用Java编写的记事本程序

　　这个学期，我们学习了Java编程，期末之时老师要我们编个记事本作为这门课程的课程设计，我写了一个，大体上的功能都实现了，只有"撤销"的功能没有实现，请各位大虾指点一下，“撤销”的算法，不甚感激！
特将记事本的源码附下，请大家指点，看还有没有更简洁高效的算法，请不要吝啬，我的E-mail:yangyong@ccsu.cn,欢迎大家来信指点！

/*
*
*题目：记事本程序
*Author: Jeason
*
* 2004-12-20
*
**/
package jeason;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import java.io.*;
import java.util.*;
import java.text.*;

public class Jsb{

///
boolean dirty=true;
String filename="";
String strtext="";

///////////////////////////////////
////////// Menu ////////////////
///////////////////////

JFrame frame=new JFrame("我的记事本");
JPopupMenu pop=new JPopupMenu("弹出");
JTextArea text=new JTextArea();
JLabel statubar=new JLabel("状态栏");
JMenuBar Mbar=new JMenuBar();
JFileChooser jFileChooser1=new JFileChooser();

JColorChooser jColor=new JColorChooser();

JMenu jFile=new JMenu("文件");
JMenu jEdit=new JMenu("编辑");
JMenu jFormat=new JMenu("格式");
JMenu jHelp=new JMenu("帮助");

JMenuItem jnew=new JMenuItem("新建(N)");

public Jsb(){ ///无参数的构造函数

///
this.dirty=false;
/////

final BorderLayout borderLayout1=new BorderLayout();

frame.setSize(600,500);//
frame.addWindowListener(new Jsb_frame_closingAdapter(this));

JPanel panel=new JPanel();
panel.setLayout(borderLayout1);//布局
panel.add(new JScrollPane(text));//滚动条
panel.add(statubar,borderLayout1.SOUTH);

frame.getContentPane().add(panel);
//
frame.setJMenuBar(Mbar); //将主菜单添加到窗体中

/*
* jnew
**/
//jnew
jnew.addActionListener(new File_new_actionAdapter(this));
jnew.setMnemonic(´N´);//N上下划线
jnew.setAccelerator(KeyStroke.getKeyStroke(´N´,java.awt.Event.CTRL_MASK,true));
//快捷方式

/*
* jopen
**/
JMenuItem jopen=new JMenuItem("打开(O)");//jopen
jopen.addActionListener(new File_open_actionAdapter(this));
jopen.setMnemonic(´O´);
jopen.setAccelerator(KeyStroke.getKeyStroke(´O´,java.awt.Event.CTRL_MASK,true));

/*
* jsave
**/
JMenuItem jsave=new JMenuItem("保存(S)");
jsave.addActionListener(new File_save_actionAdapter(this));
jsave.setMnemonic(´S´);
jsave.setAccelerator(KeyStroke.getKeyStroke(´S´,java.awt.Event.CTRL_MASK,true));

/*
* jsave as
**/
JMenuItem jsaveas=new JMenuItem("另存为...");
jsaveas.addActionListener(new File_saveas_actionAdapter(this));
/*
* jquite
**/

JMenuItem jquite=new JMenuItem("关闭(Q)");
jquite.addActionListener(new File_quite_actionAdapter(this));
jquite.setMnemonic(´Q´);
jquite.setAccelerator(KeyStroke.getKeyStroke(´Q´,java.awt.Event.CTRL_MASK,true));

//------------------------------------
// jFile code of end
//--------------------------------------

/**
* jEdit code
*/
//jundo
JMenuItem jundo=new JMenuItem("撤销(U)");
jundo.addActionListener(new Edit_undo_actionAdapter(this));
jundo.setMnemonic(´U´);
jundo.setAccelerator(KeyStroke.getKeyStroke(´U´,java.awt.Event.CTRL_MASK,true));

/*
* jcut
**/
JMenuItem jcut=new JMenuItem("剪切(X)");
jcut.addActionListener(new Edit_cut_actionAdapter(this));
jcut.setMnemonic(´X´);
jcut.setAccelerator(KeyStroke.getKeyStroke(´X´,java.awt.Event.CTRL_MASK,true));

/*
* jcopy
**/
JMenuItem jcopy=new JMenuItem("复制(C)");
jcopy.addActionListener(new Edit_copy_actionAdapter(this));
jcopy.setMnemonic(´C´);
jcopy.setAccelerator(KeyStroke.getKeyStroke(´C´,java.awt.Event.CTRL_MASK,true));

/*
* jpaste
**/
JMenuItem jpaste=new JMenuItem("粘贴(V)");
jpaste.addActionListener(new Edit_paste_actionAdapter(this));
jpaste.setMnemonic(´V´);
jpaste.setAccelerator(KeyStroke.getKeyStroke(´V´,java.awt.Event.CTRL_MASK,true));

/*
* jdelete
**/
JMenuItem jdelete=new JMenuItem("删除(D)");
jdelete.addActionListener(new Edit_delete_actionAdapter(this));
jdelete.setMnemonic(´D´);
jdelete.setAccelerator(KeyStroke.getKeyStroke(´D´,java.awt.Event.CTRL_MASK,true));

/*
* jfind
**/
JMenuItem jfind=new JMenuItem("查找(F)");
jfind.addActionListener(new Edit_find_actionAdapter(this));
jfind.setMnemonic(´F´);
jfind.setAccelerator(KeyStroke.getKeyStroke(´F´,java.awt.Event.CTRL_MASK,true));

/*
* jreplace
**/
JMenuItem jreplace=new JMenuItem("替换(R)");
jreplace.addActionListener(new Edit_replace_actionAdapter(this));
jreplace.setMnemonic(´R´);
jreplace.setAccelerator(KeyStroke.getKeyStroke(´R´,java.awt.Event.CTRL_MASK,true));

/*
*jselectall
**/
JMenuItem jselectall=new JMenuItem("全选(A)");
jselectall.addActionListener(new Edit_selectall_actionAdapter(this));
jselectall.setMnemonic(´A´);
jselectall.setAccelerator(KeyStroke.getKeyStroke(´A´,java.awt.Event.CTRL_MASK,true));

/*
* jdate
**/
JMenuItem jdate=new JMenuItem("日期/时间(T)");
jdate.addActionListener(new Edit_timedate_actionAdapter(this));
jdate.setMnemonic(´T´);
jdate.setAccelerator(KeyStroke.getKeyStroke(´T´,java.awt.Event.CTRL_MASK,true));

//------------------------------
// jEdit code of end
//
//-----------------------------

/*
* jWord
**/
JMenuItem jword=new JMenuItem("自动换行");
jword.addActionListener(new Format_word_actionAdapter(this));

/*
* jfont
**/
JMenuItem jfont=new JMenuItem("字体..");
jfont.addActionListener(new Format_font_actionAdapter(this));

/*
* jcolor
**/
JMenuItem jcolor=new JMenuItem("颜色...");
jcolor.addActionListener(new Format_color_actionAdapter(this));

//--------------------------------------------------
// jFormat code of end
//--------------------------------------------------

/*
* jabout
**/
JMenuItem jabout=new JMenuItem("关于作者(A)");
jabout.addActionListener(new Help_about_actionAdapter(this));
jabout.setMnemonic(´A´);
jabout.setAccelerator(KeyStroke.getKeyStroke(´A´,java.awt.Event.CTRL_MASK,true));

//-------------------------------------------------
// jHelp code of end
//------------------------------------------------------

/*************************************************
*------------------------------------------------
* PopupMenuItem
*------------------------------------------------
*************************************************/
/*
* pundo
**/
JMenuItem pundo=new JMenuItem("撤销(U)");
pundo.addActionListener(new Pop_undo_actionAdapter(this));
pundo.setMnemonic(´U´);
pundo.setAccelerator(KeyStroke.getKeyStroke(´U´,java.awt.Event.CTRL_MASK,true));

/*
* pcut
**/
JMenuItem pcut=new JMenuItem("剪切(X)");
pcut.addActionListener(new Pop_cut_actionAdapter(this));
pcut.setMnemonic(´X´);
pcut.setAccelerator(KeyStroke.getKeyStroke(´X´,java.awt.Event.CTRL_MASK,true));

/*
* pcopy
**/
JMenuItem pcopy=new JMenuItem("复制(C)");
pcopy.addActionListener(new Pop_copy_actionAdapter(this));
pcopy.setMnemonic(´C´);
pcopy.setAccelerator(KeyStroke.getKeyStroke(´C´,java.awt.Event.CTRL_MASK,true));

/*
* ppaste
**/
JMenuItem ppaste=new JMenuItem("粘贴(V)");
ppaste.addActionListener(new Pop_paste_actionAdapter(this));
ppaste.setMnemonic(´V´);
ppaste.setAccelerator(KeyStroke.getKeyStroke(´V´,java.awt.Event.CTRL_MASK,true));

