/*
Simple Java serialization example for cs585
Demo program reads and writes a  file of Items.

Java's Serializable tutorial is at:
http://java.sun.com/docs/books/tutorial/essential/io/providing.html

Serialization must first write a file before it can read a file.

To run demo

java SerializableDemo <file> [<boolean>]

example:

java SerializableDemo filename false    // create filename save items
java SerializableDemo filename          // open filename read it and write it


Mike Barnes
9/19/03
*/

import java.io.*;
import java.util.*;  // Vector

public class SerializableDemo implements Serializable {

  Vector items;

  class Item  implements Serializable {
    public String descript, note;
    public boolean hasNote;

    public Item() {
      hasNote = false;
      descript = note = null; 
      }

    public Item(String description, String aNote) {
      hasNote = true;
      descript = description;
      note = aNote;
      }

    public Item(String description) {
      hasNote = false;
      descript = description;
      note = null;
      }

    public String toString() {
      String str = new String(descript + "\n" + hasNote + "\n" + note + "\n");
      return str;}
  
    } // Item

  public SerializableDemo() {
    items = new Vector();
    }

  // read all the items from open file file and place in vector items
  public void readItems(String fileName) throws IOException  {
    ObjectInputStream fin = null;  // file to read
    boolean done = false;
    Item item = null;
    // open file to read
    System.out.println("Reading");
    try {
      fin = new ObjectInputStream( new FileInputStream(fileName));
      }
    catch(IOException e) {
      System.out.println(fileName + " not found.");
      System.exit(0);
      }
    // read from file
    System.out.print("File " + fileName + " ");
    done = false;
    while(!done) {
      try {
        item = (Item) fin.readObject();
        items.addElement(item);
        System.out.print(". ");  // show progress in reading file
        }
      catch (EOFException eof) {
        done = true;
        System.out.println("at end of file, done");
        System.out.println();
        }
      catch (ClassNotFoundException cnf) {
        System.out.println("Item class not found, exit");
        fin.close();
        System.exit(0);
        }
      catch (IOException e) { 
        System.out.println("Error reading items");
        fin.close();
        System.exit(0); 
        }
      }
    }


  public void writeItems(String fileName) throws IOException  {
    ObjectOutputStream fout = null;    // file to write
    Item item;
    System.out.println("Writing");
    try {
      fout = new ObjectOutputStream( new FileOutputStream(fileName));
      }
    catch(IOException e) {
      System.out.println(fileName + " not found");
      System.exit(0);
      }
    // write to file
    System.out.print("File " + fileName + "  ");
    int count = items.size();
    for(int i = 0; i < count; i++) {
      item = (Item) items.elementAt(i);
      fout.writeObject(item);
      fout.flush();
      System.out.print(". ");
      }
    fout.close();
    System.out.println(count + " items wrote");
    }

  public void createItems() {
    items.addElement(new Item("listen to Pat Metheny"));
    items.addElement(new Item("585 p1", 
      "Need to get a plan for how to complete the first project in 585.  Perhaps I can look at some examples and then mock up some stuff."));
    items.addElement(new Item("wash clothes"));
    items.addElement(new Item("write home"));
    items.addElement(new Item("organize hard disk",
      "need to have separate subdirectories for each version of my projects in each of the classes that I am taking."));
    }

  public void showItems() {
    Enumeration enum;
    System.out.println("Show " + items.size() + " items read");
    System.out.println();
    enum = items.elements();
    while (enum.hasMoreElements()) 
      System.out.println( enum.nextElement());
    }

  // open a file of items to read into a vector
  // show the vector of items read
  // write the vector of items to a file

  public static void main (String[] args) throws IOException {
    boolean done = false;
    String fileName = null;

    SerializableDemo demo = new SerializableDemo();
    System.out.println();
    switch (args.length) {
      case 1 :
        fileName = args[0];
        demo.readItems(fileName);
        demo.showItems();
        demo.writeItems(fileName);
        break;
      case 2 :
        fileName = args[0];
        demo.createItems();
        demo.showItems();
        demo.writeItems(fileName);
        break;
      default : 
        System.out.println("Usage:");
        System.out.println("\t java SerializableDemo <file> [<boolean>]");
        System.out.println("\t examples:");
        System.out.println("\t\tjava SerializableDemo filename");
        System.out.println("\t\t\t // open filename read it and write it");
        System.out.println("\t\t java SerializableDemo filename false");
        System.out.println("\t\t\t // create filename and save items");
      }
    }
  }