// Program to demonstrate the usage of queues by modeling
//   a line at a deli counter
import java.util.*;

public class DeliLine {
   public static void main(String[] args) {
      Queue<String> customers = new LinkedList<String>();
      getInLine("Caitlin", customers);
      getInLine("Aaron", customers);
      getInLine("Zaha", customers);
      getInLine("James", customers);
      getInLine("Michael", customers);
      System.out.println(customers);
      System.out.println();
      
      serveNext(customers);
      serveNext(customers);
      System.out.println(customers);
      
      // customers.add(0, "Brett");    // no cuts, no buts, no coconuts
      customers.add("Brett");
      System.out.println(customers);
   }
   
   // add a new person to the line
   // pre: customers != null
   public static void getInLine(String person, Queue<String> customers) {
      customers.add(person);
      System.out.println(person + " now in line");
   }
   
   // serve the next person in line
   // pre: customers != null
   public static void serveNext(Queue<String> customers) {
      String next = customers.remove();
      System.out.println("Now serving: " + next);
      
      if (customers.isEmpty()) {
         System.out.println("  No one left.");
      } else {
         // ???
      }
   }
}