JavaTM 2 Platform
Std. Ed. v1.4.2

java.awt
Class ContainerOrderFocusTraversalPolicy

java.lang.Object
  extended byjava.awt.FocusTraversalPolicy
      extended byjava.awt.ContainerOrderFocusTraversalPolicy
All Implemented Interfaces:
Serializable
Direct Known Subclasses:
DefaultFocusTraversalPolicy

public class ContainerOrderFocusTraversalPolicy
extends FocusTraversalPolicy
implements Serializable

A FocusTraversalPolicy that determines traversal order based on the order of child Components in a Container. From a particular focus cycle root, the policy makes a pre-order traversal of the Component hierarchy, and traverses a Container's children according to the ordering of the array returned by Container.getComponents(). Portions of the hierarchy that are not visible and displayable will not be searched.

By default, ContainerOrderFocusTraversalPolicy implicitly transfers focus down-cycle. That is, during normal forward focus traversal, the Component traversed after a focus cycle root will be the focus-cycle-root's default Component to focus. This behavior can be disabled using the setImplicitDownCycleTraversal method.

By default, methods of this class with return a Component only if it is visible, displayable, enabled, and focusable. Subclasses can modify this behavior by overriding the accept method.

Since:
1.4
See Also:
Container.getComponents(), Serialized Form

Constructor Summary
ContainerOrderFocusTraversalPolicy()
           
 
Method Summary
protected  boolean accept(Component aComponent)
          Determines whether a Component is an acceptable choice as the new focus owner.
 Component getComponentAfter(Container focusCycleRoot, Component aComponent)
          Returns the Component that should receive the focus after aComponent.
 Component getComponentBefore(Container focusCycleRoot, Component aComponent)
          Returns the Component that should receive the focus before aComponent.
 Component getDefaultComponent(Container focusCycleRoot)
          Returns the default Component to focus.
 Component getFirstComponent(Container focusCycleRoot)
          Returns the first Component in the traversal cycle.
 boolean getImplicitDownCycleTraversal()
          Returns whether this ContainerOrderFocusTraversalPolicy transfers focus down-cycle implicitly.
 Component getLastComponent(Container focusCycleRoot)
          Returns the last Component in the traversal cycle.
 void setImplicitDownCycleTraversal(boolean implicitDownCycleTraversal)
          Sets whether this ContainerOrderFocusTraversalPolicy transfers focus down-cycle implicitly.
 
Methods inherited from class java.awt.FocusTraversalPolicy
getInitialComponent
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

ContainerOrderFocusTraversalPolicy

public ContainerOrderFocusTraversalPolicy()
Method Detail

getComponentAfter

public Component getComponentAfter(Container focusCycleRoot,
                                   Component aComponent)
Returns the Component that should receive the focus after aComponent. focusCycleRoot must be a focus cycle root of aComponent.

By default, ContainerOrderFocusTraversalPolicy implicitly transfers focus down-cycle. That is, during normal forward focus traversal, the Component traversed after a focus cycle root will be the focus-cycle- root's default Component to focus. This behavior can be disabled using the setImplicitDownCycleTraversal method.

Specified by:
getComponentAfter in class FocusTraversalPolicy
Parameters:
focusCycleRoot - a focus cycle root of aComponent
aComponent - a (possibly indirect) child of focusCycleRoot, or focusCycleRoot itself
Returns:
the Component that should receive the focus after aComponent, or null if no suitable Component can be found
Throws:
IllegalArgumentException - if focusCycleRoot is not a focus cycle root of aComponent, or if either focusCycleRoot or aComponent is null

getComponentBefore

public Component getComponentBefore(Container focusCycleRoot,
                                    Component aComponent)
Returns the Component that should receive the focus before aComponent. focusCycleRoot must be a focus cycle root of aComponent.

Specified by:
getComponentBefore in class FocusTraversalPolicy
Parameters:
focusCycleRoot - a focus cycle root of aComponent
aComponent - a (possibly indirect) child of focusCycleRoot, or focusCycleRoot itself
Returns:
the Component that should receive the focus before aComponent, or null if no suitable Component can be found
Throws:
IllegalArgumentException - if focusCycleRoot is not a focus cycle root of aComponent, or if either focusCycleRoot or aComponent is null

getFirstComponent

public Component getFirstComponent(Container focusCycleRoot)
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.

Specified by:
getFirstComponent in class FocusTraversalPolicy
Parameters:
focusCycleRoot - the focus cycle root whose first Component is to be returned
Returns:
the first Component in the traversal cycle when focusCycleRoot is the focus cycle root, or null if no suitable Component can be found
Throws:
IllegalArgumentException - if focusCycleRoot is null

getLastComponent

public Component getLastComponent(Container focusCycleRoot)
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.

Specified by:
getLastComponent in class FocusTraversalPolicy
Parameters:
focusCycleRoot - the focus cycle root whose last Component is to be returned
Returns:
the last Component in the traversal cycle when focusCycleRoot is the focus cycle root, or null if no suitable Component can be found
Throws:
IllegalArgumentException - if focusCycleRoot is null

getDefaultComponent

public Component getDefaultComponent(Container focusCycleRoot)
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 focusCycleRoot. The default implementation of this method returns the same Component as getFirstComponent.

Specified by:
getDefaultComponent in class FocusTraversalPolicy
Parameters:
focusCycleRoot - the focus cycle root whose default Component is to be returned
Returns:
the default Component in the traversal cycle when focusCycleRoot is the focus cycle root, or null if no suitable Component can be found
Throws:
IllegalArgumentException - if focusCycleRoot is null
See Also:
getFirstComponent(java.awt.Container)

setImplicitDownCycleTraversal

public void setImplicitDownCycleTraversal(boolean implicitDownCycleTraversal)
Sets whether this ContainerOrderFocusTraversalPolicy transfers focus down-cycle implicitly. If true, during normal forward focus traversal, the Component traversed after a focus cycle root will be the focus-cycle-root's default Component to focus. If false, the next Component in the focus traversal cycle rooted at the specified focus cycle root will be traversed instead. The default value for this property is true.

Parameters:
implicitDownCycleTraversal - whether this ContainerOrderFocusTraversalPolicy transfers focus down-cycle implicitly
See Also:
getImplicitDownCycleTraversal(), getFirstComponent(java.awt.Container)

getImplicitDownCycleTraversal

public boolean getImplicitDownCycleTraversal()
Returns whether this ContainerOrderFocusTraversalPolicy transfers focus down-cycle implicitly. If true, during normal forward focus traversal, the Component traversed after a focus cycle root will be the focus-cycle-root's default Component to focus. If false, the next Component in the focus traversal cycle rooted at the specified focus cycle root will be traversed instead.

Returns:
whether this ContainerOrderFocusTraversalPolicy transfers focus down-cycle implicitly
See Also:
setImplicitDownCycleTraversal(boolean), getFirstComponent(java.awt.Container)

accept

protected boolean accept(Component aComponent)
Determines whether a Component is an acceptable choice as the new focus owner. By default, this method will accept a Component if and only if it is visible, displayable, enabled, and focusable.

Parameters:
aComponent - the Component whose fitness as a focus owner is to be tested
Returns:
true if aComponent is visible, displayable, enabled, and focusable; false otherwise

JavaTM 2 Platform
Std. Ed. v1.4.2

Submit a bug or feature
For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2003 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.


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