/**
* Detecting factory, based on the position of the rails. The base must be one block below and the
* sign if it exists must be two or three blocks below. Signs are guaranteed to be signs (unless
* they're null) and rails are guaranteed to be rails.
*
* <p>This is the most important constructor, since it is the one invoked when processing cart
* move events.
*
* @param rail the block containing the rails.
*/
public static CartMechanismBlocks findByRail(Block rail) throws InvalidMechanismException {
if (!BlockType.isRailBlock(rail.getTypeId()))
throw new InvalidMechanismException("rail argument must be a rail!");
if (SignUtil.isSign(rail.getFace(BlockFace.DOWN, 2).getTypeId())) {
return new CartMechanismBlocks(
rail, rail.getFace(BlockFace.DOWN, 1), rail.getFace(BlockFace.DOWN, 2));
} else if (SignUtil.isSign(rail.getFace(BlockFace.DOWN, 3).getTypeId())) {
return new CartMechanismBlocks(
rail, rail.getFace(BlockFace.DOWN, 1), rail.getFace(BlockFace.DOWN, 3));
}
return new CartMechanismBlocks(rail, rail.getFace(BlockFace.DOWN, 1), null);
}
/**
* Detecting factory; defers to one of the other three specific detecting factories based on
* whether the given unknown block appears to be a sign, rail, or base.
*
* @param unknown the block to examine.
*/
public static CartMechanismBlocks find(Block unknown) throws InvalidMechanismException {
final int ti = unknown.getTypeId();
if (SignUtil.isSign(ti)) return findBySign(unknown);
else if (BlockType.isRailBlock(ti)) return findByRail(unknown);
else return findByBase(unknown);
}