1. Slide 1 Asynchronous Composition Pyounguk Cho, Oracle Corporation

2. Slide 2 Agenda Synchronous Composition Asynchronous Composition Demo Q & A

3. Slide 3 Synchronous MEP Definitions Service-centric : Request and response messages get sent over the same transport channel Client-centric : Client thread will be blocked until send() returns

4. Slide 4 Synchronous Services Common use cases Request/response MEP over HTTP Short-running operations Real-time processing What are the pain points? Blocking Indefinite waiting Timeout Less scalable due to choking/throttling

5. Slide 5 Asynchronous MEP Definitions Service-centric : Response messages get sent over a different transport channel from the one used for request messages Client-centric : Client thread will not be blocked by invocation

6. Slide 6 Pseudo-Asynchronous Client Primarily to support non-blocking invocation of synchronous services Examples : XMLHTTPRequest object for AJAX applications callback handler function JAX-WS asynchronous client callback handler Blocking/non-blocking polling(local) Client Application Service Provider ClientProxy Synchronous Service

7. Slide 7 Asynchronous Services Common use cases Two one-way MEP over HTTP Long-running operations Delayed or batch processing Fundamental benefits Better suit real-world business model Better overcome transport-level constraints Provide richer messaging patterns beyond request/reply Asynchronous Client Application Service Provider Client ProxyService Callback Service Callback Client

8. Slide 8 Asynchronous Services(cont) Considerations Message correlation(request-callbacks/responses) Random MessageID Process/SessionID Business data(orderID) Callback service Deployment(firewall,..) Policies Identity propagation Timeout & cancellation Purging expired requests Reentrant cancellation for requests under processing Multiple responses Error/fault handling

9. Slide 9 Asynchronous Composition Enabling technologies(under the hood) Polling Asynchronous transport(JMS, SMTP,..) WS-Addressing Asynchronous composition choices BPEL SCA Standalone web services

10. Slide 10 Demo

11. Slide 11 Q & A