BPEL-controlled frontends. A process-based pageflow solution. Ingo Meier SOA Competence Center OPITZ CONSULTING

Transcription

1 BPEL-controlled frontends A process-based pageflow solution Ingo Meier SOA Competence Center 1

2 Agenda Introduction and Motivation Options: User interaction + BPEL A solution proof of concept Pro and contra, summary 2

3 1 Introduction and Motivation 3

4 Introduction A little history Early workflows Chiseled in stone Hard to adapt to changes Control information in two places Sequence of the pages Explicit flow models Hard to keep in sync Changes need to be reflected in both Pageflow MVC Workflow Systems Separation of concerns Easier to change 4

5 Motivation where we want to be Clear separation of view on the process and the process itself Control information only in one place, preferably within the process 5

6 Business Process Execution Language - BPEL BPEL is the Web Services Orchestration standard from OASIS*: An XML-based grammar for describing the logic to orchestrate the interaction between Web Services in a business process April *Organization for the Advancement of Structured Information Standards ( 6

7 BPEL4People BPEL (WS-BPEL 2.0) is designed for completely automated business processes No human interactions considered in specification / standard Whitepaper BPEL4People published by IBM and SAP in 2005: ftp://www6.software.ibm.com/software/developer/library/wsbpel4people.pdf Human interactions defined as an important component of longrunning processes Software vendors offer add-ons for human interactions 7

8 2 Options: User interaction + BPEL 8

9 Client Design Worklist and Pageflow Workflow Pageflow Task 1 Task 2 Task 3 Task 1 Task 2 Task 3 Task 1 Task 2 Task 3 Task 1 Task 2 Task 3 Unrelated Task Pages Task 1 Task 2 Task 3 Related Task Pages Pageflow My To Do s 9

10 Workflow Definition from WfMC: The automation of a business process, in whole or part, during which documents, information or tasks are passed from one participant to another for action, according to a set of procedural rules. Preconditions for using SOA-based workflows are Business process models (BPM) Information services (SOA) User interaction (task management) 10

11 Workflow as a Service WSDL Contract Human Workflow Service Assign Task BPEL Process Task Complete Worklist Update Task (1) assign tasks to a user/role (2) wait for task completion as part of an end to end process flow 11

12 Client Design Worklist and Pageflow Workflow Pageflow Task 1 Task 2 Task 3 Task 1 Task 2 Task 3 Task 1 Task 2 Task 3 Task 1 Task 2 Task 3 Unrelated Task Pages Task 1 Task 2 Task 3 Related Task Pages Pageflow My To Do s 12

13 Pageflow Pageflow applications are designed for interaction with one single user The pageflow application (e. g. web app) Starts the business process Helps the user to supply data to the process Preconditions for using SOA-based pageflows are Business process models (BPM) Information services (SOA) Pageflow application 13

14 Standard approach: Collect data and start process Collect data P P P P P P P Start process Process (without further user interaction) A A A A A A A A Possibly send response 14 14

15 3 A solution proof of concept 15

16 POC: Requirements User interaction without using workflow / worklists Separation of pageflow and application logic Flow logic encoded in the BPEL process only Changes in the pageflow can be realized without web app development skills Reusable UI components Loosely coupled UIs Processes connect and orchestrate UIs Multi-channel capabilities Options: JSF, Java Swing, PDA, UI UI A A A A UI A A 16

17 Target architecture wait wait wait MVC Micro Pageflow Timeout MVC Micro Pageflow Timeout MVC Micro Pageflow Timeout Web Module request response request response request FrontendController / Proxy poll/write Queue end signal Start process asynchronously push and wait UI push and wait A A A A UI A A 17

18 Realized architecture Web Application Communication layer BPEL processes HTML JSF Spring Use case Service Frontend Controller Client Service Frontend Controller Queue Process Order Process Queue 18

19 Communication options for the frontend controller Communication layer BPEL processes Web Application HTML Frontend Controller Local Client Frontend Controller Web Service Client Queue Process Order Process JSF Local call (Java) Web Service Call Spring Use case Service Service Frontend Controller Web Service Layer Queue 19

20 4 Pro and contra Summary 20

21 BPEL-controlled frontend: Pros and cons Process-based application Complete flow-logic defined in BPEL process Complete business logic encapsulated in services Process becomes visible in the IT solution Changes of the process can be realized without changes of the UI Usage of standards Integration of arbitrary services is possible All components offering a Web Service interface Via WSIF: EJB, JCA, JMS, local Java, Technical monitoring using the BPEL-Console Change of UI components implicates high investment Communication overhead in case of simple service calls (BPEL, Controller) Single point of failure (BPEL Engine) 21

22 Possible extensions Business process management initiative EPC, BPMN, UML, Generation of BPEL process fragments from business process models Service portfolio (business and technical) Service Lifecycle Management Common repository for processes and services Business monitoring (BAM) Realtime process controlling Multi-dimensional metrics and reports (cp. BI, DW) 22

23 Summary User interaction and BPEL in general Different options: Workflow and Pageflow BPEL-controlled pageflow A solution for an order process 23

24 Ingo Meier SOA Competence Center GmbH