为什么我的DelayQueue不会以错误的顺序延迟和打印？(Why is my DelayQueue not delaying and printing in the wrong order?)

 我有以下假设的一个简单的DelayQueue演示。 
 
class DelayedThing implements Delayed {

    private final long waitUntil;
    private final String name;

    public DelayedThing(String name, long wait) {
        this.name = name;
        this.waitUntil = System.currentTimeMillis() + wait;
        System.out.println("DelayedThing(" + name + " wait=" + wait + " until-" + waitUntil);
    }

    @Override
    public long getDelay(TimeUnit unit) {
        System.out.println(name + " getDelay = " + unit.convert(waitUntil - System.currentTimeMillis(), TimeUnit.MILLISECONDS));
        return unit.convert(waitUntil - System.currentTimeMillis(), TimeUnit.MILLISECONDS);
    }

    @Override
    public int compareTo(Delayed o) {
        long diff = this.getDelay(TimeUnit.MILLISECONDS) - o.getDelay(TimeUnit.MILLISECONDS);
        System.out.println(name + ".compareTo(" + o + ") = " + diff);
        return Long.signum(diff);
    }

    @Override
    public String toString() {
        return name;
    }
}

public void test() throws InterruptedException {
    BlockingQueue<Delayed> queue = new DelayQueue<>();
    queue.add(new DelayedThing("one second", 1000));
    queue.add(new DelayedThing("two seconds", 2000));
    queue.add(new DelayedThing("half second", 500));
    for (Delayed d : queue) {
        System.out.println(d);
    }
}
 
 但它打印出来 
 
half second
two seconds
one second
 
 这显然是错的。 

I have the following supposedly trivially simple demo of a DelayQueue.
 
class DelayedThing implements Delayed {

    private final long waitUntil;
    private final String name;

    public DelayedThing(String name, long wait) {
        this.name = name;
        this.waitUntil = System.currentTimeMillis() + wait;
        System.out.println("DelayedThing(" + name + " wait=" + wait + " until-" + waitUntil);
    }

    @Override
    public long getDelay(TimeUnit unit) {
        System.out.println(name + " getDelay = " + unit.convert(waitUntil - System.currentTimeMillis(), TimeUnit.MILLISECONDS));
        return unit.convert(waitUntil - System.currentTimeMillis(), TimeUnit.MILLISECONDS);
    }

    @Override
    public int compareTo(Delayed o) {
        long diff = this.getDelay(TimeUnit.MILLISECONDS) - o.getDelay(TimeUnit.MILLISECONDS);
        System.out.println(name + ".compareTo(" + o + ") = " + diff);
        return Long.signum(diff);
    }

    @Override
    public String toString() {
        return name;
    }
}

public void test() throws InterruptedException {
    BlockingQueue<Delayed> queue = new DelayQueue<>();
    queue.add(new DelayedThing("one second", 1000));
    queue.add(new DelayedThing("two seconds", 2000));
    queue.add(new DelayedThing("half second", 500));
    for (Delayed d : queue) {
        System.out.println(d);
    }
}
 
but it prints
 
half second
two seconds
one second
 
which is obviously wrong.

原文：https://stackoverflow.com/questions/32206562