Currency Converter - Demo Exercise Project

A project I wrote to demonstrate several facets. Other than pure curiosity or examination, there is little real-world value of the built-in features.

• Java EE 7 compliant application.
• Writen using Java 8 features.
• Consumes data from Open Exchange Rates via their REST API.
• Exposes currency conversion endpoints in a REST API.
• Uses PostgreSQL as database.
• Autogenerates API spec. and documentation at build time via Swagger Maven Plugin.
• Bundles with Swagger UI for examining and testing the implemented API.

Stuff/APIs Worth a List

• Lombok is used extensively.
• Java EE 7: CDI, JPA (via Hibernate), EJB, JAX-RS (server and client specs.), Bean Validation.
• QueryDSL as a substitute to plain JPQL and the JPA Criteria API.
• Swagger for API spec.
• RestAssured for Integration Tests.

Prerequisites

• Linux or MacOS machine. The development was done on MacOS El Capitan.

• JDK 8. For development the MacOS 64 bits distribution from Oracle was used.

• Apache Maven 3.3.*. Installable via homebrew/macports on Mac OS and linux package managers.

• Download the WildFly 10.0.0 distribution zip from: http://download.jboss.org/wildfly/10.0.0.Final/wildfly-10.0.0.Final.zip and extract it somewhere in your machine where the current user has write access.

• A PostgreSQL server version 9.3 or higher running on the machine and access as a user with privileges to create databases. Installable via homebrew/macports on Mac OS and linux package managers. Setting up authentication for accessing the PostgreSQL database is done via the pg_hba.conf file. A tradeoff solution could be to temporarily allow usecure access by means of a line in the form:

    host    all             all             127.0.0.1/32            md5
  

Instructions

The following will be assumed from now on:

• This repo has been cloned into a directory named currency-converter.
• <WildFlyDir> will be the directory where the wildfly-10.0.0.Final.zip file has been extracted. In my machine, this for example is ~/opt/wildfly-10.0.0.Final.

To setup the database

   $ cd currency-converter/deploy/db

Edit the pg-db.conf file and set the PG_USER to the name of the administrative user for postgres. It will be used to create the database. For Debian-based distros this typically is postgres. Also, if a value different than localhost is to be used to connect to the database, the DB_HOST variable must be set. This also applies to the above Debian-based distros (and probably others): a value of /var/run/postgresql is valid.

Also, edit the same file and set PG_PATH variable to the base path where the PostgreSQL command-line utilities lie in your system. There are some commented samples for some linux distributions.

     $ ./00_setup-db.sh

When prompted for the password for the currencyconverter user, please use currencyconverter as well to simplyfy the deployment. The password will need to be entered twice.

You should see something like, meaning everything went fine.

    miguelgl@MacBook-Pro:SQL$ ./00_setup-db.sh
    ---> Creating DB user 'currencyconverter' ...
    Enter password for new role:
    Enter it again:
    ---> Done
    ---> Creating DB 'currencyconverter' owned by 'currencyconverter' ...
    ---> Done
    ---> Creating DB 'currencyconverter' tables ...
     setval
    --------
          1
    (1 row)
    
     setval
    --------
          1
    (1 row)
    
    ---> Done

Start the Application Server

  $ cd <WildFly>/bin
  $ ./standalone.sh

Please leave this terminal running the program and outputing the server logs and open a new terminal.

To setup the Application Server:

   $ cd currency-converter/deploy

Edit defaults.conf and set the WILDFLY_BASE_DIR variable to point to your in your machine. If you changed nothing else (just followed these instructions), leave all other parameters unchanged.

