Comp150CPA: Clouds and Power-Aware Computing
Classroom Exercise 16
Orchestration and Choreography
Spring 2011

group member 1: ____________________________ login: ______________

group member 2: ____________________________ login: ______________

group member 3: ____________________________ login: ______________

group member 4: ____________________________ login: ______________

group member 5: ____________________________ login: ______________

In class we have described both BPEL (orchestration) and WS-CDL (choreography) languages for describing web service interactions. Let's explore these in more detail.

  1. Annotate the following description of a web service interaction with the tags <exchange>...</exchange>, <sequence>...</sequence>, <parallel>...</parallel>, <choice>...</choice>, <assign></assign>, and <workunit>...</workunit>, as a preliminary translation into WS-CDL. Warning: some loops are implicit.
  2. Consider the following WS-BPEL:
    <sequence name="TakeOrder" >
       <receive name="receiveOrder" 
                partnerLink ="Client"
                operation="order"/> <!-- here -->
       <reply name="SendConfirmation" 
                partnerLink ="Client"
                operation="confirm"/> <!-- on client -->
    For this example,
    1. What parts are analogous to WS-CDL exchanges?

    2. What parts are analogous to WS-CDL participants?

    3. Please sketch the structure of an approximately equivalent WS-CDL description.

    4. (Advanced) Is choreography a substitute for orchestration, or an extension? Explain.