Design And Realization Of SCA-Based Lightweight BPEL Engine

SOA is becoming a more and more important concept of software engineering area, which will become the direction and reference for software engineering procedure. However, how to use the concept of SOA in software engineering in a normative way has been a focused question for a long time. There are some functions coming out during these years to use SOA, including BPEL and SCA, which are two important functions in this area.Business Process Execution Language (BPEL) is an XML-based language for creating a workflow process, which became an important way to implement the concept of SOA since being brought forward. BPEL gives out a new idea to reuse and reorganize the existing systems which were produced based on different architectures and different languages. BPEL was created specially to arrange Web Services for a new workflow, which could effectively improve the reusability of the existing systems.Service Component Architecture (SCA) is a proposed standard for composing and deploying SOA. When SCA-compliant products are in place at development and run time, one could write code in the implementation language of any choice, but with an important difference than the focus is on business logic but not language any more. SCA allows to avoiding writing many of the technology-specific details, especially the transfer protocol.Based on the introductions and advantages of BPEL and SCA, this article gives out a new design of a SCA-based lightweight BPEL engine. This article firstly introduces the relationship between BPEL and BPEL engine, and the design direction of the lightweight engine. And then specially designs and analyses the architecture of the lightweight engine, also introduces the essential of the concept of lightweight. Based on the design of architecture, this article introduces the function design for every module of the engine in detail with some diagrams and core codes. At last, this article introduces one example to use the SCA-based lightweight BPEL engine in a hospital system.This article gives out an idea to bind BPEL engine together with SCA in a new way, which means adopting the way that SCA composing and deploying SOA as reference in the design of the lightweight BPEL engine. Besides that, this article also gives out a delamination model for BPEL, which could be used for mapping the elementes of BPEL to database tables directly.