@Override
public Cells nextGen(Cells cells) {
final int row = cells.getRow();
final int col = cells.getCol();
for (int r = 0; r < row; r++) {
for (int c = 0; c < col; c++) {
Cell cell = cells.getCell(r, c);
// Determine alive neighbour size.
int aliveNeighbourSize = 0;
// TOP ROW
int _r = r - 1;
_r = _r >= 0 ? _r : row - 1;
int _c = c - 1;
_c = _c >= 0 ? _c : col - 1;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
_c = c;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
_c = c + 1;
_c = _c < col ? _c : 0;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
// SAME ROW
_r = r;
_c = c - 1;
_c = _c >= 0 ? _c : col - 1;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
_c = c + 1;
_c = _c < col ? _c : 0;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
// BOTTOM ROW
_r = r + 1;
_r = _r < row ? _r : 0;
_c = c - 1;
_c = _c >= 0 ? _c : col - 1;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
_c = c;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
_c = c + 1;
_c = _c < col ? _c : 0;
if (cells.getCell(_r, _c).isAlive()) {
aliveNeighbourSize++;
}
cell.setAliveNeighbourSize(aliveNeighbourSize);
}
}
// Determine dead or alive.
Cells result = new Cells(cells.getRow(), cells.getCol());
for (int r = 0; r < row; r++) {
for (int c = 0; c < col; c++) {
final Cell cell = cells.getCell(r, c);
final int aliveNeighbourSize = cell.getAliveNeighbourSize();
final boolean alive = cell.isAlive();
final boolean shouldAlive;
if (alive) {
if (aliveNeighbourSize < 2) {
// Any live cell with fewer than two live neighbours dies, as if caused by
// under-population.
shouldAlive = false;
} else if (aliveNeighbourSize == 2 || aliveNeighbourSize == 3) {
// Any live cell with two or three live neighbours lives on to the next generation.
shouldAlive = true;
} else {
// Any live cell with more than three live neighbours dies, as if by over-population.
shouldAlive = false;
}
} else {
if (aliveNeighbourSize == 3) {
// Any dead cell with exactly three live neighbours becomes a live cell, as if by
// reproduction.
shouldAlive = true;
} else {
shouldAlive = false;
}
}
result.getCell(r, c).setAlive(shouldAlive);
}
}
return result;
}
