Flow Design for Java

This implementation follows the idea of the following blog entries.

• Flow-Design Cheat Sheet – Part I, Notation
• Flow-Design Cheat Sheet – Part II, Translation

With an implementation of code kata Bowling from this blog entry:

• Flowing Bowling Game Kata I

The following classes in folder src/test/java shows how to implement the flow API from blog with Java 8:

• MethodsCheatSheet shows how to transfer functional units into simple methods.
• DelegatesCheatSheet shows how to transfer functional units into methods with delegation to return values.
• EventsCheatSheet shows how to transfer functional units into classes with events.
• BowlingGame shows how to implement the bowling kata with flow design.

Also there is a class Program shows how to implement a complete program.

For productive use there are following classes in the framework:

• FunctionalUnit is a base class or template for a functional unit with one input pin and one output pin.
• Use class OutputPin as public final member or private member with getter for output pins of a functional pins.
• Use functional interface InputPut as public method for input pins of a functional pins.
• Use class Flow as template to design a flow application. This class initialize and start the flow of the application

Creating Functional Units

public abstract class MyFunctionalUnit<I, O> {

    public final OutputPin<O> result = new OutputPin<>();

    public void process(I input) {
        // process input and publish output
        O output = ...
        result.publish(output);
    }

}

Creating Wires

With one value:

MyFunctionalUnit<String, Integer> fu1 = new MyFunctionalUnit<>();
MyFunctionalUnit<Integer, String> fu2 = new MyFunctionalUnit<>();
fu1.result.connect(fu2::process());
fu1.result.publish("Foo");

Without value:

MyFunctionalUnit<String, Void> fu1 = new MyFunctionalUnit<>();
MyFunctionalUnit<Void, String> fu2 = new MyFunctionalUnit<>();
fu1.result.connect(fu2::process());
fu1.result.publish(null);