并发面向对象中的继承反常现象

如果不考虑继承性,并发性与对象技术的结合是很自然的.继承反常(又称继承异常)现象是继承性和并发性不相容的主要原因之一.现阶段人们对继承反常现象的认识有许多模糊之处,出发点不尽相同,形式化的工作也很少.对不同的subtyping关系考虑其特有的渐增式继承方法有利于把握继承反常现象的实质,也丰富了"在并发面向对象语言中应将inheritance层次和subtyping层次区别对待"这一认识的内涵.在阐述基本观点之后,采用范畴论的术语对相关的概念和定义做了形式化工作.一些观点和结论适用于区分和解释相关工作的出发点和贡献,并对并发面向对象技术中继承性的建模问题有所启示.

Inheritance Anomaly in Concurrent Object Orientation

The combination of concurrency and object orientation is definitely natural except for inheritance. One of the interferences between inheritance and concurrency is inheritance anomaly. Although having been researched extensively, inheritance anomalies are still only vaguely defined and often misunderstood, and no much formal work has been done. A new viewpoint is set forth for understanding inheritance anomalies, in which each subtyping relation has its specific incremental inheritance. Related concepts and definitions are formalized through the language of Category.Some issues are well adapted to distinguish and explin different standpoints about inheritance anomalies,and can serve as guidelines in the modeling of inheritance.