Web services creation made easy

BEA Systems Inc.’s WebLogic Workshop is a combination development/run-time environment, very much in the spirit of IBM Corp.’s WebSphere Application Developer. But WebLogic Workshop exclusively generates J2EE applications, and it operates at a dizzying level of abstraction compared with similar tools. Whereas J2EE was all about abstracting low-level entities such as database rows and message queues, WebLogic Workshop is all about abstracting J2EE.

The premise is sound. The density of J2EE APIs is daunting, so why not make a tool that allows the developer to concentrate on request/response conversation content, database access, and business logic, then let the tool worry about conversation structure and protocol, EJB deployment descriptor syntax, the ocean of API method calls, and so on? Such is the aspiration of WebLogic Workshop.

It succeeds reasonably well. I found I could build a complete J2EE application without once making face-to-face contact with an EJB or a servlet. The Workshop allowed me to work on the inside – where everything important was happening – while it took care of the outside, the interfaces, and the connections. It was a relief to create a J2EE application without having to enter the maze of J2EE documentation.

Zeroing in on Web services

WebLogic Workshop focuses its capabilities on the creation of Web services and Web services clients. The Workshop includes a development-server version of the WebLogic application server, so services and clients can be tested virtually the instant they’re created. The Workshop includes a kind of test-bed browser that allows you to exercise a service even before a client has been built.

The Workshop’s power derives from two bits of magic: one conjured in the development phase, the other at execution time. In the development phase, the magic is Javadoc annotations – formalized comments that season IDE (integrated development environment)-generated source code. These annotations are read by the run-time framework prior to application deployment and guide the instantiation of infrastructure plumbing in the form of EJBs (plus an incidental servlet) that support all the nonbusiness-logic behavior of a Web service. This instantiation occurs only when you’re developing and testing from within the Workshop. You must perform a separate, explicit compilation to create an EAR (Enterprise ARchive) for deploying on a production server.

At execution, the magic is the Java Workshop’s run-time framework, a container riding atop WebLogic application server and hosting infrastructure EJBs. Each EJB is responsible for a specific set of Web service support activities. These infrastructure beans are assisted by a servlet and a message-driven bean, the former accepting HTTP requests for Web services and the latter accepting requests on incoming JMS (Java Message Service) message queues. At all times, the developer is blissfully unaware of this engine running under the hood.

The XML lifeblood

SOAP is the lifeblood of a Workshop Web service, and XML forms its corpuscles. All interactions between components of a Workshop-built J2EE application, as well as between clients and services, communicate via XML wrapped in SOAP. At multiple points of execution, therefore, your code must read and write XML messages. The Workshop provides two tools for this: the XQuery mapper and XMLBeans.

The XQuery mapper reads an XML schema on one side, an input method to a Web service control on the other side, and allows you to graphically connect the two. A developer can literally drag connecting lines from nodes of a parsed XML schema view on one side and connect them to Java object members on the other. The Workshop does the rest; at run time, XML messages will be unpacked and their contents delivered to the proper object members.

XMLBeans take a more procedural approach. The Workshop reads the schema, and produces a bean whose methods allow your application to read, write, and modify XML message elements. All the while, the XMLBean maintains the fidelity of the XML message itself.

But when developing with BEA’s WebLogic Workshop, are you creating a J2EE application? No and yes.

No, in that you deal with abstractions of activities, rarely touching J2EE directly. When using Workshop, the only direct exposure I had to J2EE denizens were the JSPs that comprised the presentation portion of the Web service.

The answer is also yes, in that the Web service that finally executes is a J2EE application. It’s made up of servlets and JSPs and EJBs and JMS queues, all calling standard J2EE APIs. They’re there, but you’d hardly know it.

Sidebar box:

The Bottom Line

Summary: BEA WebLogic Workshop 8.1 is a unique development environment for creating J2EE Web services that run atop the WebLogic application server. The developer does little interacting with J2EE itself, so you need only a moderate to advanced understanding of Java and very little understanding of J2EE.

Platform(s): BEA WebLogic Workshop 8.1 is available in the Application Developer Edition and provides the basic development, testing, and deployment tools described here. The Platform Edition adds capabilities for developing portal applications and is designed to be used in conjunction with BEA’s WebLogic Portal 8.1 and WebLogic Integration 8.1

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