CODEWITHSUNDEEP
javaapi-designawtrobot
BullyWiiPlaza
BullyWiiPlaza

Reputation: 19225

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

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?

Upvotes: 6

Views: 548

Answers (1)

Michael
Michael

Reputation: 44230

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.

Upvotes: 2

Related Questions