Java Program to Implement ArrayDeque API
Last Updated :
19 Jan, 2021
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The ArrayDeque in Java provides how to use resizable-array additionally to the implementation of the Deque interface. It is also referred to as Array Double Ended Queue or Array Deck. This is a special quite array that grows and allows users to feature or remove a component from each side of the queue.
java.lang.Object
java.util.AbstractCollection<E>
java.util.ArrayDeque<E>
All implemented interfaces of ArrayDeque in the hierarchy are:
- Serializable,
- Cloneable,
- Iterable<E>,
- Collection<E>
- Deque<E>
- Queue<E>
Array deques haven't any capacity restrictions; they grow as necessary to support usage. They are not thread-safe; within the absence of external synchronization, they are doing not support concurrent access by multiple threads. Null elements are prohibited. This class is probably going to be faster than Stack when used as a stack, and faster than LinkedList when used as a queue.
Implementation:
// Java program to demonstrate implementation
// of ArrayDeque
import java.util.*;
public class ArrayDequeExample {
public static void main(String[] args)
{
// Initializing an deque
Deque<Integer> de_que = new ArrayDeque<Integer>(10);
// add() method to insert
de_que.add(10);
de_que.add(20);
de_que.add(30);
de_que.add(40);
de_que.add(50);
for (Integer element : de_que) {
System.out.println("Element : " + element);
}
System.out.println("Using clear() ");
// clear() method
de_que.clear();
// addFirst() method to insert at start
de_que.addFirst(564);
de_que.addFirst(291);
// addLast() method to insert at end
de_que.addLast(24);
de_que.addLast(14);
System.out.println(
"Above elements have been cleared");
// Iterator() :
System.out.println(
"Elements of deque using Iterator :");
for (Iterator itr = de_que.iterator();
itr.hasNext();) {
System.out.println(itr.next());
}
// descendingIterator() : to reverse the deque order
System.out.println(
"Print elements in reverse order :");
for (Iterator dItr = de_que.descendingIterator();
dItr.hasNext();)
{
System.out.println(dItr.next());
}
// element() method : to get Head element
System.out.println(
"\nHead Element using element(): "
+ de_que.element());
// getFirst() method : to get Head element
System.out.println(
"Getting Head Element using getFirst(): "
+ de_que.getFirst());
// getLast() method : to get last element
System.out.println(
"Getting Last Element using getLast(): "
+ de_que.getLast());
// toArray() method :
Object[] arr = de_que.toArray();
System.out.println("\nArray Size : " + arr.length);
System.out.print("Array elements : ");
for (int i = 0; i < arr.length; i++)
System.out.print(" " + arr[i]);
// peek() method : to get head
System.out.println("\nHead element : "
+ de_que.peek());
// poll() method : to get head
System.out.println("Head element poll : "
+ de_que.poll());
// push() method :
de_que.push(265);
de_que.push(984);
de_que.push(2365);
// remove() method : to get head
System.out.println("Head element remove : "
+ de_que.remove());
System.out.println("Final Array: " + de_que);
}
}
// Java program to demonstrate implementation// of ArrayDequeimport java.util.*;public class ArrayDequeExample { public static void main(String[] args) { // Initializing an deque Deque<Integer> de_que = new ArrayDeque<Integer>(10); // add() method to insert de_que.add(10); de_que.add(20); de_que.add(30); de_que.add(40); de_que.add(50); for (Integer element : de_que) { System.out.println("Element : " + element); } System.out.println("Using clear() "); // clear() method de_que.clear(); // addFirst() method to insert at start de_que.addFirst(564); de_que.addFirst(291); // addLast() method to insert at end de_que.addLast(24); de_que.addLast(14); System.out.println( "Above elements have been cleared"); // Iterator() : System.out.println( "Elements of deque using Iterator :"); for (Iterator itr = de_que.iterator(); itr.hasNext();) { System.out.println(itr.next()); } // descendingIterator() : to reverse the deque order System.out.println( "Print elements in reverse order :"); for (Iterator dItr = de_que.descendingIterator(); dItr.hasNext();) { System.out.println(dItr.next()); } // element() method : to get Head element System.out.println( "\nHead Element using element(): " + de_que.element()); // getFirst() method : to get Head element System.out.println( "Getting Head Element using getFirst(): " + de_que.getFirst()); // getLast() method : to get last element System.out.println( "Getting Last Element using getLast(): " + de_que.getLast()); // toArray() method : Object[] arr = de_que.toArray(); System.out.println("\nArray Size : " + arr.length); System.out.print("Array elements : "); for (int i = 0; i < arr.length; i++) System.out.print(" " + arr[i]); // peek() method : to get head System.out.println("\nHead element : " + de_que.peek()); // poll() method : to get head System.out.println("Head element poll : " + de_que.poll()); // push() method : de_que.push(265); de_que.push(984); de_que.push(2365); // remove() method : to get head System.out.println("Head element remove : " + de_que.remove()); System.out.println("Final Array: " + de_que); }}Output
Element : 10 Element : 20 Element : 30 Element : 40 Element : 50 Using clear() Above elements have been cleared Elements of deque using Iterator : 291 564 24 14 Print elements in reverse order : 14 24 564 291 Head Element using element(): 291 Getting Head Element using getFirst(): 291 Getting Last Element using getLast(): 14 Array Size : 4 Array elements : 291 564 24 14 Head element : 291 Head element poll : 291 Head element remove : 2365 Final Array: [984, 265, 564, 24, 14]
