This is a demo project that I implemented during one of the recruitment processes in February 2016. The goal was to create a currency converter application which integrates with an external API.
My implementation may seem overengineered in some places but it was a conscious decision to build this in such a way that it would be a good starting point for a real project.
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Spring Framework - must-have on every project :-)
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Spring Boot - a brilliant collection of best practices and reusable components like Maven "starter" dependencies, Spring autoconfiguration, embedded containers, externalized properties, Spring Actuator (monitoring and management). All this could of course be configured manually and I have done most of it in the past (yes, even in the dark ages of XML configuration - without annotations or Spring JavaConfig! ;-) but I am a strong believer in the DRY (Don't Repeat Yourself) principle.
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Spring Data - Spring Data is a huge help when implementing your data access layer.
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JPA - with Hibernate as persistence provider and hsqldb (in-memory) as database.
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Ehcache - for caching external calls, nicely integrates with Spring thanks to Spring Boot's autoconfiguration features (when ehcache is detected on classpath, configured cache manager is automatically created for you). ehcache.xml contains settings for cache sizing, TTL, persistence...
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Thymeleaf - pretty cool view technology which nicely integrates with Spring MVC. This was actually my first time using it and I chose it because I just couldn't bring myself to using JSP in 2016 ;-)
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Cucumber - for BDD-style tests - take a look at scenarios here.
To build the code you need JDK 8 and Maven >= 3.2.
- Clone repo.
mvn clean package
This builds a Spring Boot executable jar file with embedded Tomcat.
cd targetjava -jar currency-converter-0.0.1-SNAPSHOT.jar
This should start the embedded Tomcat and the application will be available at http://localhost:8080/.
application.properties contains various settings including OpenExchangeRates.org app id which is required for calling the API. These properties can be adjusted according to the standard Spring Boot way of externalizing configuration.
After you register and log in you will be able to access Spring Actuator endpoints, e.g. http://localhost:8080/dump for thread dump, health indicators and much more. Full list of endpoints can be found here.
Spring Actuator also exposes JMX MBeans so it's possible to connect to the JVM with jvisualvm.
Build and deployment jobs are on Jenkins here:
http://jenkins.jcore.pl/ (currency-converter-* jobs should be accessible without authentication)
- Add more user input validation errors ("reasonable" birth date)