java.util.PriorityQueue.toArray() Method

Description

The toArray(T[] a) method is used to return an array containing all of the elements in this queue.

Declaration

Following is the declaration for java.util.PriorityQueue.toArray() method.

public <T> T[] toArray(T[] a)					 

Parameters

• a-- The array into which the elements of the queue are to be stored.

Return Value

• The method call returns an array containing all of the elements in this queue.

Exception

• ArrayStoreException--Throws if the runtime type of the specified array is not a supertype of the runtime type of every element in this queue.

• NullPointerException--Throws if the specified array is null.

Example

The following example shows the usage of java.util.PriorityQueue.toArray()

package com.tutorialspoint;

import java.util.*;

public class PriorityQueueDemo {
   public static void main(String args[]) {
      // create priority queue
      PriorityQueue < Integer >  prq = new PriorityQueue < Integer > (); 
       
      // insert values in the queue
      prq.add(6);  
      prq.add(9);
      prq.add(5);
      prq.add(64);
      prq.add(6);
      
      System.out.println ( "Priority queue values are: "+ prq);
      
      // create arr1
      Integer[] arr1 = new Integer[5];
      
      // use toArrsy() method
      Integer[] arr2 = prq.toArray(arr1); 
  
      System.out.println ( "Value in arr1: ");
      
      for ( int i = 0; i<arr1.length; i++ ){  
         System.out.println ( "Value: " + arr1[i]) ; 
      }
      
      System.out.println ( "Value in arr2: ");
      
      for ( int i = 0; i<arr2.length; i++ ){  
         System.out.println ( "Value: " + arr2[i]) ; 
      }
   }
}

Let us compile and run the above program, this will produce the following result.

Priority queue values are: [5, 6, 6, 64, 9]
Value in arr1: 
Value: 5
Value: 6
Value: 6
Value: 64
Value: 9
Value in arr2: 
Value: 5
Value: 6
Value: 6
Value: 64
Value: 9