Home arrow Web Services arrow Page 3 - Flow and Web Services
WEB SERVICES

Flow and Web Services


Last week, we looked at process lifecycles. This week, we'll take a look at the assign and other basic activities, and study flow. This article, the fourth in a series, is excerpted from chapter 12 of Building Web Services with Java: Making sense of XML, SOAP, WSDL, and UDDI, written by Steve Graham et al. (Sams; ISBN: 0672326418).

Author Info:
By: Sams Publishing
Rating: 4 stars4 stars4 stars4 stars4 stars / 5
August 24, 2006
TABLE OF CONTENTS:
  1. · Flow and Web Services
  2. · XPath Extension Functions
  3. · Flows
  4. · Link Semantics
  5. · Putting Together the Flow Sample

print this article
SEARCH DEVARTICLES

Flow and Web Services - Flows
(Page 3 of 5 )

Graph-oriented constructs are a common approach for controlling the flow of execution of several activities. The BPEL flow activity lets you define a collection of activities, parts of which may be performed in parallel. Activities in a flow can be wired together via links that specify the execution order between activities, including the synchronization of parallel execution branches within that flow. Furthermore, transition conditions determine the branches of a flow to be navigated, and join conditions specify requirements about parallel branches joining at an activity; they need to be fulfilled to execute that activity.

In SkatesTown's purchase order process, a flow activity controls the main processing of the purchase order, starting with its validation and finishing with the creation of the invoice and the initiation of the order's delivery:

  • Some activities of this flow must be performed before others, for example, validation needs to happen first.

  • Some activities can be executed in parallel, such as the creation of the invoice and the initiation of the delivery.

  • The flow also uses transition conditions. For example, based on the result of the validatePurchaseOrder activity, processing of the order either continues normally or is discontinued by throwing the fault invalidPO.

Figure 12.5 outlines the graph of this flow; its activities are represented as nodes, and its links as edges.


blog comments powered by Disqus
WEB SERVICES ARTICLES

- Dealing with Loose Coupling in a Service-Ori...
- Loose Coupling in a Service-Oriented Archite...
- Safety, Idempotence, and the Resource-Orient...
- The Resource-Oriented Architecture in Action
- Features of the Resource-Oriented Architectu...
- The Resource-Oriented Architecture
- Getting Started with Flex
- Automated Billing and Faxing for the Web
- An Introduction to Web Services
- The Foundations of Web Services: From Novice...
- Web Services Reengineering: Finishing Touches
- Fault Handling with Web Services
- Flow and Web Services
- Process Lifecycles and Web Services
- Business Processes and Web Services

Watch our Tech Videos 
Dev Articles Forums 
 RSS  Articles
 RSS  Forums
 RSS  All Feeds
Write For Us 
Weekly Newsletter
 
Developer Updates  
Free Website Content 
Contact Us 
Site Map 
Privacy Policy 
Support 

Developer Shed Affiliates

 




© 2003-2017 by Developer Shed. All rights reserved. DS Cluster - Follow our Sitemap
Popular Web Development Topics
All Web Development Tutorials