The java.util.concurrent.ConcurrentLinkedDeque.offer() method is an inbuilt method in Java which inserts the specified element, passed as a parameter, to the deque.
Syntax:
public boolean offer(E elem)
Parameters: The method accepts a parameter elem which species the element to be inserted to the deque.
Return Value: The function returns True if the element is successfully added into the deque and returns False otherwise.
Exception: The function throws a NullPointerException if the passed parameter is NULL.
Below programs illustrate the ConcurrentLinkedDeque.offer() method:
Program 1:
// Java Program to Demonstrate offer() // 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( "ConcurrentLinkedDeque: "
+ cld);
// Insert an element using offer()
if (cld.offer( "GFG" )) {
// Displaying message
System.out.println( "Element Inserted" );
}
else {
// Displaying message
System.out.println( "Element not Inserted" );
}
// Displaying the Deque
System.out.println( "ConcurrentLinkedDeque: "
+ cld);
}
} |
ConcurrentLinkedDeque: [Welcome, To, Geeks, 4, Geeks] Element Inserted ConcurrentLinkedDeque: [Welcome, To, Geeks, 4, Geeks, GFG]
// Java Program to Demonstrate offer() // 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( "ConcurrentLinkedDeque: "
+ cld);
try {
// Insert null element using offer()
cld.offer( null );
}
catch (Exception e) {
System.out.println(e);
}
}
} |
ConcurrentLinkedDeque: [Welcome, To, Geeks, 4, Geeks] java.lang.NullPointerException
Reference: https://docs.oracle.com/javase/9/docs/api/java/util/concurrent/ConcurrentLinkedDeque.html#offer-E-