Java ConcurrentLinkedQueue contains() Method

The contains() method of ConcurrentLinkedQueue class returns a Boolean value true if the specified element is present in this queue.

Syntax:

Parameters:

o - this is the object that is to be checked for the presence in this queue.

Specified By:

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

Override:

The contains() method of class ConcurrentLinkedQueue is overridden by :

contains() method in class AbstractCollection<E>.

Return Value:

The contains() method returns the Boolean value true if the specified element is present in this queue else it returns false.

Example 1

import java.util.Iterator;
import java.util.concurrent.ConcurrentLinkedQueue;
public class ConcurrentLinkedQueueContainsExample1 {
    static int i=1;
    public static void main(String[] args) {
        ConcurrentLinkedQueue<String> queue = new ConcurrentLinkedQueue<String>();
        queue.add("Ram");
        queue.add("Sham");
        queue.add("Mira");
        queue.add("Rajesh");
        Iterator<String> iterator = queue.iterator();
        //Returns an iterator over the elements
        while(iterator.hasNext()){
            System.out.println(i++ +"."+iterator.next());
        }
         /*contains() method will return a boolean value if the
          specified object is present in the queue*/
        if(queue.contains("Ram")) {
            System.out.println("Ram is present");
        }
        else{
            System.out.println("Ram is absent");
        }
    }
}

Test it Now

Output:

1.Ram
2.Sham
3.Mira
4.Rajesh
Ram is present

Example 2

import java.util.Scanner;
import java.util.concurrent.ConcurrentLinkedQueue;
public class ConcurrentLinkedQueueContainsExample2 {
    public static void main(String[] args) {
        
        ConcurrentLinkedQueue<Integer> queue = new     	ConcurrentLinkedQueue<Integer>();
        queue.add(3);
        queue.add(5);
        queue.add(7);
        queue.add(2);
        int a=4;
        if(queue.contains(a)) {
            System.out.println("Your answer is correct.");
        }
        else{
        System.out.println("Incorrect answer!");
        }
    }
}

Output:

Incorrect answer!

Example 3

import java.util.Scanner;
import java.util.concurrent.ConcurrentLinkedQueue;
class Employee{
    public static String name;
    static  String date;
    public Employee(String name, String date) {
        this.name = name;
        this.date = date;
    }
}
public class ConcurrentLinkedQueueContainsExample3 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
    ConcurrentLinkedQueue<Employee> queue = new ConcurrentLinkedQueue<Employee>();
        Employee employee1=new Employee("Ravi","12.08.18");
        Employee employee2=new Employee("Simran","12.08.18");
        Employee employee3=new Employee("Raj","12.08.18");
        Employee employee4=new Employee("Rajiv","12.08.18");
        queue.add(employee1);
        queue.add(employee2);
        queue.add(employee3);
        queue.add(employee4);
        if (queue.contains(employee2)){
            System.out.println("Simran is present on "+Employee.date);
        }
        else{
            System.out.println("Simran is absent on "+Employee.date);
        }
    }
}

Output: