Skip to content
Android Hnefatafl game using Google Play Games Services.
Branch: master
Clone or download
Latest commit 462bccf Jun 17, 2016
Type Name Latest commit message Commit time
Failed to load latest commit information.
app Brandubh rules. Jun 17, 2016
gradle/wrapper Upgraded gradle version. Apr 17, 2016
.gitignore Update Aug 21, 2015
gradlew Initial code commit. Jul 23, 2015
gradlew.bat Initial code commit. Jul 23, 2015



Hnefatafl is a family of 2-player Viking board games, where one player tries to guide a King to a refugee square, while attackers try to prevent this. Right now, we're implementing the popular 11x11 variant - Feltar Hnefatafl. To learn more about Hnefatafl + it's history, check out this video -

Programming Patterns


Right now, we're using Retrolambda, which lets you use Java 8 lambda syntax. Essentially, this works in any situation in which you would create an anonymous class from an single-function interface. Careful though, as anything you capture will be kept around by the GC, since it is tied to the life of the lambda.

builder.setTitle("You Have Won The Game.")
  .setPositiveButton("Return to Menu", (DialogInterface sideDialog, int which) -> {

Stream API Backport

We're also using a backport of the Java 8 Stream API, which lets you do stuff like map, filter, all, etc. Perfect for use with Retrolambda.

return Stream.of(Direction.values()).allMatch((Direction dir) -> {
  // The King is only captured when surrounded on all four sides.
  Position adjacent = defendingPos.getNeighbor(dir);
  return pieces.containsKey(adjacent) && pieces.get(adjacent).hostileTo(piece);

Prefer Optional over a Nullable Variable

If you do need to have an extra "undetermined" state for a value, it might be better to use the Optional wrapper (part of the Stream backports). Optional will force you to do an isPresent check, thus preventing easy mistakes where you try to operate on a null object.


  • Generally avoid nulls
  • Try to use final wherever it makes sense.
  • Prefer creating a getter over simply making a variable public (yeah I know, it's verbose, but it communicates that outside classes shouldn't just change the value)
  • Prefer composition over inheritance (Gang of Four / Effective Java advice)


  • Simulator - The simulator handles all of the rules of Hnefatafl, exporting the Boardclass that represents the state of a game.
  • Hnefatafl AI - This package implements various strategies for controlling the AI player in Player vs. AI games.
  • The Game - This package handles all of the drawing / input, using LibGDX.

Assets Used

You can’t perform that action at this time.