async-and-functional-interface

MiA Async and @FunctionalInterface

This sample shows you how to use @FunctionalInterface to execute callbacks asynchronously in MiA.

MiA offers @FunctionalInterfaces for Void (Runnable) and NonVoid (Callable) methods up to 4 arguments.
These interfaces support throwing exceptions and are exploited through the methods of the various execution stages (Task, Terminal, TerminalState) and the Async class.

Why @FunctionalInterface ? To avoid using lambdas which are not always easy to read. For Example:

public class LambdaVsFunctionalInterface {

	void synchronousMethod(String arg1, int arg2, Long arg3) {
		// ...
	}
	
	Void handleResult(Void a1, Throwable t) {
		// Handle success or failure
		return null;
	}

	public static void main(String[] args) {
		ExecutorService ex = Executors.newFixedThreadPool(1);
		try{
			LambdaVsFunctionalInterface obj = new LambdaVsFunctionalInterface();
					
			// lambda
			CompletableFuture<Void> f1 = Async.runLater(ex, ()-> obj.synchronousMethod("Hello world", 1,  12568L));
			f1.handle((r, t)-> obj.handleResult(r, t));
			
			// @FunctionalInterface
			CompletableFuture<Void> f2 = Async.runLater(ex, obj::synchronousMethod, "Hello world", 2, 12568L);
			f2.handle(obj::handleResult);
			
		} finally {
			ex.shutdownNow();
		}
	}

}

The @FunctionalInterfaces of MiA provided for creating callbacks are subclasses of Async.

Async also provides all the methods you need to use these interfaces with an asynchronous Executor (methods also implemented by Task, Terminal and TerminalState). The methods are named using the follwing principles:

• starts with run for void returning methods and call for non void methods.
• ends with Before when the execution is time constrained and Later otherwise.

See AsyncSample.java

Run this Sample with maven

mvn compile exec:java