лекция #2: NonBlockingStack

Реализация неблокирующего стека на java.util.concurrent.atomic.AtomicReference:

import java.util.concurrent.atomic.AtomicReference;
import java.util.EmptyStackException;

class NonBlockingStack {
    private AtomicReference head = new AtomicReference(null);
    public void push(int data) {
        for (; ;) {
            Node next = (Node) head.get();
            Node myNode = new Node(data, next);
            if (head.compareAndSet(next, myNode)) {
                return;
            }
        }
    }

   public int pop() {
        for (;;) {
            Node currHead = (Node) head.get();
            if (currHead == null) {
                throw new EmptyStackException();
            }
            if (head.compareAndSet(currHead, currHead.next)) {
                return currHead.data;
            }
        }
    }

    private static class Node {
        private final int data;
        private final Node next;
        public Node(int data, Node next) {
            this.data = data;
            this.next = next;
        }
    }
}