New interface

app/src/main/java/sudoku/Solver.java

@@ -24,7 +24,7 @@ public class Solver implements SudokuSolver {
     /**
      * Resets the board to all zeros
      */
-    public void reset() {
+    public void clear() {
         board = new int[9][9];
     }
 
@@ -63,7 +63,7 @@ public class Solver implements SudokuSolver {
 
         // Check for legal values in the current cell
         for (int val = 1; val <= 9; ++val) {
-            if (legal(row, col, val)) {
+            if (isLegal(row, col, val)) {
                 board[row][col] = val;
                 // When we find a legal value, recursively call solve() on the next cell
                 if (solve(row + 1, col)) {
@@ -80,25 +80,21 @@ public class Solver implements SudokuSolver {
      * Randomizes the board. This guarantees a solvable board.
      */
     public void randomizeBoard() {
-        this.reset();
+        this.clear();
         for (int i = 0; i < 9; ++i) {
             int row = (int) (Math.random() * 9);
             int col = (int) (Math.random() * 9);
             int val = (int) (Math.random() * 9) + 1;
-            if (legal(row, col, val)) {
+            if (isLegal(row, col, val)) {
                 board[row][col] = val;
             }
         }
     }
 
     /**
-     * Sets the value of the board at the given position
+     * {@inheritDoc}
-     * 
-     * @param row row to set
-     * @param col column to set
-     * @param val value to set
      */
-    public void setPos(int row, int col, int val) {
+    public void set(int row, int col, int val) {
         if (row < 9 && col < 9) {
             board[row][col] = val;
         }
@@ -107,7 +103,17 @@ public class Solver implements SudokuSolver {
     /**
      * {@inheritDoc}
      */
-    public boolean legal(int row, int col, int val) {
+    public int get(int row, int col) {
+        if (row < 9 && col < 9) {
+            return board[row][col];
+        }
+        return 0;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public boolean isLegal(int row, int col, int val) {
         if (row < 0 || row >= 9 || col < 0 || col >= 9 || val < 1 || val > 9) {
             return false;
         }

app/src/main/java/sudoku/SudokuSolver.java

@@ -3,11 +3,14 @@ package sudoku;
 public interface SudokuSolver {
     /**
      * Set sudoku board, numbers 1-9 are fixed values, 0 is unsolved.
+     * 
+     * @param board a board to copy values from
+     * @throws IllegalArgumentException if board is invalid, e.g. not 9x9
      */
     void setBoard(int[][] board);
 
     /**
-     * Get the sudoku board
+     * Get a copy of the sudoku board
      */
     int[][] getBoard();
 
@@ -26,5 +29,28 @@ public interface SudokuSolver {
      * @param nbr
      * @return true if legal
      */
-    boolean legal(int row, int col, int nbr);
+    boolean isLegal(int row, int col, int nbr);
+
+    /**
+     * Get number on board
+     * 
+     * @param row
+     * @param col
+     * @return number on board
+     */
+    int get(int row, int col);
+
+    /**
+     * Set number on board, numbers 1-9 are fixed values, 0 is unsolved.
+     * 
+     * @param row
+     * @param col
+     * @param nbr
+     */
+    void set(int row, int col, int nbr);
+
+    /**
+     * Clear the board
+     */
+    void clear();
 }

app/src/test/java/sudoku/SolverTest.java

@@ -31,17 +31,17 @@ class SolverTest {
     @Test
     void legalTest() {
         Solver solver = new Solver();
-        assertTrue(solver.legal(0, 0, 1));
+        assertTrue(solver.isLegal(0, 0, 1));
-        solver.setPos(0, 0, 1);
+        solver.set(0, 0, 1);
 
         IntStream.range(0, 9).forEach(i -> {
-            assertFalse(solver.legal(0, i, 1));
+            assertFalse(solver.isLegal(0, i, 1));
-            assertFalse(solver.legal(i, 0, 1));
+            assertFalse(solver.isLegal(i, 0, 1));
         });
 
-        assertTrue(solver.legal(5, 5, 1));
+        assertTrue(solver.isLegal(5, 5, 1));
-        assertTrue(solver.legal(8, 8, 9));
+        assertTrue(solver.isLegal(8, 8, 9));
-        assertTrue(solver.legal(8, 8, 1));
+        assertTrue(solver.isLegal(8, 8, 1));
     }
 
     @Test
@@ -51,7 +51,7 @@ class SolverTest {
         assertTrue(solver.solve());
         assertTrue(solver.isSolved());
 
-        solver.reset();
+        solver.clear();
         solver.randomizeBoard();
         assertFalse(solver.isSolved());
         assertTrue(solver.solve());
@@ -62,25 +62,25 @@ class SolverTest {
         Solver solver = new Solver();
         assertTrue(solver.solve());
         solver.randomizeBoard();
-        solver.reset();
+        solver.clear();
         assertFalse(solver.isSolved());
     }
 
     @Test
     void legalWithInvalidInputsTest() {
         Solver solver = new Solver();
-        assertFalse(solver.legal(-1, 0, 1));
+        assertFalse(solver.isLegal(-1, 0, 1));
-        assertFalse(solver.legal(0, -1, 1));
+        assertFalse(solver.isLegal(0, -1, 1));
-        assertFalse(solver.legal(0, 0, -1));
+        assertFalse(solver.isLegal(0, 0, -1));
-        assertFalse(solver.legal(0, 0, 10));
+        assertFalse(solver.isLegal(0, 0, 10));
     }
 
     @Test
     @Disabled
     void unsolvableTest() {
         Solver solver = new Solver();
-        solver.setPos(0, 0, 1);
+        solver.set(0, 0, 1);
-        solver.setPos(0, 1, 1);
+        solver.set(0, 1, 1);
         assertFalse(solver.solve());
     }
 }