The easiest way to publish & consume events to/from SAP Event Mesh using java applications

[maxi1555]

Hi experts,

I want to share the easiest way to publish & consume events to/from SAP Event Mesh using java applications, so let's publish 1 million of events in a topic and later on consume them from a queue 🙂

The only pre-requisite is to use the libraries explained here

1-Publish events in a topic:

	public static void publish(String client_id, String client_secret, String token_url, String service_url,

			String topic_name) throws Exception {



		MessagingService messagingService = new MessagingService();

		messagingService.setClientId(client_id);

		messagingService.setClientSecret(client_secret);

		messagingService.setOAuthTokenEndpoint(token_url);

		messagingService.setProtocol("amqp10ws");

		messagingService.setServiceUrl(service_url);



		MessagingServiceJmsSettings settings = new MessagingServiceJmsSettings();



		MessagingServiceFactory messagingServiceFactory = MessagingServiceFactoryCreator

				.createFactory(messagingService);

		MessagingServiceJmsConnectionFactory connectionFactory = messagingServiceFactory

				.createConnectionFactory(MessagingServiceJmsConnectionFactory.class, settings);



		Connection connection = connectionFactory.createConnection();

		Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);



		connection.start();



		Destination destination = session.createTopic("topic:" + topic_name);

		MessageProducer producer = session.createProducer(destination);



		for (double i = 0; i < 1000000; i++) {



			String text = "test " + i;

			TextMessage message = session.createTextMessage(text);

			producer.send(message);



		}

	}

2-Consume them from a queue:

	public static void consume(String client_id, String client_secret, String token_url, String service_url,String queue_name) throws Exception {

		

		MessagingService messagingService = new MessagingService();

		messagingService.setClientId(client_id);

		messagingService.setClientSecret(client_secret);

		messagingService.setOAuthTokenEndpoint(token_url);

		messagingService.setProtocol("amqp10ws");

		messagingService.setServiceUrl(service_url);



		MessagingServiceJmsSettings settings = new MessagingServiceJmsSettings();



		MessagingServiceFactory messagingServiceFactory = MessagingServiceFactoryCreator.createFactory(messagingService);

		MessagingServiceJmsConnectionFactory connectionFactory = messagingServiceFactory.createConnectionFactory(MessagingServiceJmsConnectionFactory.class, settings);



		Connection connection = connectionFactory.createConnection();

		Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);



		connection.start();

		Queue queue = session.createQueue("queue:" + queue_name);



		MessageConsumer consumer = session.createConsumer(queue);

		consumer.setMessageListener(new MessageListener() {



			@Override

			public void onMessage(Message message) {

				// TODO Auto-generated method stub

				try {

					String messageText = null;



					if (message instanceof TextMessage) {

						messageText = ((TextMessage) message).getText();

					} else if (message instanceof BytesMessage) {

						BytesMessage bytesMessage = (BytesMessage) message;

						byte[] data = new byte[(int) bytesMessage.getBodyLength()];

						bytesMessage.readBytes(data);

						messageText = new String(data);

					}



					System.out.println("Message received:" + messageText);

				} catch (JMSException e) {

					e.printStackTrace();

				}

			}

		});

		do {



		} while (true);

	}

3-Test it

Execute your java application and you will see that after 7 minutes all the events were consumed:

Queue cleaned:

 

I can see events everywhere in our future with SAP Business Technology Platform, and how about you, will you use them?, share your experience 🙂

 

Max.