Question

See all photos + Add to a ♡ Search Edit & Create Share . Benny the Barber owns a one-chair shop. They told Benny that customers are not happy with waiting in lines and not get processed in order they arrived. As computer scientist, you are going to help Benny to write a Java program to manage waiting lines and to process customers in the same order they arrive. Here are the functional requirements of the program: • The program shall allow to add a customer to waiting line The program will guarantee that customers will be processed in the same order they arrive When the Barber wants to serve to next customer, the program shall give the name of next customer in line You are asked to implement queue using Linked List data structure, name your class as LinkedQueue BarberShop class has a linked queue field in its state

USE JAVA PROGRAMMING LANGUAGE

Answer 1

// Assuming Customer class is defined
// LinkedQueue.java : Java program to create a Queue using LinkedList

import java.util.NoSuchElementException;

public class LinkedQueue {
  
   // inner class Node representing the Node of the LinkedQueue where data contains Customer and next is the Node to the next Customer
   private class Node
   {
       Customer data;
       Node next;
      
       public Node(Customer inData)
       {
           data = inData;
           next = null;
       }
      
       public Customer toString()
       {
           return(data.toString());
       }
   }
  
   private Node head; // start of queue
   private Node tail; // end of queue
  
   // constructor to create an empty Queue
   public LinkedQueue()
   {
       head = null;
       tail = null;
   }
  
   // method to insert the Customer at the end of the queue
   public void enqueue(Customer data)
   {
       if(data != null)
       {
           Node node = new Node(data);
           if(isEmpty())
           {
               head = node;
               tail = node;
           }else
           {
               tail.next =node;
               tail = node;
           }
       }
   }

   // method to remove and return the Customer at the front of the Queue
   public Customer dequeue() throws NoSuchElementException
   {
       if(!isEmpty())
       {
           Customer item = head.data;
           head = head.next;
           if(head == null)
               tail = null;
           return item;
       }
      
       throw new NoSuchElementException();
   }
  
   // method to return the Customer at the front of the queue
   public Customer getFront() throws NoSuchElementException
   {
       if(!isEmpty())
       {
           return head.data;
       }
      
       throw new NoSuchElementException();
   }
  
   // method to return the String representation of the queue
   public String toString()
   {
       String queueStr = "";
       Node curr = head;
       while(curr != null)
       {
           queueStr += (curr.toString()+"\n");
           curr = curr.next;
       }
      
       return queueStr;
   }
  
   // method to return true if the queue is empty else false
   public boolean isEmpty(){return (head == null);}  

}

//end of LinkedQueue.java