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Java Java Data Structures - Retired Efficiency! Call Center Queue

Jvalant Dave
Jvalant Dave
4,483 Points
Posted by Jvalant Dave
Jvalant Dave
4,483 Points

Having trouble with the next challenge (Call center) ?

I seem to have the correct code for the challenge (based on another discussion question that has the same answer as me) but I keep getting a "Did you remember to call the assist method on the Customer Service Rep" message. I have tried refreshing the code challenge and I'm still getting the same message, even though I have called the assist method. Here is my code: 

 /********************************************
 * 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
 ********************************************
 */
csr = mSupportReps.poll();
while ((csr = mSupportReps.poll()) == null){
  playHoldMusic();
}
/********************************************
 * TODO (2) 
 * After we have assigned the rep, call the 
 * assist method and pass in the customer
 ********************************************
 */
csr.assist(customer);

/********************************************
 * TODO (3) 
 * Since the customer support rep is done with
 * assisting, put them back into the queue.
 ********************************************
 */
mSupportReps.add(csr);
Jvalant Dave
Jvalant Dave
4,483 Points
Jvalant Dave
Jvalant Dave
4,483 Points

I commented out the csr = mSupportReps.poll() line above the while loop and it worked! Not sure why, I guess the line was unnecessary but not sure why I was getting an failure on the challenge because of it...

4 Answers

Florian Tönjes
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Florian Tönjes
Full Stack JavaScript Techdegree Graduate 50,856 Points
Florian Tönjes
.a{fill-rule:evenodd;}techdegree seal-36
Florian Tönjes
Full Stack JavaScript Techdegree Graduate 50,856 Points

Hey Jvalant,

the code failed because it removed the first csr from the queue, without letting him support a customer, and then never touching him again.

Regards, Florian

Jeff Wilton
Jeff Wilton
16,646 Points
Jeff Wilton
Jeff Wilton
16,646 Points

You were very close, just remove this line - which was causing things to happen out of order.

csr = mSupportReps.poll();
Kourosh Raeen
Kourosh Raeen
23,733 Points
Kourosh Raeen
Kourosh Raeen
23,733 Points

I agree with Florian Tönjes. If you want to keep the line before the loop change your code to:

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;
    /********************************************
     * 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
     ********************************************
     */
    csr = mSupportReps.poll();
    while (csr == null) {
      playHoldMusic();
      csr = mSupportReps.poll();
    }
    /********************************************
     * TODO (2) 
     * After we have assigned the rep, call the 
     * assist method and pass in the customer
     ********************************************
     */

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

  }

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

}
Jvalant Dave
Jvalant Dave
4,483 Points
Jvalant Dave
Jvalant Dave
4,483 Points

Thanks guys! I understand why that line was incorrect now.