New in Kermeta 2

It is possible to declare a class as a singleton. The singleton works like companion object in scala or is similar to a static class in java. Which means that only a single instance of the class exists in memory.

Access to this instance is done directly via the class name.

As any class, the singleton supports operations, attributes, references...

singleton StdIO
{
	/**
	 * Writeln the object to standard output
	 */ 
	operation writeln(object : String) : Void is do
		// code for printing on console
	end
	// other operations in StdIO
}

kermeta::io::StdIO.writeln("my message")

	Caution
	Be careful when deploying a code that use singleton in environment that uses multiple classpath. For example in OSGI and eclipse, you can (on purpose or not) create several classpathes that aren't shared and create several instances of the same singleton.