有没有什么办法，使在Java中普通的数组不变？ [英] Is there any way to make an ordinary array immutable in Java?

问题描述

用Google搜索了一下，发现很多code的。但是，任何人给我我想要的。我想打一个普通的数组不可改变的。我想这样的：

Googled for it, found plenty of code. But any of them gave me what I want. I want to make an ordinary array Immutable. I tried this:

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class test {

    public static void main(String[] args) {

        final Integer array[];

        List<Integer> temp = new ArrayList<Integer>();
        temp.add(Integer.valueOf(0));
        temp.add(Integer.valueOf(2));
        temp.add(Integer.valueOf(3));
        temp.add(Integer.valueOf(4));
        List<Integer> immutable = Collections.unmodifiableList(temp);

        array = immutable.toArray(new Integer[immutable.size()]);

        for(int i=0; i<array.length; i++)
            System.out.println(array[i]);

        array[0] = 5;

        for(int i=0; i<array.length; i++)
            System.out.println(array[i]);

    }
}

但它不工作，我可以指定一个5到数组[0] ...有没有什么办法让这阵不变？

But it doesnt work, I CAN assign a 5 into array[0] ... Is there any way to make this array immutable?

推荐答案

如果你想的使用它作为一个数组的，你不能。

If you want to use it as an array, you can't.

您必须为它创建一个包装，让你扔在，比方说，的.set（）异常，但无缠绕量将允许你抛出异常的：

You have to create a wrapper for it, so that you throw an exception on, say, .set(), but no amount of wrapping around will allow you to throw an exception on:

array[0] = somethingElse;

当然，元素的不变性是另一回事完全！

Of course, immutability of elements is another matter entirely!

注意：标准异常抛出了不支持的操作是恰当地命名为 UnsupportedOperationException异常;因为它未被选中，你不需要声明它在你的方法的抛出子句。

NOTE: the standard exception to throw for unsupported operations is aptly named UnsupportedOperationException; as it is unchecked you don't need to declare it in your method's throws clause.

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