package me.ramswaroop.common;
import java.util.NoSuchElementException;
/**
* Created by IntelliJ IDEA.
* User: ramswaroop
* Date: 4/12/15
* Time: 11:07 AM
* To change this template go to Preferences | IDE Settings | File and Code Templates
*/
public class LinkedQueue<E> implements Queue<E> {
Node<E> front;
Node<E> rear;
public LinkedQueue() {
front = null;
rear = null;
}
@Override
public E add(E item) {
if (front == null || rear == null) {
front = rear = new Node<>(item, null);
} else {
rear.next = new Node<>(item, null);
rear = rear.next;
}
return item;
}
@Override
public E remove() {
if (rear.next == front) {
throw new NoSuchElementException();
}
E item = element();
front = front.next;
return item;
}
@Override
public E element() {
if (front == null) {
throw new NoSuchElementException();
}
return front.item;
}
@Override
public int size() {
int count = 0;
if (rear.next == front) return count;
for (Node node = front; node != rear; node = node.next) {
count++;
}
return count;
}
@Override
public boolean isEmpty() {
return rear.next == front;
}
@Override
public void print() {
Node<E> node;
System.out.print("[");
if (rear.next == front) {
System.out.println("]");
return;
}
for (node = front; node != rear; node = node.next) {
System.out.print(node.item + ",");
}
System.out.println(node.item + "]");
}
private class Node<E> {
E item;
Node<E> next;
public Node(E item, Node<E> next) {
this.item = item;
this.next = next;
}
}
}