Re: Reading from a Random Access File

Here's yet another.

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.util.Random;

/**
 * Alternating Byte Format
 *
 * Each (two byte) record consists
 * of two (one byte) fields.
 *
 * Field 1 RoomNumber.
 * Field 2 ComputerCount.
 *
 * Each field will represent an
 * integer value between 0-255.
 *
 */
public class RandomAccess
{
  public static void main(String[] args)
  {

    writeData();
    readData();
  }

  static void writeData()
  {
    File f = new File("Class Room Details.abf");
    Random rnd = new Random();
    byte[] fileContents = new byte[100];
    rnd.nextBytes(fileContents);
    try
    {
      FileOutputStream fos = new FileOutputStream(f);
      fos.write(fileContents);
      fos.close();
    }
    catch (FileNotFoundException e)
    {
      e.printStackTrace();
    }
    catch (IOException e)
    {
      e.printStackTrace();
    }
  }

  static void readData()
  {
    int roomNumber;
    int computerCount;
    try
    {
      File f = new File("Class Room Details.abf");
      RandomAccessFile raf = new RandomAccessFile(f, "r");
      while (raf.getFilePointer() < raf.length())
      {
        roomNumber = raf.readByte() & 0xFF;
        computerCount = raf.readByte() & 0xFF;
        shutdownComputers(roomNumber, computerCount);
      }
      raf.close();
    }
    catch (IOException e)
    {
      e.printStackTrace();
    }
  }

  static void shutdownComputers(int room, int count)
  {
    System.out.println("Shutdown " + count +
        " computers in Room " + room + ".\tBye");
  }
}