外文翻译-对象技术

Object Technology

Object technology is a new approach to developing software that allows programmers to create objects, a combination of data and program instructions. This new technology has been steadily developed since the late 1960s and promises to be one of the major ingredients in the response to the ongoing software crisis.

1. 1 Introduction to 0T

There exists a critical technology that is changing the way we conceive, build, use and evolve our computer systems. It is a technology that many companies are adopting to increase their efficiency, reduce costs and adapt to a dynamic marketplace. It is called Object Technology (0T)・

By allowing the integration of di spar a te and non compa ti ble source, 0T has the potential to precipitate a revolution in information systems design on a par with that caused in computer hardware by the introduction of the computer chip. Yet 0T is not a new phenomenon. Development and product releases have been ongoing since its origin many years ago. However, the recent emphasis task of enterprise information technology integration has brought 0T into the spotlight・

0T promises to provide component-level software objects that can be quickly combined to build new applications that respond to changing business conditions. Once used, objects may be reused in other applications, lowering development costs and speeding up the development process. Because objects communicate by sending messages that can be understood by other objects, large integrated systems are easier to assemble.

Each object is responsible for a specific function within either an application or a distributed system. That means that as the business changes, individual object may be easily upgraded, augmented or replaced, leaving the rest of the system untouched. This directly reduces the cost of maintenance and the timing and extendibility of new systems. 1・ 2 OT-based Products

The current market for OT-based products can be divided into four major segmen:ts

Lan guages and program ming tools

•Developers' tooikits

•Object-Orie nted "tabase

•Object-Orie nted CASE tools

The largest segment of the current market for 0T~based products is languages and programming tools. Products in this area include language compilers for C++， SmalItalk, Common Lisp Object System (CLOS), Eiffel, Ada and Objective~C, as well as extensions to PASCAL and Modula-2・

Products in this category are available from a variety of vendors. Increasingly, the trend in this group is to offer the language compilers with associated development tools

as part of a complete development environment・

Developers^ toolkits account for the next largest part of the OT market・ These products are designed to develop a program that enables a developer to easily do one of two things. The first is interfacing an application to distributed environment. The second is developing a graphical screen through a product.

By providing developers with higher level description language and reusable components, products in this category give developers an easy and cost effective way to begin producing object-oriented systems.

An important component in this category is the relatively new area of end~users tools. This element is important because organizing and analying the increasingly large amounts

of data that computer systems are capable of collecting is a key problem.

Object-oriented database management systems are oonfethe most interesting and rapidly growing segments of the OT market. A number of companies, including systems vendors like Digital and HP, and start一ups such as Object Design, Servio, and Objectivity, have all produced products.

These products, dubbed" Objectbases" , fill an important need by storing complex objects as a single entity. The objectbase products allow objects to be stored, retrieved and shared in much the same way as data is stored in a relational database management system.

The value of an objectbase, as opposed to a database, is best described as following：

u Object databases offer a better way to store objects because they provide all of the