Chapter 14: Deploying Web Services and CORBA Interoperation


Overview

The Geronimo server is quite versatile and can work with a large variety of access technologies. For example, users who are using Web browsers can access Web applications running on Geronimo, and thin-client applications can tap into the rich services provided by components (such as EJBs) running on Geronimo’s business tier. Recently, the ubiquity in using the Internet as the interconnection between businesses had made Web services technology extremely popular. The idea of Web services is to combine standards-based XML messages with the use of standard Internet transport protocols to deliver a robust service access and interoperation mechanism. Web services provide a platform for business-to-business and business-to-customer exchange of data and services over the Internet. The standards-based nature of Web services enable the software on both sides of the communication channel to be built with potentially different hardware systems and software.

Geronimo has built-in support of the deployment of Web services. With Geronimo, you can do the following:

  • Expose EJBs as Web services

  • Create and deploy J2EE-compliant, JAX-RPC-accessible Web services

  • Consume Web services from your Web-tier or business-tier components

In this chapter, you will discover how to configure Geronimo to expose an EJB as a Web service and how to deploy a component that supports JAX-RPC-based Web service access. Consuming Web services from a software component is primarily a development concern (utilizing the library support provided by Geronimo) and is outside the scope of this chapter.

While support of Web services open up Geronimo to a brave new world of access by diverse Web services clients, the Common Object Request Broker Architecture (CORBA) standard enables a Geronimo server to interoperate with a large universe of legacy systems and applications.

CORBA is a specification created by the Object Management Group (OMG), and has been established to enable software components created in different programming language, running on different operating systems, hosted on different hardware platforms to communicate and do useful work with one another. This goal of CORBA is somewhat similar to the goal of Web services. The differentiator is mainly in the audience that each technology addresses. Web services has a general audience, is based on standard Internet transport protocols and standard XML message formats. CORBA’s main focus is on users with existing legacy systems such as mainframe, minicomputer, real-time mission-critical systems, or super-computers. CORBA is based on an OMG-specified transport protocol passing binary formatted messages.

The Geronimo server is capable of the following:

  • Exposing an EJB as CORBA component, to be accessed by any CORBA client

  • Providing access to external CORBA systems and components

The second capability is a development issue and out of the scope of this chapter.

The chapter reveals how to configure and deploy an EJB using a Geronimo server that can be accessed as a CORBA component. This coverage includes a discussion of the CSIv2 security mechanism used by CORBA systems and how to configure secured access when using CORBA components.




Professional Apache Geronimo
Professional Apache Geronimo (Wrox Professional Guides)
ISBN: 0471785431
EAN: 2147483647
Year: 2004
Pages: 148

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