Java列表中的移交手锁定

Question

我想解决线程问题。我已经链接了类型为myList的列表，这些列表应该对数字求和，而没有任何线程阻塞它们。但是，当我使用synchronized关键字时，线程将被阻塞。如何修改我的代码以使用“越过上锁”？

我的列表类别：

public class myList<T> {

    private final Object Lock;
    private Node<T> first;

    private class Node<K> {
        private K elem;
        private Node<K> prev;
        private Node<K> next;

        private Node(final K elem, final Node<K> prev, final Node<K> next) {
            this.elem = elem;
            this.prev = prev;
            this.next = next;
        }
    }

    public myList() {
        this.Lock = new Object();
        this.first = null;
    }

    public T get(final int i) {
        synchronized (this.Lock) {
            Node<T> node = this.first;
            for (int j = 0; j < i; j++) {
                node = node.next;
        }
    }

    public boolean add(final T e) {
        synchronized (this.Lock) {
            if (this.first != null) {
                Node<T> node= this.first;
                while (node.next != null) {
                    node= node.next;
                }
                node.next = new Node<>(e, ptr, null);
            } else {
                this.first = new Node<>(e, null, null);
            }
            return true;
        }
    }

主要方法：

public class Main {
    static myList<Integer> list;

    static Runnable sum(final int start, final int end, final int expected) {
        return () -> {
            int sum = 0;
            for (int i = start; i < end; i++) {
                sum += list.get(i);
            }
            if (sum != expected) {
                System.out.println("Error in Thread");
            }
        };
    }

    public static void main(final String[] args) throws InterruptedException {
        Thread thread0, thread1;
        list = new ThreadsafeSimplifiedList<>();
        for (int i = 0; i < 2500; i++) {
            list.add(i);
        }
        thread0 = new Thread(sliceSum(0, 1250, 780625));
        thread1 = new Thread(sliceSum(1250, 2500, 2343125));
        thread0.start();
        thread1.start();
        thread0.join();
        thread1.join();
        System.out.printf("%s, %d", list.getClass().toString(), System.currentTimeMillis());
    }
}

Answer 1

在此示例中，我根本看不到为什么需要同步，因为没有并发添加或并发添加和获取。