/* 
 * BoundedBufferCSem.java (Implements Consumer Using Semaphores).
 *
 * Written by : Nitin  Motgi (nmotgi@cs.ucf.edu)
 *
 * This file implements consumer using semaphores.This puts the data 
 * into the buffer and other side which is consumer removes from it.
 * The buffer has finite size so the producer has to wait when it's
 * full, and the consumer has to wait when it's empty. And, of course
 * all elements added to the queue by the producer must be seen by 
 * the consumer exactly once.
 * 
 * Portions copyright(c) 2000 to School of Electrical Engineering and 
 * Computer Science, UCF, Orlando.                   
 *
 * Use and distribution of this source code are strictly governed by 
 * terms and conditions set by the authors.
 * 
 * $Id : BoundedBufferCSem.java, v1.0.0 02/07/2001. $
 *
 * Revision History Revisited:
*/

/* Start of BoundedBufferPSem.*/
public class BoundedBufferCSem extends Thread{
  /* Each consumer is given an ID so that the higher level
     routine can interact with a specific processor.*/
     int nID;

  /* This is up level pointer points to the parent class
     which provides mechanism for synchronization.*/
     BoundedBufferSem BBSem;

  /* End condition indicator set to push the Producer from
     endlessly producing an item and put in the queue.*/
     boolean bEndCondition;


     /* 
      * This function is constructor for this class.
      */
     public BoundedBufferCSem(int nID,BoundedBufferSem BBSem){
       this.nID   = nID;                  /* Store ID.*/
       this.BBSem = BBSem;                /* Pointer to Higher class.*/
       bEndCondition = true;              /* Produce one item and put in
                                             shared data structure.*/
     }/* End of BoundedBufferCSem.*/

     /*
      * This program is heart of this thread.
      */
     public void run(){
         int nItem;

         /* Till the indicator turns false.*/
         while(bEndCondition){
          BBSem.Block.P();
          if(BBSem.ConsumeCheck() == true){
           BBSem.Block.V();
           break;
          }/* End if.*/

          BBSem.Full.P();
          BBSem.Mutex.P();

          BBSem.GetItem();
          
          BBSem.Mutex.V();
          BBSem.Empty.V();
          BBSem.ConsumeItem(1,this);
          BBSem.Block.V();
         }/* End of while.*/
      }/* End of run.*/

      /*
       * Sets the end codition to true or false.
       */
      public void SetEndCondition(boolean bState){
        bEndCondition = bState;
      }/* End of SetEndCondition.*/

}/* End of BoundedBufferCSem.*/