Syntax
SET-CALLBACK ( callback-name , routine-name [ , routine-context ] )
|
-
callback-name
- A quoted string or character expression representing the name of a
callback. The callback-name is not case-sensitive.
- For a ProDataSet buffer object handle, this can be "BEFORE-FILL", "AFTER-FILL", "BEFORE-ROW-FILL",
"AFTER-ROW-FILL", "ROW-CREATE", "ROW-DELETE", "ROW-UPDATE", "FIND-FAILED", or "SYNCHRONIZE".
- For a Procedure object handle, when calling a Web service, this
can be either "REQUEST-HEADER" or
"RESPONSE-HEADER".
- For a ProDataSet object handle, this can be "BEFORE-FILL" or "AFTER-FILL".
- For a Query object handle, this can be "OFF-END".
You can also use the APPLY-CALLBACK( ) method to apply a callback
procedure for an object.
-
routine-name
- A quoted string or character expression representing the name of a
method or an internal procedure that resides within routine-context. If calling this on a procedure handle, routine-name can only be an internal procedure.
-
routine-context
- An object reference for a class instance or a handle to a persistent procedure
that contains the method or internal procedure specified by routine-name.
If not specified, and the routine is executed within a procedure,
THIS-PROCEDURE is used as the routine context. If not specified,
and the routine is executed within a class instance, THIS-OBJECT
is used as the routine context.
If callback-name is not a valid
callback, or routine-context is not a valid object
reference or handle, this method returns FALSE; otherwise, it returns TRUE. If the
SET-CALLBACK( ) method is specified but cannot be invoked, or it fails, no method or
procedure is executed as part of the callback event.
Notes
- If routine-name represents
a class method that is associated with an ABL event as a callback,
and the method is overridden in a derived class, the overridden
method is run when the callback is invoked.
- To clear a callback, pass the Unknown (?) value or an empty string as
the routine-name parameter. The following code fragment shows clearing
a callback by passing the empty string:
| BUFFER <buffer-name>:HANDLE:SET-CALLBACK ("After-Row-Fill", "").
|
- When used with a class instance, the SET-CALLBACK( ) method creates an
internal reference to the instance. As a result, the instance cannot be garbage collected
while the callback is in effect. If you clear it, the object may be garbage collected if
there are no more references to it.
- For more information on specifying SOAP header callback methods at run time see OpenEdge Development: Web Services.
