import java.lancs.Person;

import java.util.Vector;
import java.util.Enumeration;

import java.io.File;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.DataOutputStream;
import java.io.FileOutputStream;

class PersistentPeople
{
  //
  // This function writes a collection of people to a file.  The
  // collection of people is specified by the Vector object, and the
  // name of the file to which the collection is written to is
  // specified by <filename>.
  //
  public static void writePeopleToFile (Vector people, 
                                        String filename) throws Exception
    {
      // Create the file
      File file = new File (filename);

      // Create the file stream
      FileOutputStream fileReader = new FileOutputStream (file);	

      // Create the output stream
      DataOutputStream outputStream = new DataOutputStream (fileReader);

      // Get the elements of the vector
      Enumeration iterator = people.elements ();
      
      // Go through the elements
      while (iterator.hasMoreElements ())
        {
          // Get to a person
          Person person = (Person) iterator.nextElement ();
          
          // Write the Forename (on a line)
          outputStream.writeBytes (person.getForename () + "\n");

          // Write the Surname (on a line)
          outputStream.writeBytes (person.getSurname () + "\n");

          // Write the Age (on a line)
          String ageString = new Integer (person.getAge ()).toString ();
          outputStream.writeBytes (ageString + "\n");

          // Write the Gender (on a line)
          String genderString = new Integer (person.getGender ()).toString ();
          outputStream.writeBytes (genderString + "\n");
        }
    }
          
  //
  // This function reads a collection of people from a file.  The
  // collection of people is return by the Vector object that is
  // returned, and the name of the file from which the collection is
  // read is specified by <filename>.
  //
  public static Vector readPeopleFromFile (String filename) throws Exception
    {
      // Create the file
      File file = new File (filename);

      // Create the file stream
      FileInputStream fileReader = new FileInputStream (file);	

      // Create the input stream
      DataInputStream inputStream = new DataInputStream (fileReader);

      // Create an (empty) collection
      Vector people = new Vector ();

      while (true)
        {
          // Read the Forename
          String forename = inputStream.readLine ();          

          // Make sure we haven't reach the end of the file
          if (forename == null)
            {
              break;
            }
          
          // Read the Surname
          String surname = inputStream.readLine ();          

          // Read the Age
          String ageString = inputStream.readLine ();          
          int age = Integer.parseInt (ageString);
          
          // Read the Gender
          String genderString = inputStream.readLine ();          
          int gender = Integer.parseInt (genderString);
          
          // Create the person
          Person person = new Person (forename, 
                                      surname,
                                      age, 
                                      gender);
          
          // Add the new person to the collection
          people.addElement (person);
        }
      
      // Return the collection
      return people;
    }
}


public class PersistentPeopleTester
{
  public static void main (String[] args) throws Exception
    {
      // Create some cool dudes
      Person irfan = new Person ("Irfan", "Pyarali", 25, Person.MALE);
      Person frank = new Person ("Frank", "Dokes", 99, Person.MALE);
      Person karen = new Person ("Karen", "Sanders", 59, Person.FEMALE);
      
      // Create a vector
      Vector people = new Vector ();

      // Add the cool dudes to the vector
      people.addElement (irfan);
      people.addElement (frank);
      people.addElement (karen);

      // Print the people
      System.out.println (people);
      
      // Filename where the data will be written to and read from
      String filename = "cool_dudes.txt";

      // Write the cool dudes to the file
      PersistentPeople.writePeopleToFile (people, 
                                          filename);

      // Read the cool dudes from the file
      people = PersistentPeople.readPeopleFromFile (filename);

      // Print the people again; note that this vector should contain
      // exactly the same set of people as before.
      System.out.println (people);
    }
}