SlowHawk wants to provide an asynchronous version of its service to give fare information. One asynchronous message requests fare information, and a second asynchronous message provides the fare information. Design WSDL specifications for these two services, and then design a BPEL specification for the business process consisting of these two services.

What will be an ideal response?

For simplicity we will assume that SlowHawk’s only client is GoSlow. Hence, when an asynchronous request for fare information arrives, SlowHawk knows to whom to reply. It does this using a callback port type provided by GoSlow. Let GoSlow’s port type be named asynchRespPT and its (one-way) operation asynchRespOp.
SlowHawk’s asynchronous service will be hosted at a new port type:

A newpartner link type to connect the two processes through the newport types is required.

SlowHawk must then declare (in its BPEL program) a partner link which asserts its role in the message exchange.






partnerLinkType=‘‘gs:asynchGetFarePLT’’

myRole=‘‘airline’’ partnerRole=‘‘travelAg’’/>

Finally, the receive/reply pattern of communication used for synchronous requests in SlowHawk is replaced by a receive to accept the request from GoSlow and an invoke to return the reply.




portType=‘‘asynchGetFarePT’’

operation=‘‘asynchGetFareOp’’ variable=‘‘asynchGetFareVar’’/>




portType=‘‘asynchRespPT’’

operation=‘‘asynchRespOp’’ inputVariable=‘‘asynchRespVar’’/>