The SenderFramework can invoke handlers at two stages during the sender processing flow: preprocessing and postprocessing. These stages are also referred to as configuration points. Preprocessing refers to what occurs before the request document is given to the sender to be sent to its destination and postprocessing occurs after the request document has been sent to its destination and the SenderResult object has been created to document the request's status.
WebSphere Partner Gateway ships with a number of predefined handlers, but you can also develop your own, if you have specific needs not satisfied by the delivered handlers. If a request document comes from a preferred trading partner, for example, a custom preprocessing handler can be written to determine the partner's status and set the transport headers accordingly. After the handlers are written and deployed, you need to configure them by using the Community Console, just as you configure handlers supplied by WebSphere Partner Gateway. For further information on this process, see the Hub Configuration Guide.