ArrayList< X>聚集或组成? [英] Is ArrayList<X> an aggregation or composition?

问题描述

我正在为编程考试做准备，并遇到了这个问题，我知道在汇总对象时是借用的，而在构成时对象是拥有的.答案组成了吗?

I am preparing for my programming exam and came across this question, I know that in aggregation the object is borrowed, and in composition the object is owned. Is the answer composition?

ArrayList< X> 是 X 的集合还是 X 的组成?

Is an ArrayList<X> an aggregation of X or composition of X?

ArrayList<Point> pts = new ArrayList<Point>();
Point p = new Point(0., 0., 0.);
pts.add(p);
p.setX( 10.0 );
System.out.println(p);
System.out.println(pts.get(0));

推荐答案

来自此处:

简单规则:

1. A是拥有的" B =组成:在没有A的系统中，B没有任何意义或目的.
2. A使用" B =聚集:B与A独立(概念上)存在

因此，它实际上取决于您的模型.列表中的元素可以不存在列表而存在.是否必须将元素放入列表中才有意义?

Therefore, it really depends on your model. Can the elements in the list, exist without the list. Does the elements have to be put into the list to be meaningful?

对于 ArrayList< Point> ，我认为这是一个聚合.

In the case of ArrayList<Point>, I think it is an aggregation.

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