Java.util.ArrayDeque Class in Java | Set 2
Last Updated :
02 Nov, 2022
Java.util.ArrayDeque Class in Java | Set 1
More Methods of util.ArrayDeque Class :
16. offer(Element e) : java.util.ArrayDeque.offer(Element e) : inserts element at the end of deque.
Syntax :
public boolean offer(Element e)
Parameters :
e - element to add
Return :
true, if element is added else; false
17. offerFirst(Element e) : java.util.ArrayDeque.offerFirst(Element e) : inserts element at the front of deque.
Syntax :
public boolean offerFirst(Element e)
Parameters :
e - element to add
Return :
true, if element is added else; false
18. offerLast(Element e) : java.util.ArrayDeque.offerLast(Element e) : inserts element at the end of deque.
Syntax :
public boolean offerLast(Element e)
Parameters :
e - element to add
Return :
true, if element is added else; false
19. peek() : java.util.ArrayDeque.peek(): returns head element without removing it.
Syntax :
public E peek()
Parameters :
--------
Return :
head of deque or null if deque is empty.
20. peekFirst() : java.util.ArrayDeque.peekFirst() :returns first element without removing it.
Syntax :
public E peekFirst()
Parameters :
--------
Return :
first element of deque or null if deque is empty.
21. peekLast() : java.util.ArrayDeque.peek(): returns last element without removing it.
Syntax :
public E peekLast()
Parameters :
--------
Return :
Last element of deque or null if deque is empty.
22. poll() : java.util.ArrayDeque.peek(): returns head element and also removes it
Syntax :
public E poll()
Parameters :
--------
Return :
head of deque or null if deque is empty.
23. pollFirst() : java.util.ArrayDeque.peek(): returns first element and also removes it
Syntax :
public E pollFirst()
Parameters :
--------
Return :
first element of deque or null if deque is empty.
24. pollLast() : java.util.ArrayDeque.peek(): returns last element and also removes it
Syntax :
public E pollLast()
Parameters :
--------
Return :
last element of deque or null if deque is empty.
25. pop() : java.util.ArrayDeque.pop() : pops out an element for stack represented by deque
Syntax :
public E pop()
Parameters :
---------
Return :
element at front
26. push(Element e) : java.util.ArrayDeque.push(Element e) : pushes an element onto stack represented by deque
Syntax :
public void push(Element e)
Parameters :
e : element to be pushed
Return :
----------
27. remove() : java.util.ArrayDeque.remove(): returns head element and also removes it
Syntax :
public E remove()
Parameters :
------
Return :
head of the deque
28. removeFirst() : java.util.ArrayDeque.remove(): returns first element and also removes it
Syntax :
public E removeFirst()
Parameters :
------
Return :
first element of the deque
29. removeLast() : java.util.ArrayDeque.remove(): returns last element and also removes it
Syntax :
public E removeLast()
Parameters :
------
Return :
last element of the deque
30. removeFirstOccurrence(Obj) : java.util.ArrayDeque.removeFirstOccurrence(Obj) : removes the element where it first occur in the deque.
Syntax :
public boolean removeFirstOccurrence(Object obj)
Parameters :
obj : element to be removed
Return :
true, if the element is removed; else False
31. removeLastOccurrence(Obj) : java.util.ArrayDeque.removeLastOccurrence(Obj) : removes the element where it last occur in the deque.
Syntax :
public boolean removeLastOccurrence(Object obj)
Parameters :
obj : element to be removed
Return :
true, if the element is removed; else False
Java Program explaining util.ArrayDeque class methods :
Java
// Java code explaining the use of ArrayDeque class methods
// offer(), offerFirst(), offerLast(), peek(), peekFirst(), peekLast()
// poll(), peekFirst(), peekLast(), pop(), push()
import java.util.*;
public class NewClass
{
public static void main(String[] args)
{
// Initializing an deque
Deque<Integer> d = new ArrayDeque<Integer>(10);
// add() method to insert
d.add(2);
d.add(4);
// offer() : add element at end
d.offer(100);
d.offer(101);
// offerFirst() : add element at start
d.offerFirst(1111);
d.offerFirst(3333);
// offerLast() : add element at end
d.offerLast(5000);
d.offerLast(50001);
for (Integer element : d)
{
System.out.println("Element : " + element);
}
// peek() method : to get head
System.out.println("\nHead element : " + d.peek());
// peekFirst() method : to get First element
System.out.println("First element : " + d.peekFirst());
// peekLast() method : to get Last element
System.out.println("Last element : " + d.peekLast());
// poll() method : to get head
System.out.println("\nHead element poll : " + d.poll());
// pollFirst() method : to get First element
System.out.println("First element poll : " + d.pollFirst());
// pollLast() method : to get Last element
System.out.println("Last element poll : " + d.pollLast() + "\n");
for (Integer element : d)
{
System.out.println("Element : " + element);
}
// pop() method :
System.out.println("Pop element : " + d.pop());
// push() method :
d.push(11010101);
d.push(121212121);
d.push(131313131);
// remove() method : to get head
System.out.println("\nHead element remove : " + d.remove());
// removeFirst() method : to get First element
System.out.println("First element remove : " + d.removeFirst());
// removeLast() method : to get Last element
System.out.println("Last element remove : " + d.removeLast() + "\n");
for (Integer element : d)
{
System.out.println("Element : " + element);
}
}
}
Output :
Element : 3333
Element : 1111
Element : 2
Element : 4
Element : 100
Element : 101
Element : 5000
Element : 50001
Head element : 3333
First element : 3333
Last element : 50001
Head element poll : 3333
First element poll : 1111
Last element poll : 50001
Element : 2
Element : 4
Element : 100
Element : 101
Element : 5000
Pop element : 2
Head element remove : 131313131
First element remove : 121212121
Last element remove : 5000
Element : 11010101
Element : 4
Element : 100
Element : 101
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