什么是最终的ArrayList的意义吗? [英] what is the sense of final ArrayList?
问题描述
哪些优点/缺点我们可以做的ArrayList(或其他集合),最终得到什么?我还可以添加到ArrayList的新元素,删除元素和更新。但什么是影响使得它的决赛?
但什么是影响使得它最终的?
块引用>这意味着你不能重新绑定变量指向一个不同的集合实例的:
最终名单,LT;整数GT;名单=新的ArrayList<整数GT;();
名单=新的ArrayList<整数GT;(); //由于'名单'是决赛,这将不编译作为一个风格问题,我宣布,我不打算改变,因为大多数引用
最后
。
我还可以添加到ArrayList的新元素,删除元素和更新。
块引用>如果你愿意,你可以通过使用<一prevent插入,删除等href=\"http://docs.oracle.com/javase/6/docs/api/java/util/Collections.html#unmodifiableList%28java.util.List%29\"><$c$c>Collections.unmodifiableList()$c$c>:
最终名单,LT;整数GT;清单= Collections.unmodifiableList(新的ArrayList&LT;整数GT;(...));
Which advantages/disadvantages we can get by making ArrayList (or other Collection) final? I still can add to ArrayList new elements, remove elements and update it. But what is effect making it's final?
解决方案But what is effect making it's final?
This means that you cannot rebind the variable to point to a different collection instance:
final List<Integer> list = new ArrayList<Integer>(); list = new ArrayList<Integer>(); // Since `list' is final, this won't compile
As a matter of style, I declare most references that I don't intend to change as
final
.I still can add to ArrayList new elements, remove elements and update it.
If you wish, you can prevent insertion, removal etc by using
Collections.unmodifiableList()
:final List<Integer> list = Collections.unmodifiableList(new ArrayList<Integer>(...));
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