The java.util.concurrent.LinkedTransferQueue.peek() method is an in-built function in Java which is used to return the head of the queue if the queue is non-empty.
Syntax:
LinkedTransferQueue.peek()
Parameters: The function does not accept any parameter.
Return Value: The function returns the head of the queue if the queue is non-empty, otherwise it returns null.
Below programs illustrate the LinkedTransferQueue.peek() method:
Program 1:
// Java Program Demonstrate peek()// method of LinkedTransferQueue import java.util.concurrent.LinkedTransferQueue; class LinkedTransferQueuePeekExample1 { public static void main(String[] args) { // Initializing the queue LinkedTransferQueue<Character> queue = new LinkedTransferQueue<Character>(); // Adding elements to this queue for (char ch = 'A'; ch <= 'Z'; ch++) { queue.add(ch); } // Printing the head of the queue System.out.println("The head of the queue is " + queue.peek()); // Printing all the elements of the queue System.out.println("The elements in the queue :"); for (Character i : queue) System.out.print(i + " "); }} |
Output:
The head of the queue is A The elements in the queue : A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Program 2:
// Java Program Demonstrate peek()// method of LinkedTransferQueue import java.util.concurrent.LinkedTransferQueue; class LinkedTransferQueuePeekExample2 { public static void main(String[] args) { // Initializing the queue LinkedTransferQueue<Integer> queue = new LinkedTransferQueue<Integer>(); // Adding elements to this queue for (int i = 10; i <= 50; i += 10) queue.add(i); // Printing the head of the queue System.out.println("The head of the queue is " + queue.peek()); // Printing all the elements of the queue System.out.println("The elements in the queue :"); for (Integer i : queue) System.out.print(i + " "); }} |
Output:
The head of the queue is 10 The elements in the queue : 10 20 30 40 50
Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/LinkedTransferQueue.html#peek()