java.awt
Class FocusTraversalPolicy

java.lang.Object sample code for java.lang.Object definition code for java.lang.Object 
  extended by java.awt.FocusTraversalPolicy
Direct Known Subclasses:
ContainerOrderFocusTraversalPolicy sample code for java.awt.ContainerOrderFocusTraversalPolicy definition code for java.awt.ContainerOrderFocusTraversalPolicy , InternalFrameFocusTraversalPolicy sample code for javax.swing.InternalFrameFocusTraversalPolicy definition code for javax.swing.InternalFrameFocusTraversalPolicy

public abstract class FocusTraversalPolicy
extends Object sample code for java.lang.Object definition code for java.lang.Object

A FocusTraversalPolicy defines the order in which Components with a particular focus cycle root are traversed. Instances can apply the policy to arbitrary focus cycle roots, allowing themselves to be shared across Containers. They do not need to be reinitialized when the focus cycle roots of a Component hierarchy change.

The core responsibility of a FocusTraversalPolicy is to provide algorithms determining the next and previous Components to focus when traversing forward or backward in a UI. Each FocusTraversalPolicy must also provide algorithms for determining the first, last, and default Components in a traversal cycle. First and last Components are used when normal forward and backward traversal, respectively, wraps. The default Component is the first to receive focus when traversing down into a new focus traversal cycle. A FocusTraversalPolicy can optionally provide an algorithm for determining a Window's initial Component. The initial Component is the first to receive focus when a Window is first made visible.

FocusTraversalPolicy takes into account focus traversal policy providers. When searching for first/last/next/previous Component, if a focus traversal policy provider is encountered, its focus traversal policy is used to perform the search operation.

Please see How to Use the Focus Subsystem, a section in The Java Tutorial, and the Focus Specification for more information.

Since:
1.4
See Also:
Container.setFocusTraversalPolicy(java.awt.FocusTraversalPolicy) sample code for java.awt.Container.setFocusTraversalPolicy(java.awt.FocusTraversalPolicy) definition code for java.awt.Container.setFocusTraversalPolicy(java.awt.FocusTraversalPolicy) , Container.getFocusTraversalPolicy() sample code for java.awt.Container.getFocusTraversalPolicy() definition code for java.awt.Container.getFocusTraversalPolicy() , Container.setFocusCycleRoot(boolean) sample code for java.awt.Container.setFocusCycleRoot(boolean) definition code for java.awt.Container.setFocusCycleRoot(boolean) , Container.isFocusCycleRoot(java.awt.Container) sample code for java.awt.Container.isFocusCycleRoot(java.awt.Container) definition code for java.awt.Container.isFocusCycleRoot(java.awt.Container) , Container.setFocusTraversalPolicyProvider(boolean) sample code for java.awt.Container.setFocusTraversalPolicyProvider(boolean) definition code for java.awt.Container.setFocusTraversalPolicyProvider(boolean) , Container.isFocusTraversalPolicyProvider() sample code for java.awt.Container.isFocusTraversalPolicyProvider() definition code for java.awt.Container.isFocusTraversalPolicyProvider() , KeyboardFocusManager.setDefaultFocusTraversalPolicy(java.awt.FocusTraversalPolicy) sample code for java.awt.KeyboardFocusManager.setDefaultFocusTraversalPolicy(java.awt.FocusTraversalPolicy) definition code for java.awt.KeyboardFocusManager.setDefaultFocusTraversalPolicy(java.awt.FocusTraversalPolicy) , KeyboardFocusManager.getDefaultFocusTraversalPolicy() sample code for java.awt.KeyboardFocusManager.getDefaultFocusTraversalPolicy() definition code for java.awt.KeyboardFocusManager.getDefaultFocusTraversalPolicy()

Constructor Summary
FocusTraversalPolicy sample code for java.awt.FocusTraversalPolicy.FocusTraversalPolicy() definition code for java.awt.FocusTraversalPolicy.FocusTraversalPolicy() ()
           
