Java PriorityQueue spliterator() Method

Description

The Java PriorityQueue spliterator() method creates a late-binding and fail-fast Spliterator for the elements in this queue. Late binding means the spliterator binds to the source of elements at the time of traversal and not when it is created. Spliterator is a better iterator and provides more controls over items during traversal.

Declaration

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

public Spliterator<E> spliterator()

Parameters

NA

Return Value

This method returns a Spliterator over the elements in this queue.

Exception

NA

Getting Spliterator() to iterate PriorityQueue of Ints Example

The following example shows the usage of Java PriorityQueue spliterator() method with Integers. We're creating an PriorityQueue of Integers, adding some elements, and then Spliterator is created using spliterator() method. The iterator is then used to traverse the items and to print them.

package com.tutorialspoint;

import java.util.PriorityQueue;
import java.util.Spliterator;

public class PriorityQueueDemo {
   public static void main(String[] args) {
      
      // create an empty priority queue
      PriorityQueue<Integer> queue = new PriorityQueue<>();

      // use add() method to add elements in the queue
      queue.add(25);
      queue.add(30);
      queue.add(20);
      queue.add(18);        

      // get the spliterator
      Spliterator<Integer> spliterator = queue.spliterator();

      // use the spliterator to print each item
      spliterator.forEachRemaining(i -> System.out.println(i));
   }
}

Output

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

18
20
25
30

Getting Spliterator() to iterate PriorityQueue of Strings Example

The following example shows the usage of Java PriorityQueue spliterator() method with Strings. We're creating an PriorityQueue of Strings, adding some elements, and then Spliterator is created using spliterator() method. The iterator is then used to traverse the items and to print them.

package com.tutorialspoint;

import java.util.PriorityQueue;
import java.util.Spliterator;

public class PriorityQueueDemo {
   public static void main(String[] args) {
      
      // create an empty priority queue
      PriorityQueue<String> queue = new PriorityQueue<>();

      // use add() method to add elements in the queue
      queue.add("A");
      queue.add("B");
      queue.add("C");
      queue.add("D");        

      // get the spliterator
      Spliterator<String> spliterator = queue.spliterator();

      // use the spliterator to print each item
      spliterator.forEachRemaining(i -> System.out.println(i));
   }
}

Output

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

A
B
C
D

Getting Spliterator() to iterate PriorityQueue of Objects Example

The following example shows the usage of Java PriorityQueue spliterator() method with Student objects. We're creating an PriorityQueue of Student objects, adding some elements, and then Spliterator is created using spliterator() method. The iterator is then used to traverse the items and to print them.

package com.tutorialspoint;

import java.util.PriorityQueue;
import java.util.Spliterator;

public class PriorityQueueDemo {
   public static void main(String[] args) {
      
      // create an empty priority queue
      PriorityQueue<Student> queue = new PriorityQueue<>();

      // use add() method to add elements in the queue
      queue.add(new Student(1, "Julie"));
      queue.add(new Student(2, "Robert"));
      queue.add(new Student(3, "Adam"));       

      // get the spliterator
      Spliterator<Student> spliterator = queue.spliterator();

      // use the spliterator to print each item
      spliterator.forEachRemaining(i -> System.out.println(i));
   }
}
class Student implements Comparable<Student> {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
   
   @Override
   public boolean equals(Object obj) {
      Student s = (Student)obj;
      return this.rollNo == s.rollNo && this.name.equalsIgnoreCase(s.name);
   }

   @Override
   public int compareTo(Student student) {
      return this.rollNo - student.rollNo;
   }
}

Output

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

[ 1, Julie ]
[ 2, Robert ]
[ 3, Adam ]