July 2011 – Software development and other things

Recently I played with BitSets in Java because I needed an efficient way to store huge amounts of long values. For Java there is the java.util.BitSet class. It is a very efficient implementation when you only need to store bit values. Here is a trivial example on how to use it:

import java.util.BitSet;

public class BitSetTest {
    
    public static void main(String args[]) {
        
        BitSet primeBits = new BitSet();
        primeBits.set(2);
        primeBits.set(3);
        primeBits.set(5);
        primeBits.set(7);
        primeBits.set(11);
        
        BitSet evenBits = new BitSet();
        evenBits.set(0);
        evenBits.set(2);
        evenBits.set(4);
        evenBits.set(6);
        evenBits.set(8);
        evenBits.set(10);
        
        //primeBits.and(evenBits);  // will result in primeBits only containing 2
        primeBits.andNot(evenBits);
        
        System.out.println(primeBits); // {3, 5, 7, 11}
        
    }
}

import java.util.BitSet;

public class BitSetTest {

public static void main(String args[]) {

BitSet primeBits = new BitSet();

primeBits.set(2);

primeBits.set(3);

primeBits.set(5);

primeBits.set(7);

primeBits.set(11);

BitSet evenBits = new BitSet();

evenBits.set(0);

evenBits.set(2);

evenBits.set(4);

evenBits.set(6);

evenBits.set(8);

evenBits.set(10);

//primeBits.and(evenBits); // will result in primeBits only containing 2

primeBits.andNot(evenBits);

System.out.println(primeBits); // {3, 5, 7, 11}

}

It is very […]

Month: July 2011

How to use java.util.concurrent.CountDownLatch

BitSets in Scala are much more fun than in Java