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()