// This class define the tree node.

public class Node
{
   public final static int Black = 0;    // constants used to define the 
   public final static int Red = 1;      // node color
   public final static int Left_son = 2; // constants used to identify
   public final static int Right_son = 3;// the node parent and sons. 
   public final static int Parent = 4;
   public final static int Bold = 5;     // constants used to define
   public final static int Reg = 6;      // the node presentation.

   private int  color;
   private int  key;
   private Node L,R,P;      // L-left son,R-right son,P-parent
   private int  bold;
   private int  LocX;       // location of the node on the display
   private int  LocY;       // they could change exch time the tree redraw.

   // constructor create a new node the default color is red
   // the default appearance (bold) is regular.
   // initialize the key field.

   public Node(int k)
   {
      color = Red;
      key = k;
      L = null;
      R = null;
      P = null;
      bold = Reg;
   }

   // constructor for constructing a tree null object, is color
   // is black. 

   public Node()     
   {
      color = Black;
      key = -1;
      L = null;
      R = null;
      P = null;
   }

   // This method set the node key.

   public void setKey(int k)
   {
      key = k;
   }

   // This method return the node key.

   public int getKey()
   {
      return (key);
   }
    
   // This method set the node color.

   public void setColor(int c)
   {
      if (c == Black)
         color = Black;
      else
         if (c == Red)
            color = Red;
   }

   // This method return the node color.

   public int getColor()
   {
      return (color);
   }

   // This method set the node parent or childs acording to the who
   // parameter.

   public void setNode(int who,Node n)
   {
      switch (who)
      {
          case Left_son:
               L = n;   
               break;
          case Right_son:
               R = n;
               break;
          case Parent:
               P = n;
               break;
      }
   }

   // This method return the node parent or childs acording to the who
   // parameter.

   public Node getNode(int who)
   {
      switch (who)   
      {
          case Left_son: 
               return (L);
          case Right_son:
               return (R);
          case Parent:
               return (P);
      }
      return (null);
   }

   // This method set the appearance of the node acording to the b
   // parameter.

   public void setBold(int b)
   {
      switch (b)
      {
         case Bold:
                   bold = Bold;
                   break; 
         case Reg:
                   bold = Reg;
                   break;
      }
   }

   // This method return true if the node appearance is Bold.

   public boolean isBold()   
   {
      if (bold == Bold)
         return (true);
      return (false);
   }
              
   // This method return the current X location of the node on the
   // display.
     
   public int getLocX()
   {
      return LocX;
   }   

   // This method return the current Y location of the node on the
   // display

   public int getLocY()
   {
      return LocY;
   }
  
   // This method setthe X location of the node on the display.

   public void setLocX(int x)
   {
      LocX = x;
   }
 
   // This method setthe Y location of the node on the display.

   public void setLocY(int y)
   {
      LocY = y;
   }
}