 
Method Summary
abstract  Component sample code for java.awt.Component definition code for java.awt.Component getComponentAfter sample code for java.awt.FocusTraversalPolicy.getComponentAfter(java.awt.Container, java.awt.Component) definition code for java.awt.FocusTraversalPolicy.getComponentAfter(java.awt.Container, java.awt.Component) (Container sample code for java.awt.Container definition code for java.awt.Container  aContainer, Component sample code for java.awt.Component definition code for java.awt.Component  aComponent)
          Returns the Component that should receive the focus after aComponent.
abstract  Component sample code for java.awt.Component definition code for java.awt.Component getComponentBefore sample code for java.awt.FocusTraversalPolicy.getComponentBefore(java.awt.Container, java.awt.Component) definition code for java.awt.FocusTraversalPolicy.getComponentBefore(java.awt.Container, java.awt.Component) (Container sample code for java.awt.Container definition code for java.awt.Container  aContainer, Component sample code for java.awt.Component definition code for java.awt.Component  aComponent)
          Returns the Component that should receive the focus before aComponent.
abstract  Component sample code for java.awt.Component definition code for java.awt.Component getDefaultComponent sample code for java.awt.FocusTraversalPolicy.getDefaultComponent(java.awt.Container) definition code for java.awt.FocusTraversalPolicy.getDefaultComponent(java.awt.Container) (Container sample code for java.awt.Container definition code for java.awt.Container  aContainer)
          Returns the default Component to focus.
abstract  Component sample code for java.awt.Component definition code for java.awt.Component getFirstComponent sample code for java.awt.FocusTraversalPolicy.getFirstComponent(java.awt.Container) definition code for java.awt.FocusTraversalPolicy.getFirstComponent(java.awt.Container) (Container sample code for java.awt.Container definition code for java.awt.Container  aContainer)
          Returns the first Component in the traversal cycle.
 Component sample code for java.awt.Component definition code for java.awt.Component getInitialComponent sample code for java.awt.FocusTraversalPolicy.getInitialComponent(java.awt.Window) definition code for java.awt.FocusTraversalPolicy.getInitialComponent(java.awt.Window) (Window sample code for java.awt.Window definition code for java.awt.Window  window)
          Returns the Component that should receive the focus when a Window is made visible for the first time.
abstract  Component sample code for java.awt.Component definition code for java.awt.Component getLastComponent sample code for java.awt.FocusTraversalPolicy.getLastComponent(java.awt.Container) definition code for java.awt.FocusTraversalPolicy.getLastComponent(java.awt.Container) (Container sample code for java.awt.Container definition code for java.awt.Container  aContainer)
          Returns the last Component in the traversal cycle.
 
Methods inherited from class java.lang.Object sample code for java.lang.Object definition code for java.lang.Object
clone sample code for java.lang.Object.clone() definition code for java.lang.Object.clone() , equals sample code for java.lang.Object.equals(java.lang.Object) definition code for java.lang.Object.equals(java.lang.Object) , finalize sample code for java.lang.Object.finalize() definition code for java.lang.Object.finalize() , getClass sample code for java.lang.Object.getClass() definition code for java.lang.Object.getClass() , hashCode sample code for java.lang.Object.hashCode() definition code for java.lang.Object.hashCode() , notify sample code for java.lang.Object.notify() definition code for java.lang.Object.notify() , notifyAll sample code for java.lang.Object.notifyAll() definition code for java.lang.Object.notifyAll() , toString sample code for java.lang.Object.toString() definition code for java.lang.Object.toString() , wait sample code for java.lang.Object.wait() definition code for java.lang.Object.wait() , wait sample code for java.lang.Object.wait(long) definition code for java.lang.Object.wait(long) , wait sample code for java.lang.Object.wait(long, int) definition code for java.lang.Object.wait(long, int)
 

Constructor Detail

FocusTraversalPolicy sample code for java.awt.FocusTraversalPolicy() definition code for java.awt.FocusTraversalPolicy()

public FocusTraversalPolicy()
Method Detail

getComponentAfter sample code for java.awt.FocusTraversalPolicy.getComponentAfter(java.awt.Container, java.awt.Component) definition code for java.awt.FocusTraversalPolicy.getComponentAfter(java.awt.Container, java.awt.Component)

public abstract Component sample code for java.awt.Component definition code for java.awt.Component  getComponentAfter(Container sample code for java.awt.Container definition code for java.awt.Container  aContainer,
                                            Component sample code for java.awt.Component definition code for java.awt.Component  aComponent)
Returns the Component that should receive the focus after aComponent. aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.

