問題描述

我想在 Java 中實現一個 Iterator，它的行為有點像 Python 中的以下生成器函數:

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 可以是多維數組或某種形式的嵌套集合.我不確定這將如何工作.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?

推薦答案

有同樣的需求，所以寫了一個小類.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".

無限生成器也是可能的:

Infinite generators are also possible:

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

Generator 類在內部使用線程來生成項目.通過覆蓋 finalize()，它可以確保在相應的 Generator 不再使用時不會留下任何線程.

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.

性能顯然不是很好，但也不算太差.在我的具有雙核 i5 CPU @ 2.67 GHz 的機器上，可以在 < 中生產 1000 個項目.0.03 秒.

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.

代碼位于 GitHub.在那里，您還可以找到有關如何將其作為 Maven/Gradle 依賴項包含在內的說明.

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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