Implementing hashing capabilities to the Board class.

src/Assignments/A1/models/Board.java

@@ -1,5 +1,7 @@
 package Assignments.A1.models;
 
+import java.util.Arrays;
+
 /**
  * This class keeps track of the current state (whether in permutation or not) of the board.
  *
@@ -8,7 +10,7 @@ package Assignments.A1.models;
  */
 public class Board {
 
-    private final Piece[] pieces;
+    private Piece[] pieces;
 
     /**
      * Default constructor that generates the solved board.
@@ -26,18 +28,24 @@ public class Board {
     /**
      * Constructor used to create a board with a pre-provided board.
      *
-     * @precondition board.length == 9
+     * @precondition board != null
      * @postcondition a board is created with given locations
      *
      * @param board the provided state of the board.
      */
-    public Board(Piece[] board) {
+    public Board(Board board) {
-        if (board.length != 9) {
+        if (board == null) {
-            throw new IllegalArgumentException("The board must be a array size of 9.");
+            throw new IllegalArgumentException("The board must be valid an initialized.");
+        }
+        this.pieces = new Piece[9];
+        for (int index = 0; index < 9; index++) {
+            if (board.getPiece(index) != null) {
+                this.pieces[index] = new Piece(board.getPiece(index));
+            }
         }
-        this.pieces = board;
     }
 
+
     /**
      * Checks the status of a place on the board. If the location is taken or not.
      *
@@ -88,6 +96,103 @@ public class Board {
         throw new IllegalStateException("The state of the board must have 1 empty space.");
     }
 
+    /**
+     * Takes two values on the board and swaps them if possible.
+     *
+     * @precondition board.get(first).validMove(second) == true
+     *            || board.get(second).validMove(first) == true
+     * @postcondition the values are swapped
+     *
+     * @param first the first index of the values being swapped
+     * @param second the second index of the values being swapped
+     * @return if the values were swapped or not.
+     */
+    public boolean swap(int first, int second) {
+        // Checks if the first piece is empty and the second is not.
+        if (this.pieces[first] == null && this.pieces[second] != null) {
+            // Checks if the moves are valid
+            if (this.pieces[second].validMove(first, this)) {
+                // Swaps the values
+                this.pieces[first] = this.pieces[second];
+                this.pieces[second] = null;
+                return true; // Successful Swap
+            }
+        } else if (this.pieces[second] == null && this.pieces[first] != null) { // Checks the inverse.
+            // Checks if the moves are valid
+            if (this.pieces[first].validMove(second, this)) {
+                // Swaps the values
+                this.pieces[second] = this.pieces[first];
+                this.pieces[first] = null;
+                return true; // Successful Swap
+            }
+        }
+        return false;
+    }
+
+    /**
+     *
+     * @return
+     */
+    @Override
+    public int hashCode() {
+        int[] hashValues = new int[9];
+
+        for (int i = 0; i < 9; i++) {
+            if (this.pieces[i] != null) {
+                hashValues[i] = this.pieces[i].getValue();
+            } else {
+                hashValues[i] = 0;
+            }
+        }
+
+        return Arrays.hashCode(hashValues);
+    }
+
+    /**
+     * Checks if this and the other object are the same.
+     * @precondition none
+     * @postcondition they are compared.
+     *
+     * @param o the other object.
+     * @return if they are the same, True
+     *         if they are not,      False
+     */
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) {
+            return true;
+        }
+        if (o == null) {
+            return false;
+        }
+        if (this.getClass() != o.getClass()) {
+            return false;
+        }
+        Board other = (Board) o;
+        for (int i = 0; i < 9; i++) {
+            if (this.pieces[i].getValue() != other.pieces[i].getValue()
+                || this.pieces[i].getLoc() != other.pieces[i].getLoc()) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    /**
+     * Specifies a way of printing out the board with its current state.
+     * @return the current state formatted.
+     */
+    @Override
+    public String toString() {
+        String result = "";
+        for (int i = 0; i < 9; i++) {
+            result += i + " ";
+            if ((i+1) % 3 == 0) {
+                result += "\n";
+            }
+        }
+        return result;
+    }
 
     /* Private Methods Below. End of Java Docs. */