Create a custom event in Java

Question

I want to do something like this in Java but I don't know the way:

When event "object 1 say 'hello'" happens, then object 2 responds to that event by saying "hello".

Can somebody give me a hint or sample code?

Answer 1

To Create a custom event in Java.

import java.util.*;

 

interface HelloFun {

    void SaidHello();

}

 

// Someone who says "Hello"

class Initiater{

    private List<HelloFun> listeners = new ArrayList<HelloFun>();

 

    public void addListener(HelloFun toAdd) {

        listeners.add(toAdd);

    }

 

    public void sayHello() {

        System.out.println("Hello!!");

 

        // Notify everybody that may be interested.

        for (HelloFun hl : listeners)

            hl.SaidHello();

    }

}

class Responder implements HelloFun {

    public void SaidHello() {

        System.out.println("Hello there...");

    }

}

 

class Test {

    public static void main(String[] args) {

        Initiater initiater = new Initiater();

        Responder responder = new Responder();

 

        initiater.addListener(responder);

 

        initiater.sayHello();      }

}