package collectionQueue;

import java.util.LinkedList;
import java.util.Queue;

public class MainQueue {

	public static void main(String[] args) {

		System.out.println("\nQueue in Java\n");
		System.out.println("-----------------------\n");
		System.out.println("Adding items to the Queue");
		// Creating queue would require you to create instannce of LinkedList
		// and assign
		// it to Queue
		// Object. You cannot create an instance of Queue as it is abstract
		Queue<String> queue = new LinkedList<String>();

		
		// Queue with a limited number of elements.
		//
		//Queue<String> queueTwo = new ArrayBlockingQueue<String>(2);
		// queueTwo.offer("hi");
		// queueTwo.offer("there");
		// queueTwo.offer("you");
		// for(String x: queueTwo)
		// System.out.println(x);
		
		
		
		// you add elements to queue using add method
		queue.add("Java");
		queue.add("has");

		queue.add("its own");
		queue.add("Queue");
		queue.add("Interface");

		System.out.println("\nItems in the queue..." + queue + "\n");

		// You remove element from the queue using .remove method
		// This would remove the first element added to the queue, here Java
		System.out.println("remove element: " + queue.remove() + "\n");

		// .element() returns the current element in the queue, here when "java"
		// is removed
		// the next most top element is "has", so "has" would be printed.
		System.out.println("retrieve element: " + queue.element() + "\n");

		// .poll() method retrieves and removes the head of this queue
		// or return null if this queue is empty. Here "has" would be printed and
		// then would
		// be removed
		// from the queue
		System.out.println("remove and retrieve element, null if empty: "
				+ queue.poll() + "\n");

		// .peek() just returns the current element in the queue, null if empty
		// Here it will print "its own" as "has" is removed above.
		System.out.println("retrieve element, null if empty: " + queue.peek()
				+ "\n");
	}
}