sakno / asyncj

Flexible and simple library for asynchronous non-blocking programming using Future pattern or callbacks (NodeJS-style). No third-party dependencies, no heavyweight wrappers and classes, no bullshit, just add maven dependency and build scalable applications.

AsyncJ Framework

Flexible and super lightweight library for asynchronous non-blocking programming using Future pattern, callbacks (NodeJS-style) and active objects.

Motivation

The first aim of this library is to provide lightweight implementation of Promise pattern for Java 8. Also, the library provides support for Java Future pipelining.

The second aim is to demonstrate Java 8 features, such as Lambda Expression, Method Reference

Features

AsyncJ is very lightweight thing. The implementation consists of 20 classes (approximately) from which 4 classes intended for use from user code. Despite the simple implementation, AsyncJ API is very powerful and provides the following features:

• Promise pipelining
• OSGi compatible
• Active Object support
• Core asynchronous algorithms: reduce, map-reduce, while-do

For more information about functionality and performance see project Wiki.

Examples

Promise pipelining:

final AsyncResult<Integer> ar = AsyncUtils.getGlobalScheduler().submit(() -> 42);
final Integer result = ar.then(i -> i * 2).then(i -> i + 10).get(); 

Compatibility with Java Future:

final Future<Integer> f = AsyncUtils.getGlobalScheduler().submit(() -> 42).then(i -> i + 1); 

Asynchronous try-catch:

p.then((Integer i) -> Integer.toString(i + 1), (Exception err) -> err.toString());

Callbacks:

public void sum(final AsyncCallback<Integer> callback){
    p.onCompleted((i, err1)->{
      c.onCompleted((g, err2)->{
        if(err2 != null) callback.invoke(null, err2);
        else callback.invoke(i + g, null);
      });
    });
}

Requirements

This library requires Java 8 SE or later.

Alternatives

AsyncJ doesn't provide implementation of actors, agents or messaging subsystem and require Java 8 or later. If AsyncJ doesn't fit your requirements you can choose the following alternatives:

• async4j - asynchronous programming library that provides a set of callback based constructs
• promise4j - completely type-safe implementation of Promises for Java
• Akka - building scalable applications using actors and agents
• JavaAsync as a part of Play! Framework