Get notification when external application is fully running - Java

Question

I am writing a program in java which can start up applications such as, for example, firefox.

Edit: This program is for linux, specifically ubuntu.

It's easy to start the program:

Runtime.getRuntime().exec("/usr/bin/firefox");

However, I want to retrieve details from the window once it is fully opened or running.

At the moment I'm just calling:

Thread.sleep(delay);

To make sure the window is ready, but this is a poor solution. Different windows requiring different delays is a problem.

Messy.

So my question is, is there any way that I can be notified when firefox (or any other external application for that matter) is fully setup? I don't think I could use Process.waitFor() because the Process won't be finished until firefox is closed.

Thanks in advance!

Update: Process.waitFor() doesn't work. I have tried it and it only returns when firefox is closed, not when it is fully setup. Just for anyone trying it themselves, if another firefox window is already open it will work (which fooled me at first) but if there is no existing window it won't!

Answer 1

Ok I have been doing some more thinking and I have a reasonably satisfactory answer.

Instead of waiting until the window is ready, continually search for it with xdotool:

while(line == null){
        writer.write("xdotool search --onlyvisible --name " + name + "\n");
        writer.flush();
        if(reader.ready())
            line = reader.readLine();

        Thread.sleep(1000);
}

xdotool will only print a string if it finds a window called name.

So if the reader is ready() then you know the window is open.

The Thread.sleep() is necessary because if it is not present xdotool will spit out a bad window error and the reader will read that.

However, it seems to almost be faster to use a standard delay like I spoke about above but this solution will work even for windows which take longer to load, rather than trying to guess a delay.

Answer 2

You can use Process#waitFor to wait till the command gets executed and then check the exitValue like this:

Process p = Runtime.getRuntime().exec("/usr/bin/firefox");
p.waitFor();

if(p.exitValue()==0) {

  //success
} else {
  // fail read error stream or out stream for possible causes
}