusTraversalKeys](../../java/awt/Component.html#setFocusTraversalKeys-int-java.util.Set-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
id - one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
keystrokes - the Set of AWTKeyStroke for the specified operation
Throws:
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS, or if keystrokes contains null, or if any keystroke represents a KEY_TYPED event, or if any keystroke already maps to another focus traversal operation for this Container
Since:
1.4
See Also:
getFocusTraversalKeys(int), KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS

public Set<AWTKeyStroke> getFocusTraversalKeys(int id)
Returns the Set of focus traversal keys for a given traversal operation for this Container. (SeesetFocusTraversalKeys 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.
Overrides:
[getFocusTraversalKeys](../../java/awt/Component.html#getFocusTraversalKeys-int-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
id - one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
Returns:
the Set of AWTKeyStrokes for the specified operation. The Set will be unmodifiable, and may be empty. null will never be returned.
Throws:
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
Since:
1.4
See Also:
setFocusTraversalKeys(int, java.util.Set<? extends java.awt.AWTKeyStroke>), KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS

public boolean areFocusTraversalKeysSet(int id)
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.
Overrides:
[areFocusTraversalKeysSet](../../java/awt/Component.html#areFocusTraversalKeysSet-int-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
id - one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
Returns:
true if the the Set of focus traversal keys for the given focus traversal operation has been explicitly defined for this Component; false otherwise.
Throws:
[IllegalArgumentException](../../java/lang/IllegalArgumentException.html "class in java.lang") - if id is not one of KeyboardFocusManager.FORWARD_TRAVERSAL_KEYS, KeyboardFocusManager.BACKWARD_TRAVERSAL_KEYS, KeyboardFocusManager.UP_CYCLE_TRAVERSAL_KEYS, or KeyboardFocusManager.DOWN_CYCLE_TRAVERSAL_KEYS
Since:
1.4

public boolean isFocusCycleRoot(Container 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.
Overrides:
[isFocusCycleRoot](../../java/awt/Component.html#isFocusCycleRoot-java.awt.Container-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
container - the Container to be tested
Returns:
true if the specified Container is a focus-cycle- root of this Container; false otherwise
Since:
1.4
See Also:
isFocusCycleRoot()

public void setFocusTraversalPolicy(FocusTraversalPolicy 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.
Parameters:
policy - the new focus traversal policy for this Container
Since:
1.4
See Also:
getFocusTraversalPolicy(), setFocusCycleRoot(boolean), isFocusCycleRoot(java.awt.Container)

public FocusTraversalPolicy getFocusTraversalPolicy()
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.
Returns:
this Container's focus traversal policy, or null if this Container is not a focus cycle root.
Since:
1.4
See Also:
setFocusTraversalPolicy(java.awt.FocusTraversalPolicy), setFocusCycleRoot(boolean), isFocusCycleRoot(java.awt.Container)

public boolean isFocusTraversalPolicySet()
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.
Returns:
true if the focus traversal policy has been explicitly set for this Container; false otherwise.
Since:
1.4

public void setFocusCycleRoot(boolean 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 afocus traversal policy provider.
Parameters:
focusCycleRoot - indicates whether this Container is the root of a focus traversal cycle
Since:
1.4
See Also:
isFocusCycleRoot(), setFocusTraversalPolicy(java.awt.FocusTraversalPolicy), getFocusTraversalPolicy(), ContainerOrderFocusTraversalPolicy, setFocusTraversalPolicyProvider(boolean)

public boolean isFocusCycleRoot()
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.
Returns:
whether this Container is the root of a focus traversal cycle
Since:
1.4
See Also:
setFocusCycleRoot(boolean), setFocusTraversalPolicy(java.awt.FocusTraversalPolicy), getFocusTraversalPolicy(), ContainerOrderFocusTraversalPolicy

public final void setFocusTraversalPolicyProvider(boolean provider)
Sets whether this container will be used to provide focus traversal policy. Container with this property astrue will be used to acquire focus traversal policy instead of closest focus cycle root ancestor.
Parameters:
provider - indicates whether this container will be used to provide focus traversal policy
Since:
1.5
See Also:
setFocusTraversalPolicy(java.awt.FocusTraversalPolicy), getFocusTraversalPolicy(), isFocusTraversalPolicyProvider()

public final boolean isFocusTraversalPolicyProvider()
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.
Returns:
true if this container provides focus traversal policy, false otherwise
Since:
1.5
See Also:
setFocusTraversalPolicy(java.awt.FocusTraversalPolicy), getFocusTraversalPolicy(), setFocusCycleRoot(boolean), setFocusTraversalPolicyProvider(boolean)

public void transferFocusDownCycle()
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.
Since:
1.4
See Also:
Component.requestFocus(), isFocusCycleRoot(java.awt.Container), setFocusCycleRoot(boolean)

public void applyComponentOrientation(ComponentOrientation o)
Sets the ComponentOrientation property of this container and all components contained within it.
This method changes layout-related information, and therefore, invalidates the component hierarchy.
Overrides:
[applyComponentOrientation](../../java/awt/Component.html#applyComponentOrientation-java.awt.ComponentOrientation-) in class [Component](../../java/awt/Component.html "class in java.awt")
Parameters:
o - the new component orientation of this container and the components contained within it.
Throws:
[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - if orientation is null.
Since:
1.4
See Also:
Component.setComponentOrientation(java.awt.ComponentOrientation), Component.getComponentOrientation(), invalidate()

public void addPropertyChangeListener(PropertyChangeListener listener)
Adds a PropertyChangeListener to the listener list. The listener is registered for all bound properties of this class, including the following:

public void addPropertyChangeListener(String propertyName,
PropertyChangeListener 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: