001package algs13.xbacktrack.xsudoku; 002 003/** 004 * An immutable cell represents a clue provided in the Sudoku puzzle. 005 * The digit associated with an immutable cell cannot be changed 006 * by the solver. 007 */ 008final class XImmutableCell extends XSudokuCell { 009 010 private final int digit; 011 012 XImmutableCell(final int x, final int y, int digit) { 013 super(x, y); 014 this.digit = digit; 015 } 016 017 @Override 018 int getDigit() { 019 return digit; 020 } 021}