java.awt.DefaultFocusTraversalPolicy Maven / Gradle / Ivy
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*/
package java.awt;
// import java.awt.peer.ComponentPeer;
// PBP/PP 6214663
/**
* 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.
*
* If client code has explicitly set the focusability of a Component by either
* overriding Component.isFocusTraversable() or
* Component.isFocusable(), or by calling
* Component.setFocusable(), then a DefaultFocusTraversalPolicy
* behaves exactly like a ContainerOrderFocusTraversalPolicy. If, however, the
* Component is relying on default focusability, then a
* DefaultFocusTraversalPolicy will reject all Components with non-focusable
* peers. This is the default FocusTraversalPolicy for all AWT Containers.
*
* The focusability of a peer is implementation-dependent. Sun recommends that
* all implementations for a particular native platform construct peers with
* the same focusability. The recommendations for Windows and Unix are that
* Canvases, Labels, Panels, Scrollbars, ScrollPanes, Windows, and lightweight
* Components have non-focusable peers, and all other Components have focusable
* peers. These recommendations are used in the Sun AWT implementations. Note
* that the focusability of a Component's peer is different from, and does not
* impact, the focusability of the Component itself.
*
* @author David Mendenhall
* @version 1.3, 01/23/03
*
* @see Container#getComponents
* @see Component#isFocusable
* @see Component#setFocusable
* @since 1.4
*/
public class DefaultFocusTraversalPolicy
extends ContainerOrderFocusTraversalPolicy
{
public DefaultFocusTraversalPolicy() { }
/**
* Determines whether a Component is an acceptable choice as the new
* focus owner. The Component must be visible, displayable, and enabled
* to be accepted. If client code has explicitly set the focusability
* of the Component by either overriding
* Component.isFocusTraversable() or
* Component.isFocusable(), or by calling
* Component.setFocusable(), then the Component will be
* accepted if and only if it is focusable. If, however, the Component is
* relying on default focusability, then all Canvases, Labels, Panels,
* Windows, and lightweight Components will be
* rejected.
*
* @param aComponent the Component whose fitness as a focus owner is to
* be tested
* @return true if aComponent meets the above requirements;
* false otherwise
*/
protected boolean accept(Component aComponent) { return false; }
}