The Best of Both Worlds: Reusable Software via Unplanned Reuse

自20世纪60年代以来，重用已有的软件工件来开发新的软件工件的想法已经得到了推广，因为它具有降低成本和提高质量的潜力。 经典的软件复用要求我们很好地预测软件系统的未来需求，以便以易于复用的形式将其功能模块化，这就是预期复用。由于我们预测未来的能力并不完美，因此会出现开发人员无法找到满足其需求的模块化、可重用工件的情况。一种常见的工业反应是复制和修改现有工件的片段;这是未预料到的重用。预期和非预期的重用方法都有优点和缺点。 预期重用允许我们创建设计良好、文档记录良好的软件工件，但代价很高，而且不能保证投资能够收回。 意外的重用允许高度的可定制性，但可能导致错误的决策，并且不能保证保留旧系统的重要属性。

Since the 1960s, the idea of reusing pre-existing software artifacts for the development of new software artifacts has been promoted for its potential to reduce costs and improve quality. Classical software reuse demands that we predict well the future needs of software systems in order for their functionality to be modularized in an easily reused form; this is anticipated reuse. Since our ability to predict the future is not perfect, there occur cases where a developer cannot find a modularized, reusable artifact that meets their needs. A common industrial response is to copy-and-modify fragments of existing artifacts; this is unanticipated reuse. Both anticipated and unanticipated reuse approaches have benefits and weaknesses. Anticipated reuse allows us to create well-designed and well-documented software artifacts, but at high cost and without guarantee that the investment will be recouped. Unanticipated reuse permits high customizability, but can lead to poor decisions and without guarantee that important properties from the old system are preserved.