Why is Robot.delay(int ms) limited to 1 minute?

Question

I got the following exception while executing my software:

Exception in thread "main" java.lang.IllegalArgumentException: Delay must be to 0 to 60,000ms
    at java.awt.Robot.checkDelayArgument(Robot.java:544)
    at java.awt.Robot.delay(Robot.java:534)
    at com.company.Main.main(Main.java:10)

It surprises me that there is a sleeping time limit and that the standard library exception message has bad grammar/a typo (to 0 to?). After checking the source code of the delay() method, I noticed that it restricts the waiting time as the exception stated:

/**
 * Sleeps for the specified time.
 * To catch any <code>InterruptedException</code>s that occur,
 * <code>Thread.sleep()</code> may be used instead.
 * @param   ms      time to sleep in milliseconds
 * @throws  IllegalArgumentException if <code>ms</code> is not between 0 and 60,000 milliseconds inclusive
 * @see     java.lang.Thread#sleep
 */
public synchronized void delay(int ms) {
    checkDelayArgument(ms);
    try {
        Thread.sleep(ms);
    } catch(InterruptedException ite) {
        ite.printStackTrace();
    }
}

private static final int MAX_DELAY = 60000;

private void checkDelayArgument(int ms) {
    if (ms < 0 || ms > MAX_DELAY) {
        throw new IllegalArgumentException("Delay must be to 0 to 60,000ms");
    }
}

Why is this being done? It seems like poor API design. Which purpose does it have besides catching the redundant InterruptedException checked exception for you and synchronizes the call?

It seems rather useless. Somebody designed it that way on purpose, but I see no benefit. I also cannot find an explanation for it in the documentation. — f1sh, Sep 19 '19 at 12:35
I originally commented that I thought the grammar was correct because my brain totally filled in the missing "set" in the sentence. Perhaps the original author had the same issue ;) — arcadeblast77, Sep 19 '19 at 12:38
"*It surprises me that there is a sleeping time limit and that the standard library exception message has bad grammar/a typo*" much to learn, you still have — Michael, Sep 19 '19 at 12:51

score 2 · Accepted Answer · answered Sep 19 '19 at 12:44

No one can answer that apart from the original developer(s).

You can quite clearly see that all it does is call Thread::sleep, so just do the same thing. You don't need to call Robot::delay.

The following is precisely equivalent, without the arbitrary restriction

Robot r;
long sleepDuration = 60001;
synchronized (r) {
    try {
        Thread.sleep(sleepDuration);
    } catch(InterruptedException ite) {
        ite.printStackTrace();
    }
}

It seems like poor API design

This class is 19 years old. There's plenty of bad design decisions in the JDK, especially in the older stuff.

Why is Robot.delay(int ms) limited to 1 minute?

1 Answers1