/*
*pdelete
**/
JMenuItem pdelete=new JMenuItem("删除(D)");
pdelete.addActionListener(new Pop_delete_actionAdapter(this));
pdelete.setMnemonic(´D´);
pdelete.setAccelerator(KeyStroke.getKeyStroke(´D´,java.awt.Event.CTRL_MASK,true));

////////
///////////// text////////////////////////////////////////
text.setDoubleBuffered(false);
text.setToolTipText("杨勇的记事本");
text.setVerifyInputWhenFocusTarget(true);
text.setText("");

text.addCaretListener(new Jsb_text_caretAdapter(this));
text.addMouseListener(new Jsb_text_mouseAdapter(this));
text.addAncestorListener(new Jsb_text_ancestorAdapter(this));

//////////////////////////////////////////////////////////
Mbar.add(jFile);
Mbar.add(jEdit);
Mbar.add(jFormat);
Mbar.add(jHelp);

jFile.add(jnew);
jFile.add(jopen);
jFile.addSeparator();
jFile.add(jsave);
jFile.add(jsaveas);
jFile.addSeparator();
jFile.add(jquite);

jEdit.add(jundo);
jEdit.addSeparator();
jEdit.add(jcut);
jEdit.add(jcopy);
jEdit.add(jpaste);
jEdit.add(jdelete);
jEdit.addSeparator();
jEdit.add(jfind);
jEdit.add(jreplace);
jEdit.addSeparator();
jEdit.add(jselectall);
jEdit.add(jdate);

jFormat.add(jword);
jFormat.addSeparator();
jFormat.add(jfont);
jFormat.addSeparator();
jFormat.add(jcolor);

jHelp.add(jabout);

pop.add(pundo);
pop.addSeparator();
pop.add(pcut);
pop.add(pcopy);
pop.add(ppaste);
pop.add(pdelete);

frame.setVisible(true);

}
/************************************************************
//////////////////////Event/////////////////////////////////
**************************************************************/

public void frame_windowclose_windowClosing(WindowListener e){
this.close();
}
/////////////////////////////////////////////////////////
public void text_mouseClicked(MouseEvent e){
if(e.getModifiers()==InputEvent.BUTTON3_MASK){
pop.show((Component)e.getSource(),e.getX(),e.getY());
}
}
public void text_ancestorAdded(AncestorEvent e){
this.dirty=false;
this.newtext();
}
public void text_caretUpdate(CaretEvent e)
{
this.dirty=true;
//this.statubar.setText(this.text.getText());
}
///////////// File /////////////////////////////////////
public void File_open_actionPerformed(ActionEvent e){
//打开的事件
this.opentext();
}

public void File_new_actionPerformed(ActionEvent e){
///新建的事件
this.newtext();
}

public void File_save_actionPerformed(ActionEvent e){
//保存的事件
this.save();
}

public void File_saveas_actionPerformed(ActionEvent e){
//另存为
this.saveas();
}
public void File_quite_actionPerformed(ActionEvent e){
this.close();
}
////////////////// Edit /////////////////////////////////////
public void Edit_undo_actionPerformed(ActionEvent e){
//撤销
this.undo();
}
public void Edit_cut_actionPerformed(ActionEvent e){
//剪切
this.cut();
}
public void Edit_copy_actionPerformed(ActionEvent e){
//复制
this.copy();
}
public void Edit_paste_actionPerformed(ActionEvent e){
//粘贴
this.paste();
}
public void Edit_delete_actionPerformed(ActionEvent e){
//删除
this.delete();
}
public void Edit_find_actionPerformed(ActionEvent e){
//查找
int cu=this.text.getCaretPosition();
int end=this.text.getText().length();
FindDlg fd=new FindDlg(frame,"查找",true);
fd.show();
String str=fd.getFindStr().trim();

if(fd.getFlag()){
this.nextFindStr(str,cu,end);
}else{
this.upFindStr(str,cu);
}

}
public void Edit_replace_actionPerformed(ActionEvent e){
//替换
int cu=this.text.getCaretPosition();
int end=this.text.getText().length();
ReplaceDlg rd=new ReplaceDlg(frame,"替换",true);
rd.show();
this.replaceStr(rd.findStr().trim(),rd.replaceStr().trim(),cu,end);
}
public void Edit_selectall_actionPerformed(ActionEvent e){
//全选
this.text.setSelectionStart(0);
this.text.setSelectionEnd(this.text.getText().length());
}
public void Edit_timedate_actionPerformed(ActionEvent e){
//时间日期
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
this.text.append("