El método peek() de ConcurrentLinkedQueue se usa para devolver el encabezado de ConcurrentLinkedQueue. Recupera, pero no elimina, el encabezado de esta ConcurrentLinkedQueue. Si ConcurrentLinkedQueue está vacío, este método devuelve un valor nulo.
Sintaxis:
public E peek()
Devoluciones: este método devuelve el encabezado de esta ConcurrentLinkedQueue sin eliminarlo.
Los siguientes programas ilustran el método peek() de ConcurrentLinkedQueue:
Ejemplo 1:
// Java Program Demonstrate peek()
// method of ConcurrentLinkedQueue
import java.util.concurrent.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<Integer>
queue = new ConcurrentLinkedQueue<Integer>();
// Add Numbers to queue
queue.add(4353);
queue.add(7824);
queue.add(78249);
queue.add(8724);
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
// find peek
int response1 = queue.peek();
// print after applying peek method
System.out.println("Head: " + response1);
// Verifying that the head is not removed
System.out.println("ConcurrentLinkedQueue after peek: " + queue);
}
}
Producción:
ConcurrentLinkedQueue: [4353, 7824, 78249, 8724] Head: 4353 ConcurrentLinkedQueue after peek: [4353, 7824, 78249, 8724]
Ejemplo 2:
// Java Program Demonstrate peek()
// method of ConcurrentLinkedQueue
import java.util.concurrent.*;
public class GFG {
public static void main(String[] args)
{
// create an ConcurrentLinkedQueue
ConcurrentLinkedQueue<String>
queue = new ConcurrentLinkedQueue<String>();
// Add String to queue
queue.add("Aman");
queue.add("Amar");
queue.add("Sanjeet");
queue.add("Rabi");
// Displaying the existing ConcurrentLinkedQueue
System.out.println("ConcurrentLinkedQueue: " + queue);
// find peek of queue
String response1 = queue.peek();
// print after applying peek method
System.out.println("Head: " + response1);
// Verifying that the head is not removed
System.out.println("ConcurrentLinkedQueue after peek: " + queue);
// remove some elements
queue.poll();
queue.poll();
// Displaying the existing ConcurrentLinkedQueue
System.out.println("Updated ConcurrentLinkedQueue: " + queue);
// find peek of queue
String response2 = queue.peek();
// print after applying peek method
System.out.println("Head: " + response1);
// Verifying that the head is not removed
System.out.println("ConcurrentLinkedQueue after peek: " + queue);
}
}
Producción:
ConcurrentLinkedQueue: [Aman, Amar, Sanjeet, Rabi] Head: Aman ConcurrentLinkedQueue after peek: [Aman, Amar, Sanjeet, Rabi] Updated ConcurrentLinkedQueue: [Sanjeet, Rabi] Head: Aman ConcurrentLinkedQueue after peek: [Sanjeet, Rabi]
Referencia: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentLinkedQueue.html#peek–
Publicación traducida automáticamente
Artículo escrito por AmanSingh2210 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA