ServiceTechMag.com > Issue XXX: July 2009

Issue XXX July 2009

The Service Engine:
Structured Communication using Modern Service Technologies

Paul S Prueitt

Paul S Prueitt

A simple stand-alone fixed finite state machine may be used as an engine that determines all triggers for a particular set of web services. Such an engine requires a uniform design regime over all service contracts [REF-1]. This type of machine may exist as a URI/URL web service provider. The community of such providers defines a network infrastructure for social networks engaged in common tasks. Within this infrastructure, services may be offered and fulfilled using a structured method for machine specification [REF-2] (SMMS). Data persistence is distributed in a peer-to-peer architecture, again very simple in nature. XML files with very simple XML schema [REF-3] are all that is necessary and may be passed around the web using HTTP requests. The files may be manufactured in AJAX, SOAP or REST architectures. XML/XML-schema may also be manufactured using a hash table. Persistence may then be in the cloud with a minimal repository. So what will a service engine do? It will model context using direct input from everyday use. In essence there is a separation of particular instances, as experienced by the individual, from the composition of universals forming the common basis for human communication. As such it supports social network infrastructure through the provision of a knowledge management type community enumerated framework. The framework might be a Zachman [REF-4] or Sowa [REF-5] framework, or one of a general class of...


Service Error Content Patterns - Part I

Ronald Murphy

Ronald Murphy

Exceptions are a necessary evil in the world of service development and one that must be controlled and planned for. Allowing exceptions just to happen can have numerous negative consequences, especially when relying upon some of the more common fault handling options made available to us with current Web-based technologies. In this two-part article series we'll explore several successful techniques for controlling runtime error conditions and ensuring that their occurrence does not unnecessarily (or chaotically) disrupt the business process flow. The techniques form actual development patterns that can be applied to different types of services based on different types of service technologies. The name of SOAP's earlier cousin, XML-RPC, nicely captures the dual nature of SOAP itself: in one sense, this Web service technology is focused on XML and document exchange (via the document-literal binding), and in another sense it is a remote programming mechanism (via the RPC binding). Nowhere is this duality more evident than in error modeling. Are errors just a kind of data to be carried in our document-like responses, or are they part of the procedural control flow? Looking just at the SOAP standard alone, we seem to have an easy answer: Errors should be expressed as SOAP faults. But a look into the history of programming reveals a more complicated situation with a variety of trade-offs, as we'll examine in this article. XML-RPC and SOAP arrived at the crest of an era of very large scale programming - the 1990's...


An SOA Case Study:
Integrating Adobe LiveCycle Forms using JBossWS

Rizwan Ahmed

Rizwan Ahmed

JBossWS is a framework which implements the JAX-WS 2.0 (a replacement for the earlier JAX-RPC) specification and defines the programming/runtime model for implementing web services as a remoting mechanism for distributed service-oriented architectures [REF-1]. JBossWS is targeted at the Java SE 6/EE 5 platform and integrates with most current and earlier JBoss Application Server releases. In this article, I demonstrate how easy it is to use the JBossWS framework to harness the power of Java 5 annotations as well as endpoint associated metadata provided by JSR 181 annotations to develop, provide, consume and secure a service. The annotations ensure that the source code will be fairly simple and straightforward POJOs with the onus of processing falling to JBossWS tools at the client and server to create the contract and infrastructure plumbing needed at deployment and runtime. In order to illustrate the concepts, I have used the example of a real life service that allows different systems within our organization (a State Government Agency) to integrate with a centralized Forms system to retrieve, deliver and process intelligent documents to and from end users. As an integral part of daily operations, our agency needs to manage hundreds of different forms in various business functional areas - from customer enrollment and benefit applications to federal tax and compliance reporting. The Adobe LiveCycle® Forms software allows us to create and deploy XML based form templates rendered as PDF and HTML at runtime for use with the Adobe Reader® software or...


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