I have the following problem: I run an iterative algorithm written in Java on a workstation. The workstation uses SGE under the hood. For each job you have to set a soft and hard time limit. When the soft time limit is reached, the running program receives a SIGUSR1. When the hard time limit is reached, it is a SIGKILL instead.
I would like to be able to handle the SIGUSR1 by stopping at the current iteration and writing the current solution to a file. The canonical way to do this in a C application would be to trap the signal in a signal handler, set a boolean flag which is checked periodically during the iteration and triggers the termination.
The java program looks like this:
public class TestInterrupt
{
public static volatile boolean shouldTerminate = false;
public static void main(final String[] args) throws InterruptedException
{
int i = 0;
while (++i < 100)
{
Thread.sleep(1000);
if(shouldTerminate) {
break;
}
}
// write data to file here.
}
}
There are no signal handlers in java (afaik). I wrapped the java application in a bash script which can trap the signal. Question is, how can I notify the java application? Is there some standard mechanism for this?
I have seen this similar thread which revolves around using shutdown handlers. The answer was accepted. However, as far as I saw (and as far as the API docs tell), shutdown hooks are run as threads only after shutdown has been initiated rather then immediately when a SIGINT or similar is received, so I don't see how they would be useful to trap a signal.
