Yield Return In Java

Question

I\'ve created a linked list in java using generics, and now I want to be able to iterate over all the elements in the list. In C# I would use yield return insid

Answer 1

It's been ages since this question was posted, and I'm quite unsure about writing an answer to such an old question, but another way of achieving this has occurred to me and I want to present it here in case it helps anyone searching for this, given the fact that this SO thread was one of the very first hits in Google.

The code shown below has been compiled in my head. There's absolutely no guarantee it's correct, but the idea behind it is.

Use callbacks

Yes, I know, it is not the same as a yield return. But I don't think OP wanted specifically a replacement that could be (with the appropriate amount of sugar) dropped into a for (var x : ). My approach instead does something more akin to C#'s linq (or Java's stream()), not the yielded return.

@FunctionalInterface
public interface Looper {
    void each(T item);
}



public interface Loopable {
    void forEach(Looper looper);
}

Then you would implement Loopable in your code, creating this pseudo-iterator. Which is really not, it's just making use of @FunctionalInterfaces, which is Java's way of doing callbacks (sorta)

public class WhatEvs implements Loopable {
    // ...
    @Override
    public void forEach(Looper looper) {
        while(your_condition) {
            WhatEvs nextItem = getNextItem();
            looper.each(nextItem);
        }
    }
}