UsamaAshraf

module.exports = (user) => {
  // Send a welcome email or whatever.
}

UsamaAshraf

const myEmitter = require('./my_emitter');
const sendEmailOnRegistration = require('./send_email_on_registration');
const someOtherListener = require('./some_other_listener');


myEmitter.on('user-registered', sendEmailOnRegistration);
myEmitter.on('user-registered', someOtherListener);

UsamaAshraf

const myEmitter = require('./my_emitter');

myEmitter.on('user-registered', (user) => {
  // Send an email or whatever.
});

UsamaAshraf

const myEmitter = require('./my_emitter');

// Perform the registration steps

// Pass the new user object as the message passed through by this event.
myEmitter.emit('user-registered', user);

UsamaAshraf

const EventEmitter = require('events');

const myEmitter = new EventEmitter();

module.exports = myEmitter;

UsamaAshraf

public static void main(String[] args) throws Exception
{
    TopologyBuilder builder = new TopologyBuilder();

    builder.setSpout("word", new TestWordSpout(), 10);

    builder.setBolt("exclaim1", new ExclamationBolt(), 3).shuffleGrouping("word");

    builder.setBolt("exclaim2", new ExclamationBolt(), 2).shuffleGrouping("exclaim1");

UsamaAshraf

# Telling the Supervisor where the Zookeeper is.
storm.zookeeper.servers:
  - "zookeeper"

# The worker nodes need to know which machine(s) are the candidate of master
# in order to download the topology jars.
nimbus.seeds : ["storm-nimbus"]

# For each Supervisor, we configure how many workers run on that machine. 
# Each worker uses a single port for receiving messages, and this setting 

UsamaAshraf

# The Nimbus needs to know where the Zookeeper is. This specifies the list of the
# hosts in the Zookeeper cluster. We're using just one node, of course.
# 'zookeeper' is the Docker Compose network reference.
storm.zookeeper.servers:
  - "zookeeper"

UsamaAshraf

version: '3.2'

services:
    zookeeper:
        build: ./zookeeper
        # Keep it running.  
        tty: true

    storm-nimbus:
        build: ./storm-nimbus

UsamaAshraf

package packagename

// …
  
public class OurSimpleTopology { 
 
  public static void main(String[] args) throws Exception
  {
    // Create the topology
    TopologyBuilder builder = new TopologyBuilder();