Close

Java - Spliterator Examples

Java 

Using Spliterator#getComparator() to get underlying source Comparator instance. This method will return null if no Comparator has been set. It will throw IllegalStateException if the source does not have SORTED characteristics. 

package com.logicbig.example;

import java.util.SortedSet;
import java.util.Spliterator;
import java.util.TreeSet;

public class SpliteratorComparatorExample {
    public static void main (String[] args) {
        SortedSet<Test> set =
                            new TreeSet<>((o1, o2) ->
                                                o1.str.compareTo(o2.str));

        set.add(new Test("two"));
        set.add(new Test("one"));
        Spliterator<Test> s = set.spliterator();
        System.out.println(s.getComparator());
        System.out.println(set);
    }

    private static class Test {
        private final String str;

        private Test (String str) {
            this.str = str;
        }

        @Override
        public String toString () {
            return "Test{str='" + str + "'}";
        }
    }
}

Output

com.logicbig.example.SpliteratorComparatorExample$$Lambda$1/1585509557@7b90559e
[Test{str='one'}, Test{str='two'}]
Original Post




Using Spliterator#estimateSize() and Spliterator#getExactSizeIfKnown(). These methods return the size of the remaining elements to traverse. 

package com.logicbig.example;

import java.util.Arrays;
import java.util.List;
import java.util.Spliterator;

public class SpliteratorSizeExample {

    public static void main (String[] args) {
        List<String> list = Arrays.asList("Apple", "Banana", "Orange");
        Spliterator<String> s = list.spliterator();
        s.tryAdvance(System.out::println);
        System.out.println(s.estimateSize());
        System.out.println(s.getExactSizeIfKnown());
    }
}

Output

Apple
2
2
Original Post




Using Spliterators to create a Spliterator instance for an array. 

package com.logicbig.example;

import java.util.Spliterator;
import java.util.Spliterators;

public class SpliteratorsExample {

    public static void main (String[] args) {
        Spliterator<String> s = Spliterators.spliterator(
                            new String[]{"one", "two"}, 0);
        s.forEachRemaining(System.out::println);
    }
}

Output

one
two
Original Post




Using Spliterator for primitive arrays. 

package com.logicbig.example;

import java.util.Arrays;
import java.util.Spliterator;
import java.util.function.IntConsumer;

public class SpliteratorPrimitiveExample {
    public static void main (String[] args) {
        int[] ints = {3, 4, 6, 7};
        Spliterator.OfInt s = Arrays.spliterator(ints);
        s.forEachRemaining((IntConsumer) System.out::println);
    }
}

Output

3
4
6
7
Original Post

Using Spliterator#trySplit() to partition the spliterator. It's used for parallel processing, specifically by Fork/Join framework. 

package com.logicbig.example;

import java.util.Arrays;
import java.util.List;
import java.util.Spliterator;

public class SpliteratorTrySplitExample {
    public static void main (String[] args) {
        List<String> list = Arrays.asList("Apple", "Banana", "Orange");

        Spliterator<String> s = list.spliterator();
        Spliterator<String> s1 = s.trySplit();

        s.forEachRemaining(System.out::println);
        System.out.println("-- traversing the other half of the spliterator --- ");
        s1.forEachRemaining(System.out::println);
    }
}

Output

Banana
Orange
-- traversing the other half of the spliterator --- 
Apple
Original Post




Querying all characteristics of this Spliterator. 

package com.logicbig.example;

import java.util.ArrayList;
import java.util.List;
import java.util.Spliterator;

public class SpliteratorCharacteristics {
    public static void main (String[] args) {
        List<String> list = new ArrayList<>();

        Spliterator<String> s = list.spliterator();

        if (s.hasCharacteristics(Spliterator.ORDERED)) {
            System.out.println("ORDERED");
        }
        if (s.hasCharacteristics(Spliterator.DISTINCT)) {
            System.out.println("DISTINCT");
        }
        if (s.hasCharacteristics(Spliterator.SORTED)) {
            System.out.println("SORTED");
        }
        if (s.hasCharacteristics(Spliterator.SIZED)) {
            System.out.println("SIZED");
        }

        if (s.hasCharacteristics(Spliterator.CONCURRENT)) {
            System.out.println("CONCURRENT");
        }
        if (s.hasCharacteristics(Spliterator.IMMUTABLE)) {
            System.out.println("IMMUTABLE");
        }
        if (s.hasCharacteristics(Spliterator.NONNULL)) {
            System.out.println("NONNULL");
        }
        if (s.hasCharacteristics(Spliterator.SUBSIZED)) {
            System.out.println("SUBSIZED");
        }
    }
}

Output

ORDERED
SIZED
SUBSIZED
Original Post




Finding spliterator characteristic and printing elements of the List 

package com.logicbig.example;

import java.util.Arrays;
import java.util.List;

public class SpliteratorExample {
    public static void main (String[] args) {
        List<String> list = Arrays.asList("Apple", "Banana", "Orange");

        System.out.println(list.spliterator().characteristics());
        for (String s : list) {
            System.out.println(s);
        }
    }
}

Output

16464
Apple
Banana
Orange
Original Post

Using Spliterator#tryAdvance() and Spliterator#forEachRemaining() to traverse the elements. With tryAdvance() method, we traverse elements individually one by one, whereas, forEachRemaining() gives us remaining elements in bulk. 

package com.logicbig.example;

import java.util.Arrays;
import java.util.List;
import java.util.Spliterator;

public class SpliteratorTryAdvanceExample {
    public static void main (String[] args) {
        List<String> list = Arrays.asList("Apple", "Banana", "Orange");

        Spliterator<String> s = list.spliterator();
        s.tryAdvance(System.out::println);
        System.out.println(" --- bulk traversal");
        s.forEachRemaining(System.out::println);

        System.out.println(" --- attempting tryAdvance again");
        boolean b = s.tryAdvance(System.out::println);
        System.out.println("Element exists: " + b);

    }
}

Output

Apple
 --- bulk traversal
Banana
Orange
 --- attempting tryAdvance again
Element exists: false
Original Post

See Also