Parameters:
aContainer - a focus cycle root of aComponent or focus traversal policy provider
aComponent - a (possibly indirect) child of aContainer, or aContainer itself
Returns:
the Component that should receive the focus after aComponent, or null if no suitable Component can be found
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if aContainer is not a focus cycle root of aComponent or a focus traversal policy provider, or if either aContainer or aComponent is null

getComponentBefore sample code for java.awt.FocusTraversalPolicy.getComponentBefore(java.awt.Container, java.awt.Component) definition code for java.awt.FocusTraversalPolicy.getComponentBefore(java.awt.Container, java.awt.Component)

public abstract Component sample code for java.awt.Component definition code for java.awt.Component  getComponentBefore(Container sample code for java.awt.Container definition code for java.awt.Container  aContainer,
                                             Component sample code for java.awt.Component definition code for java.awt.Component  aComponent)
Returns the Component that should receive the focus before aComponent. aContainer must be a focus cycle root of aComponent or a focus traversal policy provider.

Parameters:
aContainer - a focus cycle root of aComponent or focus traversal policy provider
aComponent - a (possibly indirect) child of aContainer, or aContainer itself
Returns:
the Component that should receive the focus before aComponent, or null if no suitable Component can be found
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if aContainer is not a focus cycle root of aComponent or a focus traversal policy provider, or if either aContainer or aComponent is null

getFirstComponent sample code for java.awt.FocusTraversalPolicy.getFirstComponent(java.awt.Container) definition code for java.awt.FocusTraversalPolicy.getFirstComponent(java.awt.Container)

public abstract Component sample code for java.awt.Component definition code for java.awt.Component  getFirstComponent(Container sample code for java.awt.Container definition code for java.awt.Container  aContainer)
Returns the first Component in the traversal cycle. This method is used to determine the next Component to focus when traversal wraps in the forward direction.

Parameters:
aContainer - the focus cycle root or focus traversal policy provider whose first Component is to be returned
Returns:
the first Component in the traversal cycle of aContainer, or null if no suitable Component can be found
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if aContainer is null

getLastComponent sample code for java.awt.FocusTraversalPolicy.getLastComponent(java.awt.Container) definition code for java.awt.FocusTraversalPolicy.getLastComponent(java.awt.Container)

public abstract Component sample code for java.awt.Component definition code for java.awt.Component  getLastComponent(Container sample code for java.awt.Container definition code for java.awt.Container  aContainer)
Returns the last Component in the traversal cycle. This method is used to determine the next Component to focus when traversal wraps in the reverse direction.

Parameters:
aContainer - the focus cycle root or focus traversal policy provider whose last Component is to be returned
Returns:
the last Component in the traversal cycle of aContainer, or null if no suitable Component can be found
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if aContainer is null

getDefaultComponent sample code for java.awt.FocusTraversalPolicy.getDefaultComponent(java.awt.Container) definition code for java.awt.FocusTraversalPolicy.getDefaultComponent(java.awt.Container)

public abstract Component sample code for java.awt.Component definition code for java.awt.Component  getDefaultComponent(Container sample code for java.awt.Container definition code for java.awt.Container  aContainer)
Returns the default Component to focus. This Component will be the first to receive focus when traversing down into a new focus traversal cycle rooted at aContainer.

Parameters:
aContainer - the focus cycle root or focus traversal policy provider whose default Component is to be returned
Returns:
the default Component in the traversal cycle of aContainer, or null if no suitable Component can be found
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if aContainer is null

getInitialComponent sample code for java.awt.FocusTraversalPolicy.getInitialComponent(java.awt.Window) definition code for java.awt.FocusTraversalPolicy.getInitialComponent(java.awt.Window)

public Component sample code for java.awt.Component definition code for java.awt.Component  getInitialComponent(Window sample code for java.awt.Window definition code for java.awt.Window  window)
Returns the Component that should receive the focus when a Window is made visible for the first time. Once the Window has been made visible by a call to show() or setVisible(true), the initial Component will not be used again. Instead, if the Window loses and subsequently regains focus, or is made invisible or undisplayable and subsequently made visible and displayable, the Window's most recently focused Component will become the focus owner. The default implementation of this method returns the default Component.

Parameters:
window - the Window whose initial Component is to be returned
Returns:
the Component that should receive the focus when window is made visible for the first time, or null if no suitable Component can be found
Throws:
IllegalArgumentException sample code for java.lang.IllegalArgumentException definition code for java.lang.IllegalArgumentException - if window is null
See Also:
getDefaultComponent(java.awt.Container) sample code for java.awt.FocusTraversalPolicy.getDefaultComponent(java.awt.Container) definition code for java.awt.FocusTraversalPolicy.getDefaultComponent(java.awt.Container) , Window.getMostRecentFocusOwner() sample code for java.awt.Window.getMostRecentFocusOwner() definition code for java.awt.Window.getMostRecentFocusOwner()