El método java.util.concurrent.ConcurrentLinkedDeque.offerFirst() es un método incorporado en Java que inserta el elemento especificado, pasado como parámetro, al frente de la deque.
Sintaxis:
Conn_Linked_Deque.offerFirst(Object elem)
Parámetros: el método acepta un parámetro elem que especifica el elemento que se insertará al frente del deque.
Valor devuelto: la función devuelve True si el elemento se agrega con éxito a la deque y devuelve False en caso contrario.
Excepción: la función lanza una NullPointerException si el parámetro pasado es NULL .
Los siguientes programas ilustran el método ConcurrentLinkedDeque.offerFirst():
Programa 1 :
/* Java Program to Demonstrate offerFirst()
method of ConcurrentLinkedDeque */
import java.util.concurrent.*;
class GFG {
public static void main(String[] args)
{
// Creating an empty Deque
ConcurrentLinkedDeque<String> cld =
new ConcurrentLinkedDeque<String>();
// Add elements into the Deque
cld.add("Welcome");
cld.add("To");
cld.add("Geeks");
cld.add("4");
cld.add("Geeks");
// Displaying the Deque
System.out.println("Elements in Deque: "
+ cld);
// Displaying the First element
System.out.println("The First element is: " +
cld.getFirst());
/* Insert an element at the front
of the deque */
if (cld.offerFirst("GFG")) {
// Displaying the First element
System.out.println("The Inserted element is: " +
cld.getFirst());
}
// Displaying the Deque
System.out.println("Elements in Deque: "
+ cld);
// Displaying the First element
System.out.println("The First element is: " +
cld.getFirst());
}
}
Elements in Deque: [Welcome, To, Geeks, 4, Geeks] The First element is: Welcome The Inserted element is: GFG Elements in Deque: [GFG, Welcome, To, Geeks, 4, Geeks] The First element is: GFG
Programa 2:
/* Java Program to Demonstrate offerFirst()
method of ConcurrentLinkedDeque */
import java.util.concurrent.*;
class GFG {
public static void main(String[] args)
{
// Creating an empty Deque
ConcurrentLinkedDeque<Integer> cld =
new ConcurrentLinkedDeque<Integer>();
// Add elements into the Deque
cld.add(12);
cld.add(43);
cld.add(29);
cld.add(16);
cld.add(70);
// Displaying the Deque
System.out.println("Elements in Deque: "
+ cld);
// Displaying the First element
System.out.println("The First element is: " +
cld.getFirst());
try {
cld.offerFirst(null);
}
catch (Exception e) {
System.out.println(e);
}
/* Insert an element at the front
of the deque */
if (cld.offerFirst(74)) {
// Displaying the First element
System.out.println("The Inserted element is: " +
cld.getFirst());
}
// Displaying the Deque
System.out.println("Elements in Deque: "
+ cld);
// Displaying the First element
System.out.println("The First element is: " +
cld.getFirst());
}
}
Elements in Deque: [12, 43, 29, 16, 70] The First element is: 12 java.lang.NullPointerException The Inserted element is: 74 Elements in Deque: [74, 12, 43, 29, 16, 70] The First element is: 74
Referencia: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentLinkedDeque.html#offerFirst()
Publicación traducida automáticamente
Artículo escrito por RICHIK BHATTACHARJEE y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA