Board.java

/** 
 * Board.java
 *
 * @author Martin Klöckner, Daniel Höpfl
 */

package SpringerPack;

/**
 * class which saves the data while Backtracking
 * it also implements a locking-mechanism, because of
 * the thread of the calculation the output thread
 * could access the fields at the same time which cause
 * a wrong output on the board on the screen.
 */
public class Board {
   private int mSize;
   private int mFeld[][] = null;

   public Board(int inSize)
   {
      mSize = inSize;
      if(mSize < 5)
         mSize = 5;

      mFeld = new int[mSize+4][mSize+4];
   
      for(int x=0;x < mSize; x++)
         for(int y=0; y < mSize; y++)
            setXY(x, y, 0);

      for(int i=-2;i < mSize+2;i++)
      {
            // left
         setXY(-1, i, -1);
         setXY(-2, i, -1);

            // up
         setXY(i, -1, -1);
         setXY(i, -2, -1);

            // right
         setXY(mSize+0, i, -1);
         setXY(mSize+1, i, -1);

            // down
         setXY(i, mSize+0, -1);
         setXY(i, mSize+1, -1);
      }
   }
   
   /**
    * InnerClass which solves the locking-problem, described above
    */
   class mInnerLockClass {
      int mLocked = 0;
      public synchronized boolean setLock()
      {
         if(mLocked == 0)
         {
            mLocked++;

            return true;
         }
         return false;
      }

      public synchronized void unsetLock()
      {
         mLocked--;
      }
   };
   
   private mInnerLockClass mBoardLock = new mInnerLockClass();

   /**
    * locks the board. so nobody can access data, after this call
    */
   public void lockBoard()
   {
      while(!mBoardLock.setLock())
         ;
   }

   /**
    * unlocks the board. everybody is able again to access the data of the Board-class.
    */
   public void unlockBoard()
   {
      mBoardLock.unsetLock();
   }

   /**
    * sets the value on a postion.
    * 
    * @param inX      X-coordinate of the data
    *
    * @param inY      Y-coordinate of the data
    *
    * @param inValue   value which is set
    */
    
   public void setXY(int inX, int inY, int inValue)
   {
      if(inX < -2 ||
         inY < -2 ||
         inX > mSize+1 ||
         inY > mSize+1)
      {
         return;
      }

      mFeld[inX+2][inY+2] = inValue;
   }

   /**
    * returns the value of a postion
    *
    * @param inX      X-coordinate of the data
    *
    * @param inY      Y-coordinate of the data
    */
   public int getXY(int inX, int inY)
   {
      if(inX < -2 ||
         inY < -2 ||
         inX > mSize+1 ||
         inY > mSize+1)
      {
         return -1;
      }

      return mFeld[inX+2][inY+2];
   }
}