GarciaPL Notes - Java and Others

Some of you might have a knowledge that one of the IT company has created a technical test. For recruitment process of course. I decided to take up this challenge. Below you can find a solution of it. I posted this only for educational purposes.

The projects is splited into two modules : currencyfair-gateway and currencyfair-consumer.

The first module currencyfair-gateway is responsible for exposing endpoint used for retriving from user request in JSON format. Request is validated due to it's fields. If request is not valid user will receive detailed information about which fields are incorrect. Otherwise request will be forwarded to message broker RabbitMQ.

The second module currencyfair-consumer fetches messages from message broker RabbitMQ to process it via Data Processor. Once it's done the processed data are broadcasted to frontend.
Application was developed using of course Java and Spring Framework. Those above two modules were connected via message broker RabbitMQ. Below you can see what is the overall architecture of this application. Other used libraries :

• Spring Beans – 4.0.1.RELEASE
• Spring Tx – 4.0.1.RELEASE
• Spring Context – 4.0.1.RELEASE
• Spring Context Support – 4.0.1.RELEASE
• Spring Aop – 4.0.1.RELEASE
• Spring Aspects - 4.0.1.RELEASE
• Spring Web – 4.0.1.RELEASE
• Spring Web MVC – 4.0.1.RELEASE
• Spring AMQP - 1.4.5.RELEASE
• Spring Erlang - 1.4.5.RELEASE
• Spring Rabbit - 1.4.5.RELEASE
• Spring WebSocket - 4.0.1.RELEASE
• Spring Messaging - 4.0.1.RELEASE
• Spring Integration - 4.1.0.RELEASE
• Spring Integration AMQP - 4.1.0.RELEASE
• Spring Integration Stream - 4.1.0.RELEASE
• Spring Test - 4.0.1.RELEASE
• Jackson Core - 2.5.0
• Jackson Databind - 2.5.0
• Jackson Annotations - 2.5.0
• Jackson Mapper ASL – 1.9.10
• Gson – 2.2.4
• Guava - 18.0
• Unirest - 1.4.5
• Javax Servlet API – 3.1.0
• JSTL – 1.2
• SLF4J - 1.7.8
• Commons Logging - 1.2
• JUnit - 4.10
• Mockito - 1.9.5
• Hamcrest - 1.3
• Highcharts - 4.1.5
• Twitter Bootstrap - 3.3.4
• SockJS - 0.3.4

Architecture

Endpoint

{ 
    "userId": "12345",
    "currencyFrom": "EUR",
    "currencyTo": "GBP",
    "amountSell": 1000,
    "amountBuy": 747.10,
    "rate": 0.7471,
    "timePlaced" : "24-JAN-15 10:27:44",
    "originatingCountry" : "FR"
}

Data processor

GraphBroker

Frontend

I recently uploaded my portfolio on GitHub Pages. If you are interested in projects which was developed just visit below website :

GarciaPL.github.io

My main IDE which is used at this time to develop for example Spring application is IntelliJ IDEA 13.1. My last project is built on Spring Framework 4. There is no so much problems with it, but there is one with Spring WebSocket. When you are going to autowire SimpMessagingTemplate object there is an error :

"Could not Autowire. No beans of 'SimpMessagingTemplate' type found"

The solution is very simple. Just add in your bean xml, in my case it's dispatcher-servlet.xml this line :

<context:component-scan base-package="org.springframework.web.socket.config"/>

As far as I know this problem is fixed in Intellij IDEA 14.0. Below you can read about ticket which is strictly related with this issue.

If this solution above did not work perhaps you need to move bean definition of your class which contains Autowired field of SimpMessagingTemplate to dispatcher-servlet.xml, I mean context which is pointed in your web.xml by org.springframework.web.servlet.DispatcherServlet.


Reference :
[1] Jetbrains IDEA-123964