Process Watch Dog

Java library for watching (and killing) processes.

Watch Dog thread runs only when there are same active processes to watch.

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Prerequisites

• Java 6

Usage

Copy the Maven dependency into your Maven project:

<dependency>
    <groupId>cz.net21.ttulka.exec</groupId>
    <artifactId>process-watch-dog</artifactId>
    <version>1.1.0</version>
</dependency>

Watch a Process

Create a Watch Dog object:

ProcessWatchDog watchDog = new ProcessWatchDog();

Create a process and watch it by the Watch Dog:

ProcessBuilder pb = new ProcessBuilder("myCommand", "myArg1", "myArg2");
Process p = pb.start();

watchDog.watch(p, 1000); // kill the process after 1 sec

Watch another process by the same Watch Dog:

pb = new ProcessBuilder("otherCommand");
Process p2 = pb.start();

watchDog.watch(p2, 2000); // kill the second process after 2 secs

Unwatch a Process

Unwatch a process if you don't care any longer:

watchDog.unwatch(p);

Keep a Process Alive

Normally, a process should be killed only after a timeout of inactivity. To tell the Watch Dog that the process is still active a heartbeat must be sent.

Send a heartbeat explicitly to reset the timeout:

watchDog.heartBeat(p);

Send a heartbeat automatically with every read byte:

p = watchDog.watch(p, 1000);    // reassign the `WatchedProcess` object to the process reference

InputStream is = p.getInputStream();
int b;
while ((b = is.read()) != -1) {
    // heartbeat is sent implicitly with every successful call of `read()` 
}

Alternatively, send a heartbeat explicitly via WatchedProcess object:

WatchedProcess wp = watchDog.watch(p, 1000);    // use the returned watched process object
wp.heartBeat();

Release Changes

1.1.0

Watched process with a heartbeat.

• WatchedProcess class added.
• heartBeat(Process) method added to the ProcessWatchDog class.

1.0.0

Initial version.

License

Apache License, Version 2.0