   $ ./provision-wildfly.sh

You should see an output of the like, which means everything went fine:

    miguelgl@MacBook-Pro:Deployment$ ./provision-wildfly.sh
    [[email protected]:9990 /] module add --name=org.postgres
      --resources=postgresql-9.4.1208.jre7.jar
      --dependencies=javax.api,javax.transaction.api
    [[email protected]:9990 /]
    [[email protected]:9990 /]
    /subsystem=datasources/jdbc-driver=postgres:add(
    driver-name="postgres",
    driver-module-name="org.postgres",
    driver-class-name="org.postgresql.Driver",
    driver-xa-datasource-class-name="org.postgresql.xa.PGXADataSource")
    {"outcome" => "success"}
    [[email protected]:9990 /]
    [[email protected]:9990 /] xa-data-source add
    --name=CurrencyConverterXADS
    --driver-name=postgres
    --jndi-name=java:jboss/datasources/CurrencyConverterXADS
    --user-name=currencyconverter
    --password=currencyconverter
    --use-java-context=true
    --use-ccm=true
    --min-pool-size=10
    --max-pool-size=100
    --pool-prefill=true
    --allocation-retry=1
    --prepared-statements-cache-size=32
    --share-prepared-statements=true
    --xa-datasource-properties=ServerName=localhost,PortNumber=5432,DatabaseName=currencyconverter
    --valid-connection-checker-class-name=org.jboss.jca.adapters.jdbc.extensions.postgres.PostgreSQLValidConnectionChecker
    --exception-sorter-class-name=org.jboss.jca.adapters.jdbc.extensions.postgres.PostgreSQLExceptionSorter
    [[email protected]:9990 /] xa-data-source enable --name=CurrencyConverterXADS
    operation-requires-reload: true
    process-state:             reload-required
    [[email protected]:9990 /] reload
    [[email protected]:9990 /]

To Compile the project

   $ cd currency-converter
   $ mvn clean install -DskipTests=true

This may take a very long the first time while maven downloads everything.

To Deploy the solution

   $ cd currency-converter/server/api-server
   $ mvn wildfly:deploy -DskipTests=true

You should see the previous terminal dedicated to running the application server outputing lots of logs during the deployment.

Upon success, maven will report something like:

    miguelgl@MacBook-Pro:api-server$ mvn wildfly:deploy -DskipTests=true
    ...
    INFO: JBoss Remoting version 4.0.9.Final
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 16.584 s
    [INFO] Finished at: 2016-04-22T22:23:45+02:00
    [INFO] Final Memory: 37M/358M
    [INFO] ------------------------------------------------------------------------

To Run the Unit Tests (Integration Tests, really)

   $ cd currency-converter
   $ mvn test

Upon success, maven will report something like:

    ...
    Tests run: 2, Failures: 0, Errors: 0, Skipped: 0
    ...
    Tests run: 1, Failures: 0, Errors: 0, Skipped: 0
    
    [INFO] ------------------------------------------------------------------------
    [INFO] Reactor Summary:
    [INFO]
    [INFO] CURRCONV :: --- .................................... SUCCESS [  0.435 s]
    [INFO] CURRCONV :: Providers :: --- ....................... SUCCESS [  0.005 s]
    [INFO] CURRCONV :: Providers :: API ....................... SUCCESS [  0.435 s]
    [INFO] CURRCONV :: Providers :: OXR ....................... SUCCESS [  3.854 s]
    [INFO] CURRCONV :: Server :: --- .......................... SUCCESS [  0.003 s]
    [INFO] CURRCONV :: Server :: API Server ................... SUCCESS [  6.666 s]
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time: 11.818 s
    [INFO] Finished at: 2016-04-22T22:25:55+02:00
    [INFO] Final Memory: 30M/284M
    [INFO] ------------------------------------------------------------------------

To access the served components

• API Doc: http://localhost:8080/converter/api-doc/api-doc.html
• API Tester UI: http://localhost:8080/converter/swagger-ui/index.html

Other considerations

• Running mvn wildfly:undeploy will undeploy the solution from the application server.
• The application server can be stopped with a kill -SIGINT <pid>.
• There are other scripts in the deploy/db dir to cleanup the created database and user.