19. RandomAccessFile example: fixed-length string I/O

• 
  import java.io.*;
  // Utility class for reading/writing Strings of fixed length padded with zeroes
  public class IOStringUtils
  {
      // out parameter is a RandomAccessFile object
      // length is the size of the fixed length string to be written
      public static void writeFixedString(
      DataOutput out, int length, String s)
      throws IOException
      {
          for (int i = 0; i < length; i++)
          {
              if (i < s.length())
                  out.writeChar(s.charAt(i)); // write char
              else
                  out.writeChar(0);   // write Unicode zero
          }
      }
  
      // in parameter is a RandomAccessFile object
      public static String readFixedString(
      DataInput in, int length) throws IOException
      {
          StringBuilder sb = new StringBuilder();
          for (int i = 0; i < length; i++)
          {
              char c = in.readChar();
              // if char is not Unicode zero add to string
              if (c != 0)
                  sb.append(c);
          }
          return sb.toString();
      }
  }//class IOStringUtils