在java中的Collections.checkedList（）调用是什么？ [英] What is the Collections.checkedList() call for in java?

问题描述

我只是想知道 java.util.Collections.checkedList（）实际上是用的。

I just want to know for what java.util.Collections.checkedList() is actually used.

我有一些代码，我知道是返回一个 List< String> ，但它是通过一个链的消息传递呼叫，并作为 java.io.Serializable 返回给我。是checkListList调用好我把我的 Serializable 变成 List< String> ？我知道我可以把它转换为 java.util.List ，但我不想检查每个元素，我不舒服，假设每个元素是一个 String 。

I have some code that I know is returning me a List<String> but it's being passed through a chain of messaging calls and returned to me as a java.io.Serializable. Is that checkedList call good for me to turn my Serializable into a List<String>? I know I can cast it to a java.util.List, but I'd rather not have to check each element and I'm not comfortable with assuming each element is a String.

推荐答案

它部分用作调试工具找到代码插入错误类型的类，如果你看到发生了，但不能弄清楚在哪里。

It is used in part as a debugging tool to find where code inserts a class of the wrong type, in case you see that happening, but can't figure out where.

你可以使用它作为公共的一部分API，它提供了一个集合，你想确保集合没有得到任何错误的类型（如果例如客户端删除泛型）。

You could use it as part of a public API that provides a collection and you want to ensure the collection doesn't get anything in it of the wrong type (if for example the client erases the generics).

在你的情况下，你可以使用它的方式是：

The way you could use it in your case is:

 Collections.checkedList(
      new ArrayList<String>(uncertainList.size()), String.class)
      .addAll(uncertainList);

如果这不会引发异常，那么你就知道你是好的。这不是一个性能优化的代码段，但如果列表内容相当小，应该很好。

If that doesn't throw an exception, then you know you are good. That isn't exactly a performance optimized piece of code, but if the list contents are reasonably small, it should be fine.

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