我如何获得潜在的静态数组了在Java的CopyOnWriteArrayList的？ [英] How do I get the underlying static array out of a CopyOnWriteArrayList in Java?

问题描述

我有保留的类的功能列表的类。这些特性的变化很少相比读取。在读取几乎都是通过功能列表迭代。正因为如此，我使用的CopyOnWriteArrayList 。

I have a class which maintains a list of features of the class. These features change infrequently compared to the reads. The reads are almost always iterations through the feature list. Because of this, I'm using a CopyOnWriteArrayList.

我想有这样的功能：

function Feature[] getFeatures() {
  .. implementation goes here ..
}

我承认，其原因可能有点懒惰。我想写code是这样的：

I admit, the reason may be a bit of laziness. I'd like to write code like this:

for (Feature f: object.getFeatures()) {
  .. do something interesting ..
}

而不是这样的：

Iterator<Feature> iter = object.getFeatureIterator();
while (iter.hasNext()) {
  Feature f = iter.next();
  .. do something interesting ..
}

主要的问题是 - 我在偷懒吗？我会遵循这个模式有很多，我想code的第一大块是更容易维护。很显然，我永远不会改变底层的数组，我会把这个文档中

The main question is - am I being lazy here? I'm going to follow this pattern a lot, and I think the first chunk of code is far easier to maintain. Obviously, I would never change the underlying array, and I would put this in the documentation.

什么是处理这种情况的正确方法？

What is the proper way to handle this situation?

推荐答案

只要打电话给方法的toArray名单上：

Just call the toArray method on the list:

public Feature[] getFeatures() {
    return this.featureList.toArray(new Feature[this.featureList.size()]);
}

注意的foreach语法可以与所有了Iterable对象使用和列表是可迭代，所以你可以只是

Note that the foreach syntax can be used with all the Iterable objects, and List is Iterable, so you could just have

public List<Feature> getFeatures() {
    return this.features;
}

和使用相同的foreach循环。如果你不希望调用者修改的内部列表，返回列表的不可修改视图：

and use the same foreach loop. If you don't want the callers to modify the internal list, return an unmodifiable view of the list:

public List<Feature> getFeatures() {
    return Collections.unmodifiableList(this.features);
}

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