Java LinkedBlockingDeque clear() method

The clear() method of LinkedBlockingDeque class automatically withdraws all the elements from this deque. The deque becomes empty, after calling this method.

Syntax:

Parameters:

Specified By:

The clear() method of class LinkedBlockingDeque is specified by clear() method in interface Collection<E>.

Override:

The clear() method of class LinkedBlockingDeque overrides the clear() method of class AbstractQueue<E>.

Example 1

import java.util.concurrent.LinkedBlockingDeque;
public class LinkedBlockingDequeClearExample1 {
    public static void main(String[] args) {
        LinkedBlockingDeque<Integer> deque = new LinkedBlockingDeque<Integer>();
        deque.add(23);
        deque.add(123);
        deque.add(12);
        System.out.println("Deque : "+deque);
        System.out.println("After applying clear() method :  ");
        // clear() method will erase the whole deque
        deque.clear();
        System.out.println("Deque : "+deque);
    }
}

Test it Now

Output:

Deque : [23, 123, 12]
After applying clear() method :  
Deque : []

Example 2

import java.util.Scanner;
import java.util.concurrent.LinkedBlockingDeque;
class ShoppingList{
    int SNo;
    String Name;
    public ShoppingList(int SNo, String name) {
        this.SNo = SNo;
        Name = name;
    }
    public String toString(){
        return SNo+". "+ Name ;
    }
}
public class LinkedBlockingDequeClearExample2 {
    public static void main(String[] args) {
        LinkedBlockingDeque<ShoppingList> deque = new LinkedBlockingDeque<ShoppingList>();
        ShoppingList list1 = new ShoppingList(1,"Sugar");
        ShoppingList list2= new ShoppingList(2,"Salt");
        ShoppingList list3 = new ShoppingList(3,"Potato");
        ShoppingList list4 = new ShoppingList(4,"Rice");
        deque.add(list1);
        deque.add(list2);
        deque.add(list3);
        deque.add(list4);
        for (ShoppingList xyz : deque ){
            System.out.println(xyz);
        }
        Scanner scanner = new Scanner(System.in);
        System.out.println("Is Your shopping done.?");
        System.out.print("true/false : ");
        Boolean val = true;
        if(val.equals(true)){
            // clear() method will erase the whole deque
            deque.clear();
            System.out.println("Your queue is empty.\nMake a new list.");
        }
        else{
            System.out.println("Ok .You can add more items to your list");
        }
    }
}

Output:

1. Sugar
2. Salt
3. Potato
4. Rice
Is Your shopping done.?
true/false : Your queue is empty.
Make a new list.

Example 3

import java.util.concurrent.LinkedBlockingDeque;
public class LinkedBlockingDequeClearExample3 {
    public static void main(String[] args) {
        LinkedBlockingDeque<String> deque = new LinkedBlockingDeque<String>();
        deque.add(null);
        deque.add("bhavika");
        System.out.println("Name = "+deque);
        System.out.println("After clearing the queue :");
        // clear() method will erase the whole queue
        deque.clear();
        System.out.println("Name = "+deque);
    }
}

Test it Now

Output:

Exception in thread "main" java.lang.NullPointerException
	at java.util.concurrent.LinkedBlockingDeque.offerLast(LinkedBlockingDeque.java:357)
	at java.util.concurrent.LinkedBlockingDeque.addLast(LinkedBlockingDeque.java:334)
	at java.util.concurrent.LinkedBlockingDeque.add(LinkedBlockingDeque.java:633)
	at com.javaTpoint.LinkedBlockingDequeClearExample3.main(LinkedBlockingDequeClearExample3.java:7)

Next TopicJava Linkedblockingdeque

← prev next →