Constructor Detail

• LayoutFocusTraversalPolicy

  public LayoutFocusTraversalPolicy()

  Constructs a LayoutFocusTraversalPolicy.

Method Detail

• getComponentAfter

  public Component getComponentAfter(Container aContainer,
                            Component aComponent)

  Returns the Component that should receive the focus after aComponent. aContainer must be a focus cycle root of aComponent.

  By default, LayoutFocusTraversalPolicy 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.

  Overrides:

  getComponentAfter in class SortingFocusTraversalPolicy

  Parameters:

  aContainer - a focus cycle root of aComponent or a 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 - 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

  public Component getComponentBefore(Container aContainer,
                             Component aComponent)

  Returns the Component that should receive the focus before aComponent. aContainer must be a focus cycle root of aComponent.

  By default, LayoutFocusTraversalPolicy 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.

  Overrides:

  getComponentBefore in class SortingFocusTraversalPolicy

  Parameters:

  aContainer - a focus cycle root of aComponent or a 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 - 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

  public Component getFirstComponent(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.

  Overrides:

  getFirstComponent in class SortingFocusTraversalPolicy

  Parameters:

  aContainer - a 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, or null if no suitable Component can be found

  Throws:

  IllegalArgumentException - if aContainer is null

• getLastComponent

  public Component getLastComponent(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.

  Overrides:

  getLastComponent in class SortingFocusTraversalPolicy

  Parameters:

  aContainer - a 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, or null if no suitable Component can be found

  Throws:

  IllegalArgumentException - if aContainer is null

• accept

  protected boolean accept(Component aComponent)

  Determines whether the specified Component is an acceptable choice as the new focus owner. This method performs the following sequence of operations:

  1. Checks whether aComponent is visible, displayable, enabled, and focusable. If any of these properties is false, this method returns false.
  2. If aComponent is an instance of JTable, returns true.
  3. If aComponent is an instance of JComboBox, then returns the value of aComponent.getUI().isFocusTraversable(aComponent).
  4. If aComponent is a JComponent with a JComponent.WHEN_FOCUSED InputMap that is neither null nor empty, returns true.
  5. Returns the value of DefaultFocusTraversalPolicy.accept(aComponent).

  Overrides:

  accept in class SortingFocusTraversalPolicy

  Parameters:

  aComponent - the Component whose fitness as a focus owner is to be tested

  Returns:

  true if aComponent is a valid choice for a focus owner; otherwise false

  See Also:

  Component.isVisible(), Component.isDisplayable(), Component.isEnabled(), Component.isFocusable(), ComboBoxUI.isFocusTraversable(javax.swing.JComboBox), JComponent.getInputMap(int), DefaultFocusTraversalPolicy.accept(java.awt.Component)