Java Deque and ArrayDeque Examples

The ArrayDeque class provides the facility of using deque and resizable-array. It inherits the AbstractCollection class and implements the Deque interface.

Read more at https://www.javaguides.net/2018/08/collections-framework-the-deque-interface.html

Java ArrayDeque Examples

Example 1 - Java ArrayDeque Example

import java.util.ArrayDeque;
import java.util.Deque;

public class ArrayDequeExample {
    public static void main(String[] args) {
     // Creating Deque and adding elements
     Deque<String> deque = new ArrayDeque<String>();
     deque.add("element1");
     deque.add("element2");
     deque.add("element3");
     // Traversing elements
     for (String str : deque) {
        System.out.println(str);
     }
   }
}

Output:

element1
element2
element3

Example 2 - Java ArrayDeque Example: offerFirst() and pollLast()

import java.util.ArrayDeque;
import java.util.Deque;

public class DequeExample {
    public static void main(String[] args) {
        Deque < String > deque = new ArrayDeque < String > ();
        deque.offer("element1");
        deque.offer("element2");
        deque.add("element3");
        deque.offerFirst("element4");
        System.out.println("After offerFirst Traversal...");
        for (String s: deque) {
            System.out.println(s);
        }
        // deque.poll();
        // deque.pollFirst();//it is same as poll()
        deque.pollLast();
        System.out.println("After pollLast() Traversal...");
        for (String s: deque) {
            System.out.println(s);
        }
    }
}

Output:

After offerFirst Traversal...
element4
element1
element2
element3
After pollLast() Traversal...
element4
element1
element2

Example 3 - Java ArrayDeque Example: Book Class

import java.util.ArrayDeque;
import java.util.Deque;

class Book {
    int id;
    String name, author, publisher;
    int quantity;

    public Book(int id, String name, String author, String publisher, int quantity) {
        this.id = id;
        this.name = name;
        this.author = author;
        this.publisher = publisher;
        this.quantity = quantity;
    }
}

public class ArrayDequeExample1 {
    public static void main(String[] args) {
        Deque<Book> set = new ArrayDeque<Book>();
        // Creating Books
        Book b1 = new Book(101, "Let us C", "Yashwant Kanetkar", "BPB", 8);
        Book b2 = new Book(102, "Data Communications & Networking", "Forouzan", "Mc Graw Hill", 4);
        Book b3 = new Book(103, "Operating System", "Galvin", "Wiley", 6);
        // Adding Books to Deque
        set.add(b1);
        set.add(b2);
        set.add(b3);
        // Traversing ArrayDeque
        for (Book b : set) {
            System.out.println(b.id + " " + b.name + " " + b.author + " " + b.publisher + " " + b.quantity);
        }
    }
}

Output:

101 Let us C Yashwant Kanetkar BPB 8
102 Data Communications & Networking Forouzan Mc Graw Hill 4
103 Operating System Galvin Wiley 6

Reference

https://www.javaguides.net/2018/08/collections-framework-the-deque-interface.html