MainClass.java Source code

Introduction

Here is the source code for MainClass.java

Source

import java.io.File;
import java.io.RandomAccessFile;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;

public class MainClass {
    public static void main(String[] args) throws Exception {
        File aFile = new File("C:/test.bin");
        RandomAccessFile ioFile = new RandomAccessFile(aFile, " rw");

        FileChannel ioChannel = ioFile.getChannel();
        final int PRIMESREQUIRED = 10;
        long[] primes = new long[PRIMESREQUIRED];

        int index = 0;
        final long REPLACEMENT = 999999L;

        final int PRIMECOUNT = (int) ioChannel.size() / 8;
        MappedByteBuffer buf = ioChannel.map(FileChannel.MapMode.READ_WRITE, 0L, ioChannel.size()).load();
        ioChannel.close();

        for (int i = 0; i < PRIMESREQUIRED; i++) {
            index = 8 * (int) (PRIMECOUNT * Math.random());
            primes[i] = buf.getLong(index);
            buf.putLong(index, REPLACEMENT);
        }

        for (long prime : primes) {
            System.out.printf("%12d", prime);
        }
        ioFile.close();
    }
}