BlockingDeque putLast() function in Java with Examples

The putLast(E e) method of BlockingDeque inserts the specified element into the queue represented by this deque (in other words, at the tail/end of this deque). If the Deque is capacity restricted, then it will wait for the space to become available.

Syntax:

public void putLast(E e)

Parameters: This method accepts a mandatory parameter e which is the element to be inserted at the end of the BlockingDeque.

Returns: This method does not return anything.

Exceptions: The program throws two exceptions as shown below:

• NullPointerException – if the specified element is null
• InterruptedException – if interrupted while waiting

Note: The putLast() method of BlockingDeque has been inherited from the LinkedBlockingDeque class in Java.

Below programs illustrate putLast() method of BlockingDeque:

Program 1:

// Java Program Demonstrate putLast()
// method of BlockingDeque

import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.BlockingDeque;
import java.util.*;

public class GFG {
    public static void main(String[] args)
        throws InterruptedException
    {

        // create object of BlockingDeque
        BlockingDeque<Integer> BD
            = new LinkedBlockingDeque<Integer>();

        // Add numbers to end of BlockingDeque
        BD.putLast(7855642);
        BD.putLast(35658786);
        BD.putLast(5278367);
        BD.putLast(74381793);

        // print Dequeue
        System.out.println("Blocking Deque: " + BD);
    }
}

Output:

Blocking Deque: [7855642, 35658786, 5278367, 74381793]

Program 2:

// Java Program Demonstrate putLast()
// method of BlockingDeque
// throwing NullPointerException

import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.BlockingDeque;
import java.util.*;

public class GFG {
    public static void main(String[] args)
        throws InterruptedException
    {

        // create object of BlockingDeque
        BlockingDeque<Integer> BD
            = new LinkedBlockingDeque<Integer>();

        // Add numbers to end of BlockingDeque
        BD.putLast(7855642);
        BD.putLast(35658786);
        BD.putLast(5278367);

        // throws an exception
        BD.putLast(null);

        // print Dequeue
        System.out.println("Blocking Deque: " + BD);
    }
}

Output:

Exception in thread "main" java.lang.NullPointerException
    at java.util.concurrent.LinkedBlockingDeque.putLast(LinkedBlockingDeque.java:390)
    at GFG.main(GFG.java:24)

Program 3:

// Java Program Demonstrate putLast()
// method of BlockingDeque
// when capacity exceeded

import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.BlockingDeque;
import java.util.*;

public class GFG {
    public static void main(String[] args)
        throws InterruptedException
    {

        // create object of BlockingDeque
        BlockingDeque<Integer> BD
            = new LinkedBlockingDeque<Integer>(3);

        // Add numbers to end of BlockingDeque
        BD.putLast(7855642);
        BD.putLast(35658786);
        BD.putLast(5278367);

        // throws an exception
        BD.putLast(4356789);

        // print Dequeue
        System.out.println("Blocking Deque: " + BD);
    }
}

Output:

Max real time limit exceeded due to either by heavy load on server or by using sleep function

Reference: https://docs.oracle.com/javase/7/docs/api/java/util/concurrent/BlockingDeque.html#putLast(E)