ATk, Java and Change Notifications

["Padraig O'Briain" <Padraig Obriain Sun COM>]

The Java class AccessibleContext has a number of constants which are used to 
indicate that something has changed. This note identifies those constants
and states how they are currently implemented, if at all, in ATK.

There is currently no implementation in ATK for the following:

ACCESSIBLE_ACTION_PROPERTY
ACCESSIBLE_ACTIVE_DESCENDANT_PROPERTY
ACCESSIBLE_SELECTION_PROPERTY
ACCESSIBLE_TABLE_CAPTION_CHANGED
ACCESSIBLE_TABLE_COLUMN_DESCRIPTION_CHANGED
ACCESSIBLE_TABLE_COLUMN_HEADER_CHANGED
ACCESSIBLE_TABLE_MODEL_CHANGED
ACCESSIBLE_TABLE_ROW_DESCRIPTION_CHANGED
ACCESSIBLE_TABLE_ROW_HEADER_CHANGED
ACCESSIBLE_TABLE_SUMMARY_CHANGED
ACCESSIBLE_VALUE_PROPERTY
ACCESSIBLE_VISIBLE_DATA_PROPERTY


Proposals for ATK implementations will follow.


ACCESSIBLE_ACTION_PROPERTY

Constant used to indicate that the supported set of actions has changed.

I have not found any Java code which uses this and there is no corresponding
implementation in ATK.


ACCESSIBLE_ACTIVE_DESCENDANT_PROPERTY

Constant used to determine when the active descendant of a component has 
changed.

In Java, this is fired when the lead selection index for a JList, the
lead selection path for a JTree, and the last selected row and column for
a JTable has changed.

Currently we do not have an implementation for this in ATK.


ACCESSIBLE_CARET_CHANGED

Constant used to determine when the accessibleText caret has changed.

In ATK we have a signal "text-caret-moved" which is emitted when the caret
position has changed.


ACCESSIBLE_CHILD_PROPERTY

Constant used to determine when Accessible children are added/removed from 
the object.

In ATK, a property called "accessible-child" is defined and a notify signal
is emitted for that property when a child is added or removed.


ACCESSIBLE_DESCRIPTION_PROPERTY

Constant used to determine when the accessibleDescription property has changed.

In ATK, a property called "accessible-description" is defined and a notify 
signal is emitted for that property when the desciption is changed.


ACCESSIBLE_NAME_PROPERTY

Constant used to determine when the accessibleName property has changed.

In ATK, a property called "accessible-name" is defined and a notify 
signal is emitted for that property when the name is changed.


ACCESSIBLE_SELECTION_PROPERTY

Constant used to determine when the accessibleSelection has changed.


ACCESSIBLE_STATE_PROPERTY

Constant used to determine when the accessibleStateSet property has changed.

In ATK, a property called "accessible-state" is defined and a notify 
signal is emitted for that property when the name is changed. For this
property only, the old and new values reported by the ATK property change 
handler are meaningful, with an old value meaning that a state has been 
switched off and a new value meaning that a state has been switched on.


ACCESSIBLE_TABLE_CAPTION_CHANGED

Constant used to indicate that the table caption has changed The old value 
in the PropertyChangeEvent will be an Accessible representing the previous
table caption and the new value will be an Accessible representing the new 
table caption.


ACCESSIBLE_TABLE_COLUMN_DESCRIPTION_CHANGED

Constant used to indicate that the column description has changed The old 
value in the PropertyChangeEvent will be null and the new value will be an
Integer representing the column index.


ACCESSIBLE_TABLE_COLUMN_HEADER_CHANGED

Constant used to indicate that the column header has changed The old value 
in the PropertyChangeEvent will be null and the new value will be an
AccessibleTableModelChange representing the header change.


ACCESSIBLE_TABLE_MODEL_CHANGED

Constant used to indicate that table data has changed.


ACCESSIBLE_TABLE_ROW_DESCRIPTION_CHANGED

Constant used to indicate that the row description has changed The old 
value in the PropertyChangeEvent will be null and the new value will be 
an Integer representing the row index.


ACCESSIBLE_TABLE_ROW_HEADER_CHANGED

Constant used to indicate that the row header has changed The old value 
in the PropertyChangeEvent will be null and the new value will be an
AccessibleTableModelChange representing the header change.


ACCESSIBLE_TABLE_SUMMARY_CHANGED

Constant used to indicate that the table summary has changed The old value 
in the PropertyChangeEvent will be an Accessible representing the previous
table summary and the new value will be an Accessible representing the new 
table summary.


ACCESSIBLE_TEXT_PROPERTY

Constant used to determine when the accessibleText has changed.

In ATK a signal "text-changed" is defined and this signal is emitted when the
text has changed.


ACCESSIBLE_VALUE_PROPERTY

Constant used to determine when the accessibleValue property has changed.


ACCESSIBLE_VISIBLE_DATA_PROPERTY

Constant used to determine when the visual appearance of the object has 
changed.



Padraig