JavaServerAddin in Domino - constructor and schedule

In this article we will improve our java addin 'DemoAddin' with following features:

1. Constructor that accepts parameters when we load java addin from console.
2. We will schedule output to console amount of registered person in names.nsf (every 33 seconds).
3. Define destructor.
4. Load (with parameter) and Unload addin from console

Constructor

We will define 2 constructor, one that can accept parameters and one in case if we load addin without any parameters. It is pretty obvious how it works.

// we expect our first parameter is dedicated for secondsElapsed
public DemoAddin(String[] args) {
	this.secondsElapsed = Integer.parseInt(args[0]);
}

// constructor if no parameters
public DemoAddin() {}

Means if we run command like below it will run using constructor with parameters

load runjava org.demo.DemoAddin 33

Schedule worker

There is a method (it works but deprecated, however I have not found what should be use instead). The snippet below run constant loop, open names.nsf, read amount of users in the view People and output it to console. The main line here is this.addInRunning(), it keeps loop running forever (until we change it to this.stopAddin() or unload addin from console)

session = NotesFactory.createSession();
String server = session.getServerName();

while (this.addInRunning()) {
	/* gives control to other task in non preemptive os*/
	OSPreemptOccasionally();

	if (this.AddInHasSecondsElapsed(secondsElapsed)) {
		ab = session.getDatabase(server, "names.nsf");
		long count = ab.getView("People").getAllEntries().getCount();
		logMessage("Count of persons: " + Long.toString(count));
		ab.recycle();
	}
}

Destructor

Keep in mind that we need to be careful with Notes object, we have to release memory (recycle) after we no longer use them. So it's a good idea to create own terminate method that release memory for all Notes object you delcared and use it when addin unloads. There is also built-in method finalize so you can put code there, but I prefer to have own method and use it in places I need

private void terminate() {
	try {
		if (this.ab != null) {
			this.ab.recycle();
		}
		if (this.session != null) {
			this.session.recycle();
		}

		logMessage("UNLOADED (OK)");
	} catch (NotesException e) {
		logMessage("UNLOADED (**FAILED**)");
	}
}

Load (with parameter) and Unload addin from console

In order to run addin with parameter simply add it after name of Addin, use space as a separator when you need more than 1 parameter

load runjava org.demo.DemoAddin 33

[1098:0002-23A0] 10/20/2020 11:15:00 AM  JVM: Java Virtual Machine initialized.
[1098:0002-23A0] 10/20/2020 11:15:00 AM  RunJava: Started org/demo/DemoAddin Java task.
[1098:0004-3984] 10/20/2020 11:15:00 AM  DemoAddin: version             2
[1098:0004-3984] 10/20/2020 11:15:00 AM  DemoAddin: build date          2020-10-19 11:00 CET
[1098:0004-3984] 10/20/2020 11:15:00 AM  DemoAddin: java                1.8
[1098:0004-3984] 10/20/2020 11:15:00 AM  DemoAddin: seconds elapsed     33
[1098:0004-3984] 10/20/2020 11:15:33 AM  DemoAddin: Count of persons: 11
[1098:0004-3984] 10/20/2020 11:16:06 AM  DemoAddin: Count of persons: 11
[1098:0004-3984] 10/20/2020 11:16:39 AM  DemoAddin: Count of persons: 11
[1098:0004-3984] 10/20/2020 11:17:12 AM  DemoAddin: Count of persons: 11

When you want to unload addin using console here is a command

tell runjava unload org.demo.DemoAddin

And you should be see confirmation on console if everything went fine

[1098:0004-3984] 10/20/2020 11:26:55 AM  DemoAddin: UNLOADED (OK)
[1098:0002-23A0] 10/20/2020 11:26:55 AM  RunJava: Finalized org/demo/DemoAddin Java task.
[1098:0002-23A0] 10/20/2020 11:26:56 AM  RunJava shutdown.

If you are interested in this topic I can recommend at least two more sources NSFTools.com JavaAddinTest and AndyBrunner / Domino-JAddin or wait for new articles in my blog :-). Also feel free to ask questions if you are uncertain.

Full version of DemoAddin class is hosted on github: DominoDemoAddin

All articles in series

1. JavaServerAddin in Domino - introduction
2. JavaServerAddin in Domino - constructor and schedule