The clear() method of PriorityBlockingQueue removes all the elements from this queue. Therefore this method can be applied when it is required to clear the PriorityBlockingQueue.
Syntax:
public void clear()
Parameter:
This method takes no parameters.
Returns:
This method returns nothing.
Exception:
This method does not throw any Exception.
Below program illustrate removing all the elements from PriorityBlockingQueue using clear() method.
Example 1:
// Java Program to Demonstrate clear() method// of PriorityBlockingQueue.  import java.util.concurrent.PriorityBlockingQueue;  public class GFG {      public static void main(String[] args)    {        // define capacity of PriorityBlockingQueue        int capacity = 15;          // create object of PriorityBlockingQueue        PriorityBlockingQueue<Integer> PrioBlockingQueue            = new PriorityBlockingQueue<Integer>(capacity);          // add numbers        PrioBlockingQueue.add(78758575);        PrioBlockingQueue.add(63447688);        PrioBlockingQueue.add(56434788);          // print queue after add operation        System.out.println("After Adding Numbers:");        System.out.println("PriorityBlockingQueue:"                           + PrioBlockingQueue);          // remove all the elements using clear() method        PrioBlockingQueue.clear();          // print queue after clear operation        System.out.println("\nAfter clear operation:");        System.out.println("PriorityBlockingQueue:"                           + PrioBlockingQueue);    }} |
Output:
After Adding Numbers: PriorityBlockingQueue:[56434788, 78758575, 63447688] After clear operation: PriorityBlockingQueue:[]
Example 2: To illustrate clear method on a PriorityBlockingQueue which contains a list of names.
// Java Program to Demonstrate clear() method// of PriorityBlockingQueue.  import java.util.concurrent.PriorityBlockingQueue;  public class GFG {      public static void main(String[] args)    {        // define capacity of PriorityBlockingQueue        int capacity = 15;          // create object of PriorityBlockingQueue        PriorityBlockingQueue<String> PrioBlockingQueue            = new PriorityBlockingQueue<String>(capacity);          // add some names        PrioBlockingQueue.add("Tandrima");        PrioBlockingQueue.add("Argha");        PrioBlockingQueue.add("Arka");          // print queue after add operation        System.out.println("List of Names:");        System.out.println("PriorityBlockingQueue: "                           + PrioBlockingQueue);          // remove all the elements using clear() method        PrioBlockingQueue.clear();          // print queue after clear operation        System.out.println("\nAfter clearing List of names:");        System.out.println("PriorityBlockingQueue:"                           + PrioBlockingQueue);    }} |
Output:
List of Names: PriorityBlockingQueue: [Argha, Tandrima, Arka] After clearing List of names: PriorityBlockingQueue:[]
Reference: https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/PriorityBlockingQueue.html#clear–
