Приложение DirectFile

import java.awt.*;
import java.io.*;
import java.util.*;
public class DirectFile
{
  public static void main(String args[])
  {
    MainFrameWnd frame =
      new MainFrameWnd("MenuApp");
    frame.setSize(
    frame.getInsets().left +
      frame.getInsets().right  + 320,
      frame.getInsets().top  +
      frame.getInsets().bottom + 240);
    frame.show();
  }
}
class MainFrameWnd extends Frame
{
  MenuBar mbMainMenuBar;
  Menu mnFile;
  Menu mnHelp;
  boolean fDBEmpty = true;
  public MainFrameWnd(String sTitle)
  {
    super(sTitle);
    setSize(400, 200);
    setBackground(Color.yellow);
    setForeground(Color.black);
    setLayout(new FlowLayout());
    mbMainMenuBar = new MenuBar();
    mnFile = new Menu("File");
    mnFile.add("New...");
    mnFile.add("View records...");
    mnFile.add("-");
    mnFile.add("Exit");
    mnHelp = new Menu("Help");
    mnHelp.add("Content");
    mnHelp.add("-");
    mnHelp.add("About");
    mbMainMenuBar.add(mnFile);
    mbMainMenuBar.add(mnHelp);
    setMenuBar(mbMainMenuBar);
  }
  public void paint(Graphics g)
  {
    g.setFont(new Font("Helvetica",
      Font.PLAIN, 12));
    g.drawString("Frame window", 10, 70);
    super.paint(g);
  }
  public boolean handleEvent(Event evt)
  {
    if(evt.id == Event.WINDOW_DESTROY)
    {
      setVisible(false);
      System.exit(0);
      return true;
    }
    else
      return super.handleEvent(evt);
  }
  public boolean action(Event evt,
   Object obj)
  {
    MenuItem mnItem;
    if(evt.target instanceof MenuItem)
    {
      mnItem = (MenuItem)evt.target;
      if(obj.equals("Exit"))
      {
        System.exit(0);
      }
      else if(obj.equals("New..."))
      {
	if(fDBEmpty)
 	{
	  SimpleDBMS db = new SimpleDBMS(
	    "dbtest.idx", "dbtest.dat");
          db.AddRecord("Ivanov",   1000);
          db.AddRecord("Petrov",   2000);
	  db.AddRecord("Sidoroff", 3000);
          db.close();
	  fDBEmpty = false;
          MessageBox mbox;
          mbox = new MessageBox(
            "Database created",
            this, "Information", true);
	  mbox.show();
	}
      }
      else if(obj.equals("View records..."))
      {
        SimpleDBMS db = new SimpleDBMS(
	  "dbtest.idx", "dbtest.dat");
        String szRecords;
	
	szRecords =
          db.GetRecordByNumber(0) +
	  db.GetRecordByNumber(1) +
	  db.GetRecordByNumber(2);
	
        db.close();
	
        MessageBox mbox;
        mbox = new MessageBox(szRecords,
          this, "Database records", true);
	mbox.show();
      }

      else if(obj.equals("Content"))
      {
        MessageBox mbox;
        mbox = new MessageBox(
          "Item Content selected",
          this, "Dialog from Frame", true);
        mbox.show();
      }

      else if(obj.equals("About"))
      {
        MessageBox mbox;
        mbox = new MessageBox(
          "Item About selected",
          this, "Dialog from Frame", true);
        mbox.show();
      }
      else
        return false;
      return true;
    }
    return false;
  }
}
class MessageBox extends Dialog
{
  Label lbMsg;
  Button btnOK;
  public MessageBox(String sMsg,
    Frame  parent, String  sTitle,
    boolean  modal)
  {
    super(parent, sTitle, modal);
    resize(300, 100);
    setLayout(new GridLayout(2, 1));
    lbMsg = new Label(sMsg, Label.CENTER);
    add(lbMsg);
    btnOK = new Button("OK");
    add(btnOK);
  }
  public boolean handleEvent(Event evt)
  {
    if(evt.id == Event.WINDOW_DESTROY)
    {
      dispose();
      return true;
    }
    else
      return super.handleEvent(evt);
  }
  public boolean action(Event evt,
   Object obj)
  {
    Button btn;
    if(evt.target instanceof Button)
    {
      btn = (Button)evt.target;
      if(evt.target.equals(btnOK))
      {
        dispose();
      }
      else
        return false;
      return true;
    }
    return false;
  }
}
class SimpleDBMS
{
  RandomAccessFile idx;
  RandomAccessFile dat;
  long idxFilePointer = 0;
  public SimpleDBMS(String IndexFile,
   String DataFile)
  {
    try
    {
      idx = new RandomAccessFile(
        IndexFile, "rw");
      dat = new RandomAccessFile(
        DataFile, "rw");
    }
    catch(Exception ioe)
    {
      System.out.println(ioe.toString());
    }
  }
  public void close()
  {
    try
    {
      idx.close();
      dat.close();
    }
    catch(Exception ioe)
    {
      System.out.println(ioe.toString());
    }
  }
  public void AddRecord(String name,
     int account)
  {
    try
    {
      idx.seek(idx.length());
      dat.seek(dat.length());
      idxFilePointer = dat.getFilePointer();
      idx.writeLong(idxFilePointer);
      dat.writeBytes(name+ "\r\n");
      dat.writeInt(account);
    }
    catch(Exception ioe)
    {
      System.out.println(ioe.toString());
    }
  }
  public String GetRecordByNumber(long nRec)
  {
    String sRecord = "<empty>";

    try
    {
      Integer account;
      String str = null;
      idx.seek(nRec * 8);
      idxFilePointer = idx.readLong();
      dat.seek(idxFilePointer);
      str = dat.readLine();
      account = new Integer(dat.readInt());
      sRecord = new String("> " +
       account + ", " + str);
    }
    catch(Exception ioe)
    {
      System.out.println(ioe.toString());
    }
    return sRecord;
  }
}

SimpleDBMS db = new SimpleDBMS(
  "dbtest.idx", "dbtest.dat");

db.AddRecord("Ivanov",   1000);
db.AddRecord("Petrov",   2000);
db.AddRecord("Sidoroff", 3000);

db.close();

SimpleDBMS db = new SimpleDBMS(
  "dbtest.idx", "dbtest.dat");

String szRecords;

szRecords = db.GetRecordByNumber(0) +
  db.GetRecordByNumber(1) +
  db.GetRecordByNumber(2);

db.close();

MessageBox mbox;
mbox = new MessageBox(szRecords,
  this, "Database records", true);
mbox.show();

idx = new RandomAccessFile(IndexFile, "rw");
dat = new RandomAccessFile(DataFile, "rw");

idx.close();
dat.close();

idx.seek(idx.length());
dat.seek(dat.length());

idxFilePointer = dat.getFilePointer();
idx.writeLong(idxFilePointer);

dat.writeBytes(name + "\r\n");
dat.writeInt(account);

idx.seek(nRec * 8);

idxFilePointer = idx.readLong();
dat.seek(idxFilePointer);

str = dat.readLine();
account = new Integer(dat.readInt());

sRecord = new String("> " +
  account + ", " + str);