生成器函数在Java中等效 [英] Generator functions equivalent in Java

问题描述

我想在Java中实现一个 Iterator ，其行为与Python中的以下生成器函数类似：

I would like to implement an Iterator in Java that behaves somewhat like the following generator function in Python:

def iterator(array):
   for x in array:
      if x!= None:
        for y in x:
          if y!= None:
            for z in y:
              if z!= None:
                yield z

java端的x可以是多维数组或某种形式的嵌套集合。我不确定这是如何工作的。想法？

x on the java side can be multi-dimensional array or some form of nested collection. I am not sure how this would work. Ideas?

推荐答案

如果有相同的需要，那么为它写一个小课程。以下是一些示例：

Had the same need so wrote a little class for it. Here are some examples:

Generator<Integer> simpleGenerator = new Generator<Integer>() {
    public void run() throws InterruptedException {
        yield(1);
        // Some logic here...
        yield(2);
    }
};
for (Integer element : simpleGenerator)
    System.out.println(element);
// Prints "1", then "2".

无限发电机也是可能的：

Infinite generators are also possible:

Generator<Integer> infiniteGenerator = new Generator<Integer>() {
    public void run() throws InterruptedException {
        while (true)
            yield(1);
    }
};

生成器类内部使用线程生产这些物品。通过重写 finalize（），它确保如果不再使用相应的Generator，则不会留下任何线程。

The Generator class internally works with a Thread to produce the items. By overriding finalize(), it ensures that no Threads stay around if the corresponding Generator is no longer used.

性能显然不是很好，但也不是太破旧。在具有双核i5 CPU @ 2.67 GHz的机器上，可以在< 0.03s。

The performance is obviously not great but not too shabby either. On my machine with a dual core i5 CPU @ 2.67 GHz, 1000 items can be produced in < 0.03s.

代码在 GitHub 上。在那里，您还可以找到有关如何将其作为Maven / Gradle依赖项包含的说明。

The code is on GitHub. There, you'll also find instructions on how to include it as a Maven/Gradle dependency.

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