Collections.asLifoQueue in Java
February 02, 2022
Collections.asLifoQueue method.
static <T> Queue<T> asLifoQueue(Deque<T> deque)
asLifoQueue method returns a Last-in-first-out (Lifo) Queue for the specified Deque. The Deque allows element insertion and removal at both ends.
2. The
asLifoQueue is useful to create a Lifo Queue when required.
3. The
asLifoQueue accepts a Deque and returns a Queue instance.
Example-1
CollectionsAsLifoQueue1.java
package com.concretepage;
import java.util.ArrayDeque;
import java.util.Collections;
import java.util.Deque;
import java.util.Queue;
public class CollectionsAsLifoQueue1 {
public static void main(String[] args) {
Deque<String> arrayDeque = new ArrayDeque<>();
arrayDeque.add("A");
arrayDeque.add("B");
arrayDeque.add("C");
Queue<String> queue = Collections.asLifoQueue(arrayDeque);
queue.add("D");
System.out.println(queue);
System.out.println("queue.poll(): " + queue.poll());
}
}
[D, A, B, C] queue.poll(): D
Example-2
CollectionsAsLifoQueue2.java
package com.concretepage;
import java.util.ArrayDeque;
import java.util.Collections;
import java.util.Deque;
import java.util.Queue;
public class CollectionsAsLifoQueue2 {
public static void main(String[] args) {
Deque<Integer> arrayDeque = new ArrayDeque<>();
arrayDeque.add(10);
arrayDeque.add(20);
arrayDeque.add(30);
Queue<Integer> queue = Collections.asLifoQueue(arrayDeque);
queue.add(40);
System.out.println(queue);
System.out.println("queue.poll(): " + queue.poll());
}
}
[40, 10, 20, 30] queue.poll(): 40
