Javase based on the AWT Notepad implementation

{Feature Description}
The NoteBook class is a basic class for Notepad, which has the basic functions of Notepad, including:
Open the file, save the file and copy, paste, delete the text and so on.
The program consists of adding a menu bar for a window, adding a menu to the menu bar, adding a menu item to the menu bar, and adding the appropriate listener for each menu item to complete the action. In addition, it also includes reading and saving the contents of the file.

{Instance Diagram}


{Related Code}

 PackageSup.orange.learn;Importjava.awt.*;ImportJava.awt.datatransfer.Clipboard;ImportJava.awt.datatransfer.DataFlavor;Importjava.awt.datatransfer.StringSelection;Importjava.awt.datatransfer.Transferable;Importjava.awt.event.ActionEvent;ImportJava.awt.event.ActionListener;ImportJava.awt.event.WindowAdapter;Importjava.awt.event.WindowEvent;ImportJava.io.File;ImportJava.io.FileReader;ImportJava.io.FileWriter;Importjava.io.IOException;/*** Created by Re-x on 11/3/14.*/ Public classNoteBookextendsFrameImplementsactionlistener{MenuBar MenuBar=NewMenuBar (); TextArea TextArea=NewTextArea (); //File MenuMenu Filemenu =NewMenu ("File"); MenuItem NewItem=NewMenuItem ("New"); MenuItem OpenItem=NewMenuItem ("Open"); MenuItem SaveItem=NewMenuItem ("Save"); MenuItem Saveasitem=NewMenuItem ("Save as"); MenuItem Exititem=NewMenuItem ("Exit"); //Edit MenuMenu Editmenu =NewMenu ("Edit"); MenuItem SelectItem=NewMenuItem ("Select All"); MenuItem CopyItem=NewMenuItem ("Copy"); MenuItem Cutitem=NewMenuItem ("Cut"); MenuItem Pasteitem=NewMenuItem ("Paste"); String FileName= "NoName.txt"; Toolkit Toolkit=Toolkit.getdefaulttoolkit (); Clipboard Clipboard=Toolkit.getsystemclipboard (); //Create and init Open File Dialog && Save File Dialog    PrivateFileDialog OpenFileDialog =NewFileDialog ( This, "Open File", Filedialog.load); PrivateFileDialog Saveasfiledialog =NewFileDialog ( This, "Save as", Filedialog.save);  PublicNoteBook () {Settitle ("NotePad"); SetFont (NewFont ("Times New Roman", Font.plain, 12));        SetBackground (Color.gray); SetSize (600, 400);        Filemenu.add (NewItem);        Filemenu.add (OpenItem);        Filemenu.addseparator ();        Filemenu.add (SaveItem);        Filemenu.add (Saveasitem);        Filemenu.addseparator ();        Filemenu.add (Exititem);        Editmenu.add (SelectItem);        Editmenu.addseparator ();        Editmenu.add (CopyItem);        Editmenu.add (Cutitem);        Editmenu.add (Pasteitem);        Menubar.add (Filemenu);        Menubar.add (Editmenu);        Setmenubar (MenuBar);        Add (TextArea); Addwindowlistener (NewWindowadapter () {@Override Public voidwindowclosing (windowevent e) {Super. windowclosing (e);                Dispose (); System.exit (0);        }        }); Newitem.addactionlistener ( This); Openitem.addactionlistener ( This); Saveitem.addactionlistener ( This); Saveasitem.addactionlistener ( This); Exititem.addactionlistener ( This); Selectitem.addactionlistener ( This); Copyitem.addactionlistener ( This); Cutitem.addactionlistener ( This); Pasteitem.addactionlistener ( This); }     Public Static voidMain (string[] args) {Frame frame=NewNoteBook (); Dimension screensize= Toolkit.getdefaulttoolkit (). Getscreensize ();//Get screen sizeDimension framesize = Frame.getsize ();//Get frame size        if(Framesize.height >screensize.height) {framesize.height=Screensize.height; }        if(Framesize.width >screensize.width) {framesize.width=Screensize.width; } frame.setlocation (Screensize.width-framesize.width)/2, (screensize.height-framesize.height)/2); Frame.setvisible (true); }     Public voidactionperformed (ActionEvent e) {Object EventSource=E.getsource (); //judge which MenuItem is the source        if(EventSource = =newitem) {Textarea.settext (""); }        Else if(EventSource = =OpenItem) {openfiledialog.setvisible (true); FileName= Openfiledialog.getdirectory () +Openfiledialog.getfile (); if(FileName! =NULL) {readFile (fileName); }        }        Else if(EventSource = =SaveItem) {            if(FileName! =NULL) {WriteFile (fileName); }        }        Else if(EventSource = =Saveasitem) {saveasfiledialog.setvisible (true); FileName= Saveasfiledialog.getdirectory () +Saveasfiledialog.getfile (); if(FileName! =NULL) {WriteFile (fileName); }        }        Else if(EventSource = =SelectItem)        {Textarea.selectall (); }        Else if(EventSource = =CopyItem) {String text=Textarea.getselectedtext (); StringSelection selection=Newstringselection (text); Clipboard.setcontents (Selection,NULL); }        Else if(EventSource = =Cutitem) {String text=Textarea.getselectedtext (); StringSelection selection=Newstringselection (text); Clipboard.setcontents (Selection,NULL); Textarea.replacerange ("", Textarea.getselectionstart (), Textarea.getselectionend ()); }        Else if(EventSource = =Pasteitem) {Transferable Contents= Clipboard.getcontents ( This); if(contents = =NULL) {                return; } String Text= ""; Try{text=(String) contents.gettransferdata (Dataflavor.stringflavor); }            Catch(Exception ex) {ex.printstacktrace ();        } textarea.replacerange (text, Textarea.getselectionstart (), Textarea.getselectionend ()); }        Else if(EventSource = =Exititem) {System.exit (0); }    }     Public voidreadFile (String fileName) {Try{File File=NewFile (fileName); FileReader Readin=Newfilereader (file); intSize = (int) file.length (); intCharsread = 0; Char[] content =New Char[size];  while(Readin.ready ()) {Charsread+ = Readin.read (content, Charsread, size-charsread);            } readin.close (); Textarea.settext (NewString (content, 0, Charsread)); }        Catch(IOException e) {e.printstacktrace (); }    }     Public voidWriteFile (String fileName) {Try{File File=NewFile (fileName); FileWriter Writeout=NewFileWriter (file);            Writeout.write (Textarea.gettext ());        Writeout.close (); }        Catch(IOException e) {e.printstacktrace (); }    }}

Javase based on the AWT Notepad implementation