Hi Andreas,
Yes, in fact Petr has proposed this same enhancement back in January:
http://mail.openjdk.java.net/pipermail/awt-dev/2014-January/006799.html
Do you want to contribute a patch for this RFE? If so, please read this
document:
http://openjdk.java.net/contribute/
The most important part is to get your OCA signed, after which we can
accept patches from you.
--
best regards,
Anthony
On 8/24/2014 3:42 AM, Andreas Lundblad wrote:
For listener interfaces where it's common to just implement one or two
methods, there are corresponding Adapter classes with empty method
implementations. (For example: MouseListener/MouseAdapter,
KeyListener/KeyAdapter, ComponentListener/ComponentAdapter, ...)
The Adapter classes are really convenient for obvious reasons. However,
due to the constraint of single inheritance, they can't be used together
with each other. That is, if I want to listen to key presses
(KeyListener.keyPressed) and mouse clicks (MouseListener.mouseClicked)
I'm doomed to either
1) choose to extend one of the adapters and clutter my code with empty
method implementations for the other, or
2) Extend the two adapters in two separate classes and instantiate two
separate listener objects (which gets slightly messy if they need to
share some state).
Therefor I propose to add empty default implementations for these types
of listener interfaces. This would allow me to for instance implement
KeyListener and MouseListener and just override keyPressed and mouseClicked.
Some basic grepping yields the following list:
ComponentListener
ContainerListener
DragSourceListener
DropTargetListener
FocusListener
HierarchyBoundsListener
InternalFrameListener
KeyListener
MouseListener
MouseMotionListener
PrintJobListener
WindowListener
best regards,
Andreas Lundblad
