javax.swing
Class SortingFocusTraversalPolicy

java.lang.Object
  java.awt.FocusTraversalPolicy
      javax.swing.InternalFrameFocusTraversalPolicy
          javax.swing.SortingFocusTraversalPolicy

Direct Known Subclasses:

LayoutFocusTraversalPolicy

public class SortingFocusTraversalPolicy

extends InternalFrameFocusTraversalPolicy

A FocusTraversalPolicy that determines traversal order by sorting the Components of a focus traversal cycle based on a given Comparator. Portions of the Component hierarchy that are not visible and displayable will not be included.

By default, SortingFocusTraversalPolicy implicitly transfers focus down- cycle. That is, during normal 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.

This policy 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.

Since:

1.4

See Also:

Comparator

Constructor Summary
protected	SortingFocusTraversalPolicy ()           Constructs a SortingFocusTraversalPolicy without a Comparator.
	SortingFocusTraversalPolicy ( Comparator  comparator)           Constructs a SortingFocusTraversalPolicy with the specified Comparator.

 

Method Summary
protected  boolean	accept ( Component  aComponent)           Determines whether a Component is an acceptable choice as the new focus owner.
protected   Comparator	getComparator ()           Returns the Comparator which will be used to sort the Components in a focus traversal cycle.
Component	getComponentAfter ( Container  aContainer,  focusCycleRoot, Component           Returns the Component that should receive the focus after aComponent.
Component	getComponentBefore ( Container  aContainer,  focusCycleRoot, Component           Returns the Component that should receive the focus before aComponent.
Component	getDefaultComponent ( Container           Returns the default Component to focus.
Component	getFirstComponent ( Container           Returns the first Component in the traversal cycle.
boolean	getImplicitDownCycleTraversal ()           Returns whether this SortingFocusTraversalPolicy transfers focus down- cycle implicitly.
Component	getLastComponent ( Container           Returns the last Component in the traversal cycle.
protected  void	setComparator ( Comparator  comparator)           Sets the Comparator which will be used to sort the Components in a focus traversal cycle.
void	setImplicitDownCycleTraversal (boolean implicitDownCycleTraversal)           Sets whether this SortingFocusTraversalPolicy transfers focus down-cycle implicitly.

 

Methods inherited from class javax.swing. InternalFrameFocusTraversalPolicy
getInitialComponent

 

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

SortingFocusTraversalPolicy

protected SortingFocusTraversalPolicy()

Constructs a SortingFocusTraversalPolicy without a Comparator. Subclasses must set the Comparator using setComparator before installing this FocusTraversalPolicy on a focus cycle root or KeyboardFocusManager.

SortingFocusTraversalPolicy

public SortingFocusTraversalPolicy(Comparator comparator)

Constructs a SortingFocusTraversalPolicy with the specified Comparator.

getComponentAfter

public ComponentgetComponentAfter(Container aContainer,
  focusCycleRoot,
 Component aComponent)

Returns the Component that should receive the focus after aComponent. aContainer focusCycleRoot must be a focus cycle root of aComponent or a focus traversal policy provider. aComponent.

By default, SortingFocusTraversalPolicy implicitly transfers focus down- cycle. That is, during normal 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.

If aContainer is focus traversal policy provider , the focus is always transferred down-cycle.

Specified by:

getComponentAfter in class FocusTraversalPolicy

Parameters:

aContainer focusCycleRoot - a focus cycle root of aComponent or a focus traversal policy provider

aComponent - a (possibly indirect) child of aContainer, focusCycleRoot, or aContainer focusCycleRoot itself

Returns:

the Component that should receive the focus after aComponent, or null if no suitable Component can be found

Throws:

IllegalArgumentException - if aContainer focusCycleRoot is not a focus cycle root of aComponent aComponent, or a focus traversal policy provider, or if either aContainer focusCycleRoot or aComponent is null

getComponentBefore

public ComponentgetComponentBefore(Container aContainer,
  focusCycleRoot,
 Component aComponent)

Returns the Component that should receive the focus before aComponent. aContainer focusCycleRoot must be a focus cycle root of aComponent or a focus traversal policy provider. aComponent.

By default, SortingFocusTraversalPolicy implicitly transfers focus down- cycle. That is, during normal 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.

If aContainer is focus traversal policy provider , the focus is always transferred down-cycle.

Specified by:

getComponentBefore in class FocusTraversalPolicy

Parameters:

aContainer focusCycleRoot - a focus cycle root of aComponent or a focus traversal policy provider

aComponent - a (possibly indirect) child of aContainer, focusCycleRoot, or aContainer focusCycleRoot itself

Returns:

the Component that should receive the focus before aComponent, or null if no suitable Component can be found

Throws:

IllegalArgumentException - if aContainer focusCycleRoot is not a focus cycle root of aComponent aComponent, or a focus traversal policy provider, or if either aContainer focusCycleRoot or aComponent is null

getFirstComponent

public ComponentgetFirstComponent(Container aContainer)  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:

aContainer focusCycleRoot - a the focus cycle root of aComponent or a focus traversal policy provider whose first Component is to be returned

Returns:

the first Component in the traversal cycle of aContainer, when focusCycleRoot is the focus cycle root, or null if no suitable Component can be found

Throws:

IllegalArgumentException - if aContainer focusCycleRoot is null

getLastComponent

public ComponentgetLastComponent(Container aContainer)  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:

aContainer focusCycleRoot - a the focus cycle root of aComponent or a focus traversal policy provider whose last Component is to be returned

Returns:

the last Component in the traversal cycle of aContainer, when focusCycleRoot is the focus cycle root, or null if no suitable Component can be found

Throws:

IllegalArgumentException - if aContainer focusCycleRoot is null

getDefaultComponent

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

Specified by:

getDefaultComponent in class FocusTraversalPolicy

Parameters:

aContainer focusCycleRoot - a the focus cycle root of aComponent or a focus traversal policy provider whose default Component is to be returned

Returns:

the default Component in the traversal cycle of aContainer, when focusCycleRoot is the focus cycle root, or null if no suitable Component can be found

Throws:

IllegalArgumentException - if aContainer focusCycleRoot is null

See Also:

getFirstComponent(java.awt.Container)

setImplicitDownCycleTraversal

public void setImplicitDownCycleTraversal(boolean implicitDownCycleTraversal)

Sets whether this SortingFocusTraversalPolicy transfers focus down-cycle implicitly. If true, during normal 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 SortingFocusTraversalPolicy transfers focus down-cycle implicitly

See Also:

getImplicitDownCycleTraversal() , getFirstComponent(java.awt.Container)

getImplicitDownCycleTraversal

public boolean getImplicitDownCycleTraversal()

Returns whether this SortingFocusTraversalPolicy transfers focus down- cycle implicitly. If true, during normal 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 SortingFocusTraversalPolicy transfers focus down- cycle implicitly

See Also:

setImplicitDownCycleTraversal(boolean) , getFirstComponent(java.awt.Container)

setComparator

protected void setComparator(Comparator comparator)

Sets the Comparator which will be used to sort the Components in a focus traversal cycle.

Parameters:

comparator - the Comparator which will be used for sorting

getComparator

protected Comparator getComparator()

Returns the Comparator which will be used to sort the Components in a focus traversal cycle.

Returns:

the Comparator which will be used for sorting

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