You have been given an implementation of a stack and of a queue based on linked

Question

You have been given an implementation of a stack and of a queue based on linked elements. These implementations do not include precondition checks and do not throw any exceptions. This question is about correcting this.You must create a new unchecked exception type, respectively called EmptyQueueException.

Queue.java

public interface Queue<E> {
   public boolean isEmpty();

   public void enqueue(E o);

   public E dequeue();
}

LinkedQueue.java

public class LinkedQueue<E> implements Queue<E> {

   private static class Elem<T> {

       private T value;
       private Elem<T> next;

       private Elem(T value, Elem<T> next) {
           this.value = value;
           this.next = next;
       }
   }

   private Elem<E> front;
   private Elem<E> rear;

   public E peek() {
       return front.value;
   }

   public void enqueue(E o) {
       Elem<E> newElem;
       newElem = new Elem<E>(o, null);

       if (rear == null) {
           front = rear = newElem;
       } else {
           rear.next = newElem;
           rear = newElem;
       }
   }

   public E dequeue(){
E result = front.value;
if ( front != null & front.next == null ) {
front = rear = null;
} else {
front = front.next;
}
return result;
}

   public boolean isEmpty() {
return front == null;
}
   public static void main(String[]args){
       LinkedQueue<String> q=new LinkedQueue<String>();
       q.isEmpty();
   }
}

Explanation / Answer

Please find the corrected code below :

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