package org.kodejava.example.util;
import java.util.LinkedList;
import java.util.Queue;
public class QueueDemo {
public static void main(String[] args) {
// Create an instance of a queue, ere we use the LinkedList class which
// implements the Queue interface. Add some elements to the queue using
// the offer method.
Queue<String> queue = new LinkedList<>();
queue.offer("First visitor");
queue.offer("Second visitor");
queue.offer("Third visitor");
queue.offer("Fourth visitor");
// Let see the size of our queue
System.out.println("Size: " + queue.size());
// The peek and element method read the head of the queue without removing
// the element. The difference is, if the queue is empty peek method
// return null while element method throws a NoSuchElementException
// exception.
System.out.println("Queue head using peek : " + queue.peek());
System.out.println("Queue head using element: " + queue.element());
// The poll method retrieves and then removes the head of the queue.
// On the next code will process all the element of the queue. When no
// item in the queue the poll method will return null.
Object data;
while ((data = queue.poll()) != null) {
System.out.println(data);
}
}
}
The code snippet above print the following output:
Size: 4 Queue head using peek : First visitor Queue head using element: First visitor First visitor Second visitor Third visitor Fourth visitor
Wayan Saryada
Founder at Kode Java Org
I am a programmer, a runner, a recreational diver, currently live in the island of Bali, Indonesia. Mostly programming in Java, Spring Framework, Hibernate / JPA. You can support my works by donating here. Thank you 🙂.
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