Within the workbench a plugin may extend the actions which appear in the
context menu for any object. The visibility of each action extension is
controlled by action filtering. By default, the workbench will filter each
action extension using the
objectClass and optional
nameFilter attributes defined in xml. If the action extension
passes this test the action will be added to the context menu for the object.
In some situations the object class and name are not enough to describe the
intended target action. In those situations an action extension may define
one or more
filter sub-elements. Each one of these elements
describes one attribute of the action target using a
pair. The attributes for an object are type specific and beyond the domain of
the workbench itself, so the workbench will delegate filtering at this level
IActionFilter. This is a filtering strategy which is
provided by the selection itself and may perform type specific filtering.
The workbench will retrieve the filter from the selected object by testing to
see if it implements
IActionFilter. If that fails, the workbench
will ask for a filter through through the
If a filter is found the workbench will pass each name value pair to the
filter to determine if it matches the state of the selected object. If so, or
there is no filter, the action will be added to the context menu for the
Clients that implement this filter mechanism are strongly encouraged to extend this interface to provide a list of attribute names and possible values that are considered public for other clients to reference.
- See Also:
testAttributeReturns whether the specific attribute matches the state of the target object.
target- the target object
name- the attribute name
value- the attribute value
trueif the attribute matches;