Describe the concept of Spliterators in Java. Enumerate the key methods provided by the Spliterator interface. Illustrate the usage of Spliterators with a suitable example.
Answer:-
Spliterator in Java
A Spliterator (split + iterator) is an advanced iterator introduced in Java 8. It is used to traverse and partition elements of a collection (like ArrayList, HashSet, etc.) for parallel and sequential processing.
Key Features of Spliterator
- Can split the collection into multiple parts for parallel processing.
- Works with Stream API.
- Supports both sequential and parallel traversal.
- Found in the
java.utilpackage.
Key Methods of Spliterator Interface
| Method | Description |
|---|---|
tryAdvance(Consumer<? super T> action) | Processes one element at a time |
forEachRemaining(Consumer<? super T> action) | Processes remaining elements in bulk |
trySplit() | Splits the iterator into two parts |
estimateSize() | Returns estimated number of elements |
characteristics() | Returns bitwise OR of Spliterator’s characteristics (e.g., ORDERED, SORTED, etc.) |
Common Characteristics Flags
Spliterator.ORDEREDSpliterator.SIZEDSpliterator.SORTEDSpliterator.NONNULLSpliterator.IMMUTABLESpliterator.CONCURRENT
Example Program: Using Spliterator
import java.util.*;
import java.util.function.Consumer;
public class SpliteratorDemo {
public static void main(String[] args) {
List<String> names = Arrays.asList("Kushal", "Aman", "Zara", "Neha", "Ravi");
// Get Spliterator
Spliterator<String> split1 = names.spliterator();
// Try splitting
Spliterator<String> split2 = split1.trySplit();
// First half
System.out.println("First Spliterator:");
split1.forEachRemaining(System.out::println);
// Second half
System.out.println("\nSecond Spliterator:");
if (split2 != null) {
split2.forEachRemaining(System.out::println);
}
// Size estimation
System.out.println("\nEstimated size: " + names.spliterator().estimateSize());
}
}
Output
First Spliterator: Kushal Aman Second Spliterator: Zara Neha Ravi Estimated size: 5
Summary
- Spliterator is useful for efficient traversal and partitioning, especially in parallel streams.
- It improves performance with large datasets using fork/join strategies.
