Fixed bugs in DotsAndBoxesGrid.java

src/main/java/dotsandboxes/DotsAndBoxesGrid.java

@@ -109,11 +109,11 @@ public class DotsAndBoxesGrid {
         if (x >= width - 1 || x < 0 || y >= height - 1 || y < 0) {
             return false;
         }
-
-        // A box is complete if the north and south horizontals and the east and west verticals have all been drawn.
-        // FIXME: You'll need to fix this code (after writing a test first).
+        if (horizontals[x][y] && horizontals[x][y+1] && verticals[x][y] && verticals[x+1][y]) {
 			return true;		  
 		}
+        return false;
+    }
 
     /** Tries to claim a box for a player. If the box is complete, sets the ownership and returns true. */
     private boolean claimBox(int x, int y, int p) {
@@ -138,8 +138,10 @@ public class DotsAndBoxesGrid {
         if (y >= height || y < 0) {
             throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height));
         }
+        if (horizontals[x][y]) {
+			throw new IllegalStateException("The line already exists, try again");  
+		}
 
-        // FIXME: You need to throw an exception if the line was already drawn.
 
         this.horizontals[x][y] = true;
 
@@ -169,8 +171,10 @@ public class DotsAndBoxesGrid {
         if (y >= height - 1 || y < 0) {
             throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height - 1));
         }
+        if (verticals[x][y]) {
+			throw new IllegalStateException("The line already exists, try again");  
+		}
 
-        // You need to throw an exception if the line was already drawn.
 
         this.verticals[x][y] = true;
         // Try to claim the north or south boxes