- No reusability. The least interesting of all. It’s typically a standalone application that was designed to serve a finite set of goals and not be extensible by anybody else but its creator.
- Binary reusability. While the source is not available, binary reusability enables third parties to write extensions to the software. Microsoft COM is the best example of such an approach, and it’s been tremendously successful. For example, even though you don’t have access to Internet Explorer’s HTML renderer, you can still embed it in your applications and take advantage of all its power (Yahoo Messenger uses it but you would probably never tell).
- Plug-in reusability. This is very similar to the binary approach mentioned above but with the difference that the operating system is not involved in the connection between the plug-in and the core architecture. Eclipse is a good example of such an approach, which can also be used in the absence of the source.
- Source reusability. The software is shipped with its entire source code, making it possible — in theory — for everyone to extend it at will.
结果是： 1 小于 4 小于 3 小于 2
您是否这样认为
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| 日期: | 04-12-23 12:49 | |
