SET-CALLBACK-PROCEDURE( ) method

Associates an internal procedure with an ABL callback event.

Return type:

LOGICAL

Applies to:

Buffer object handle, Procedure object handle, ProDataSet object handle, Query object handle

 

Syntax 

SET-CALLBACK-PROCEDURE ( callback-name ,internal-procedure               [ , procedure-context ] )

callback-name

A quoted string or character expression representing the name of a callback. The callback-name is not case-sensitive. For example:

For Web services, this can be either "REQUEST-HEADER" or "RESPONSE-HEADER". The AVM invokes the internal procedure associated with the "REQUEST HEADER" event as part of an outgoing SOAP request. The request procedure provides access to the SOAP header during the request message. The AVM invokes the internal procedure associated with the "RESPONSE HEADER" callback as part of an incoming SOAP request. The response procedure provides access to the SOAP header during the response message.

For a ProDataSet object, this can be "BEFORE-FILL" or "AFTER-FILL".

For a ProDataSet object buffer, 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 query, this can be "OFF-END".

You can also use the APPLY-CALLBACK( ) method to apply a callback procedure for an object.

internal-procedure

A quoted string or character expression representing the name of an internal procedure that resides within procedure-context.

For Web services, the AVM invokes the specified internal procedure as part of the SOAP request message formulation.

procedure-context

A handle to a procedure that contains the internal procedure specified by internal-procedure. If not specified, THIS-PROCEDURE is used as the procedure context.

This method returns FALSE if the callback-name is not valid or if procedure-context is not a valid handle; returns TRUE otherwise. If this method is specified but cannot be invoked, or it fails, no procedure will be executed as part of the callback event.

If this method is called multiple times, the new values passed replace the previously set values.

To remove the callback procedure associated with a Web service procedure, invoke this method with a valid callback-name and an empty string, "", for the internal-procedure. The AVM will not generate an error if an attempt is made to remove a callback procedure and a callback is not associated with the callback.

For more information on events, see the “Handle-based Object Events Reference” section.

See also:

APPLY-CALLBACK( ) method, GET-CALLBACK-PROC-CONTEXT( ) method, GET-CALLBACK-PROC-NAME( ) method