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This book is written for people interested in adopting, designing, and developing systems using distributed objects. The common object request broker architecture (CORBA) is a consensus standard from industry that has significantly changed how information system development is accomplished for both achieving a distributed object-oriented system, as well as for migration of legacy systems to modern architectures. In writing this book, it is assumed the reader has a general knowledge of computer science or programming.
In the book, all standard CORBA-related specifications and key upcoming specifications are covered. Examples of the usage of CORBAservices are included. Since CORBA is a system-oriented technology, applications of the standards, including architecture, development, and migration approaches, are also covered. An entire chapter is devoted to a case study providing lessons learned from real experience.
Overview of the Contents
Part 1 provides an introduction to the technology and its benefits and the key motivations and impacts of adoption. Part 1 sets the context for CORBA technology, including addressing the key organizational challenges involved in the adoption of CORBA, as well as the essential management guidance to assure successful adoption and exploitation of the technology.
Part 2 provides a useris guide to the CORBA standards. These chapters provide a useful introduction to the standards with examples of their applications. The book covers detailed techniques for the use of the interface definition language (IDL), the CORBA 2 standard, and the CORBAservices. This coverage includes concepts, definitions, and examples. Thenew IDL/JAVA language mapping is introduced. In Part II, the first comprehensive model of CORBA components and CORBAservices is provided. This model and associated examples support rapid understanding of complex OMG standards and their interrelationships.
Part 3 addresses the application of CORBA to the definition and development of information systems. Technical guidance on how to apply the standards to create successful systems is provided. In particular, CORBA applications and lessons learned are covered. CORBA is compared with related technologies that will aid in your product selection and justification. Approaches for defining CORBA-based architecture, interfaces, and software are included. Chapter 10 is a case study of a CORBA-based enterprise migration and the lessons learned in implementation and management of the project.
For readers new to CORBA, the book is intended to be read sequentially. If this book achieves anything, it is expected that the reader will understand IDL, an international standard (ISO DIS 14750) that is quickly becoming the universal notation for application program interfaces. Readers familiar with the CORBA infrastructure should read Chapter 4, covering the CORBAservices. Given the large number of these services, it is rare to encounter anyone with knowledge of them all or even of a significant number. Advanced readers should also read Chapter 7, which sets a context for the definition of CORBA-based software architectures, and Chapters 8 and 9, which define a unique approach for CORBA development and migration.
Relationship of This Book to CORBA Specifications
This book does not replace the CORBA standards documents. Instead, it provides an introduction and guidance to readers and users of the standards. There are several large volumes of CORBA standards, including CORBA, CORBAservices, and CORBAfacilities. Even though CORBA standards are more readable than many other types of standards documents, they are voluminous. In many cases, CORBA standards do not include abstractions and examples that are essential for understanding. Furthermore, the specifications do not deal with the application of CORBA to architecture and development, only to its definition.
The first priority is to provide an insightful summary of the standards. The abstractions and examples should aid the readeris understanding of the technology. The standards chapters do not attempt to address all the needs of knowledgeable CORBA practitioners, only the needs of people who want to learn more about the full range of the technology.
The second priority is to provide guidance on how to use these standards and technologies. The authors have been involved in the technical work and management of CORBA projects since 1991, when the standard was first created. This technology presents some fundamental differences in practices for developers, architects, and managers.
It was learned through reviewing and mentoring numerous CORBA projects that many organizations ignore these essential differences in their use of CORBA. This leads to the creation of systems with brittle architectures and implementations, similar to what was created with precursor technologies. By trial and error, some organizations learn how to use the technology more effectively, but many do not progress much beyond the initial level. A key mission of this book is to shorten the learning curve of those organizations adopting CORBA so that they can adjust the management and technology practices to fully exploit the CORBA technologies. In doing so, they will create and migrate to more-effective information systems.
The CORBA specifications described in this book can be downloaded from the Object Management Groupis Web site: