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Java Java Data Structures - Retired Efficiency! Queueing

Miguel Angel Rodriguez
Miguel Angel Rodriguez
11,280 Points

Need help with the code challenge

Im stuck with the code challenge, please help me. I write the code but the message show me "Try again" error.

import java.util.ArrayDeque; import java.util.Queue;

public class CallCenter { Queue<CustomerSupportRep> mSupportReps;

public CallCenter(Queue<CustomerSupportRep> queue) { mSupportReps = queue; }

public void acceptCustomer(Customer customer) { CustomerSupportRep csr; while ((csr = mSupportReps.poll()) != null) { csr.assist(customer); if (csr.getAssistedCustomers().contains(customer)) { mSupportReps.add(csr); } } playHoldMusic();

/********************************************
 * TODO (1) 
 * Wait until there is an available rep in the queue.
 * While there is not one available, playHoldMusic
 * HINT: That while assignmentcheck loop syntax we used to 
  *      read files seems pretty similar
 ********************************************
 */

/********************************************
 * TODO (2) 
 * After we have assigned the rep, call the 
 * assist method and pass in the customer
 ********************************************
 */

/********************************************
 * TODO (3) 
 * Since the customer support rep is done with
 * assisting, put them back into the queue.
 ********************************************
 */

}

public void playHoldMusic() { System.out.println("Smooooooth Operator....."); }

}

Miguel Angel Rodriguez
Miguel Angel Rodriguez
11,280 Points
import java.util.ArrayDeque;
import java.util.Queue;

public class CallCenter {
  Queue<CustomerSupportRep> mSupportReps;

  public CallCenter(Queue<CustomerSupportRep> queue) {
    mSupportReps = queue;
  }

  public void acceptCustomer(Customer customer) {
    CustomerSupportRep csr;
    while ((csr = mSupportReps.poll()) != null) {
      csr.assist(customer);
      if (csr.getAssistedCustomers().contains(customer)) {
        mSupportReps.add(csr);
      }
    }
    playHoldMusic();

    /********************************************
     * TODO (1) 
     * Wait until there is an available rep in the queue.
     * While there is not one available, playHoldMusic
     * HINT: That while assignmentcheck loop syntax we used to 
      *      read files seems pretty similar
     ********************************************
     */

    /********************************************
     * TODO (2) 
     * After we have assigned the rep, call the 
     * assist method and pass in the customer
     ********************************************
     */

    /********************************************
     * TODO (3) 
     * Since the customer support rep is done with
     * assisting, put them back into the queue.
     ********************************************
     */

  }

  public void playHoldMusic() {
    System.out.println("Smooooooth Operator.....");
  }

}

1 Answer

Dan Johnson
Dan Johnson
40,533 Points

mSupportReps not being null means someone is available to assist, so you'll want to check for the opposite:

// While there are no support reps ready
while((csr = mSupportReps.poll()) == null) {
    // Continue to play the hold music
    playHoldMusic(); 
}

If the loop stops that means someone got selected, so we can use csr:

// Assist the customer
csr.assist(customer);
// Move back into the queue since they've finished assisting
mSupportReps.add(csr);