/* KeyPadLock1.java
** Author: R. McCloskey  and  < your name >
** Date: October 2019
**
** An instance of this class models a locking device that can be either 
** open or closed; to open it requires that a prescribed sequence of digits
** be entered on its keypad.
*/

public class KeyPadLock1 implements KeyPadLock {

   // class constant
   // --------------
   protected final int MIN_CODE_LENGTH = 4;

   // instance variables
   // ------------------
   protected int[] secretCode;    // holds the code needed to open the lock
   protected int[] digitsEntered; // holds the most recently entered digits

   // **********************************************************
   // Declaring one or more other instance variables is advised.
   // **********************************************************


 
   // constructors
   // ------------

   /* Initializes this KeyPadLock so that it is closed and so that its 
   ** "secret code" (i.e., the sequence of digits needed to open it) 
   ** corresponds to the contents of the given array (which is assumed 
   ** to hold one digit per element).  If the length of the given array 
   ** is less than four, an IllegalArgumentException is thrown.
   */
   public KeyPadLock(int[] code) { 
      // STUB
   }


   // observers
   // ---------

   /* Reports whether or not the lock is currently open.
   */
   public boolean isOpen() { return false; }   // STUB


   // mutators
   // --------

   /* Records that the given digit has been entered on the keypad.  An
   ** IllegalArgumentException is thrown if digit is not in the range 0..9.
   */
   public void enterDigit(int digit) { 
      if (digit < 0  ||  digit > 9) {
         throw new IllegalArgumentException("digit must be between 0 and 9");
      }

      // ******************
      // Missing code here.
      // ******************
   }


   /* If the lock is already open, it remains so.  Otherwise, if the digits 
   ** most recently entered on the keypad match the secret code, the lock 
   ** becomes open and the memory of recently entered digits is wiped clean.
   ** Otherwise, the lock remains closed.
   */
   public void open() {  
      // STUB
   }


   /* Closes the lock, if it wasn't already.
   */
   public void close() { 
      // STUB 
   }

}