Other queue implementation in java

               A basic queue is a collection of elements with a front end and rear end. Some of the other types of queue’s are listed below.

PriorityQueue: A queue with priority value associated with it. It dequeued according to the priority. Generally, higher priority is dequeued first.

ArrayDeque : This implementation of queue can be resizable. The elements can be added or removed at both front and back ends.

The java implementations of both queues are given below.

1.Priority Queue implementation in java:

              This program uses the built in packages java.util.PriorityQueue and java.util.Queue.

Steps:

• ·       Develop a class with main() function.
• ·       Create an object for Queue class.
• ·       Insert the data elements to the queue by add() function.
• ·       Deque the elements until the last element and print the queue elements.

Program:

import java.util.PriorityQueue;

import java.util.Queue;

public class PriorityQueueEg {

    public static void main(String[] args) {

        Queue<Integer> priorityQueue1 = new PriorityQueue<>();

        // Enqueue elements

        priorityQueue1.add(310);

        priorityQueue1.add(130);

        priorityQueue1.add(253);

        priorityQueue1.add(454);

        priorityQueue1.add(364);

        // printing the queue elements

        System.out.println("The elements in the PriorityQueue is: " + priorityQueue1);

         // deleting the elements until the queue is empty(Deque)

        while (!priorityQueue1.isEmpty()) {

            System.out.println("The Removed element is: " + priorityQueue1.poll());

        }

    }

}

Output:

C:\raji\blog>javac PriorityQueueEg.java

C:\raji\blog>java PriorityQueueEg

The elements in the PriorityQueue is: [130, 310, 253, 454, 364]

The Removed element is: 130

The Removed element is: 253

The Removed element is: 310

The Removed element is: 364

The Removed element is: 454

Next implementation is given as follows.

ArrayDeque implementation in java:

              This implementation uses the built in packages java.util.ArrayDeque and java.util.Deque.

Steps:

• ·       write a class with main() function.
• ·        Queue class object is created as integer.
• ·       Enque(insert) the data elements to the queue by add() function.
• ·       Delete the elements until the last element and print the queue elements.

Program:

import java.util.ArrayDeque;

import java.util.Deque;

public class ArrayDequeEg {

    public static void main(String[] args) {

        Deque<Integer> deque1 = new ArrayDeque<>();

        // Enqueue(adding) elements at the end

        deque1.addLast(231);

        deque1.addLast(551);

        deque1.addLast(300);

        deque1.addLast(677);    

        // The elements in deque is displayed here

        System.out.println("ArrayDeque: " + deque1);

        // Dequeue(remove) the  elements from the front

        while (!deque1.isEmpty()) {

            System.out.println("Removed element: " + deque1.pollFirst());

        }

    }

}

Output:

C:\raji\blog>javac ArrayDequeEg.java

C:\raji\blog>java ArrayDequeEg

ArrayDeque: [231, 551, 300, 677]

Removed element: 231

Removed element: 551

Removed element: 300

Removed element: 677

These are the other queue implementation in java. Keep coding!!!