clrung/game-of-life-modern-java

Game Of Life implemented in Java with modern tools and language constructs

Pure Java Game Of Life

This is an implementation of Conway's Game Of Life, a zero-player game featuring an infinite plane of square cells which evolve their state as alive or dead according to a finite set of rules:

• Any live cell with fewer than two live neighbours dies, as if caused by under-population.
• Any live cell with two or three live neighbours lives on to the next generation.
• Any live cell with more than three live neighbours dies, as if by over-population.
• Any dead cell with exactly three live neighbours becomes a live cell, as if by reproduction.

(Game Of Life on Wikipedia)

The Game Of Life is a common kata to exercise in a code retreat, or to get your feet wet with a different technology. Keep the problem the same and change the conditions around it to cover new ground.

Technologies used

This project tries to take a modern approach to Java software development, producing a self-contained application which embeds everything needed to run on any JVM in a development, CI or production environment.

• Java 8 with lambdas support
• Gradle for build automation and dependency resolution (substitutes both Ant and Maven)
• Jetty as an embedded server to respond to HTTP requests
• Jersey for building the RESTful web service calculating new generations of a plane, using JAX-RS
• Freemarker templating engine to build HTML
• Log4j 2 for logging, encapsulated behind the interface slf4j.

On the testing side of things:

• JUnit 4 for unit testing infrastructure
• Mockito for Test Doubles
• JUnit Quickcheck for property-based testing
• Selenium for browser-based testing

How to run

Clone the project, then run:

./gradlew

The Gradle Wrapper will install itself.

Run

./gradlew test

to run unit, property-based and Selenium tests.

Then run

./gradlew installDist
cd build/install/game-of-life
bin/game-of-life

to install an instance in the build/ subfolder. Load http://localhost:8080/planes/a-block-and-bar in your browser to see the evolution of a test plane. The patterns featured in the sample are a stable block and a rotating bar, along with a lone cell vanishing after the first generation.

The plane shown is a configurable window of 10x10 cells having the plane origin as the top corner, but the underlying engine is capable of extending the plane dimensions automatically to use all available memory.