I have Developed a Swing Based Application based on JTextArea.I Add Undo and Redo Options to My Application.I have Three Menu Items,Open,Rollback and Redo.My problem is when I open more than one Empty Documents and write some text on opened Documents.When I click on Rollback the contents of all opened Documents are removed/rollback not only focus Document.Please Check it.Thank you. My Code:
public class UndoAndRedo extends javax.swing.JFrame {
int i = 0;
JTextArea textArea;
JScrollPane scrollPane;
int tabCount=0;
UndoManager undoManager = new UndoManager();
public UndoAndRedo() {
initComponents();
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
tp = new javax.swing.JTabbedPane();
jMenuBar1 = new javax.swing.JMenuBar();
fileMenu = new javax.swing.JMenu();
open = new javax.swing.JMenuItem();
rollback = new javax.swing.JMenuItem();
redo = new javax.swing.JMenuItem();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
fileMenu.setText("File");
open.setText("Open");
open.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
openActionPerformed(evt);
}
});
fileMenu.add(open);
rollback.setText("Rollback");
rollback.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
rollbackActionPerformed(evt);
}
});
fileMenu.add(rollback);
redo.setText("Redo");
redo.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
redoActionPerformed(evt);
}
});
fileMenu.add(redo);
jMenuBar1.add(fileMenu);
setJMenuBar(jMenuBar1);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 400, Short.MAX_VALUE)
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(tp, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 279, Short.MAX_VALUE)
);
pack();
}
private void openActionPerformed(java.awt.event.ActionEvent evt) {
textArea=new JTextArea();
textArea.setFont(new java.awt.Font("Miriam Fixed", 0, 13));
textArea.setDocument(new CustomUndoPlainDocument());
scrollPane=new JScrollPane(textArea);
tabCount++;
tp.addTab("Document "+tabCount, null, scrollPane, "Document "+tabCount);
try {
tp.setSelectedIndex(tabCount-1);
}
catch(IndexOutOfBoundsException i) {
}
textArea.requestFocus();
textArea.setCaretPosition(0);
textArea.getDocument().addUndoableEditListener(undoManager);
}
private void rollbackActionPerformed(java.awt.event.ActionEvent evt) {
if (undoManager.canUndo()) {
undoManager.undo();
}
}
private void redoActionPerformed(java.awt.event.ActionEvent evt) {
if (undoManager.canRedo()) {
undoManager.redo();
}
}
public static void main(String args[]) {
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(UndoAndRedo.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(UndoAndRedo.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(UndoAndRedo.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(UndoAndRedo.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new UndoAndRedo().setVisible(true);
}
});
}
private javax.swing.JMenu fileMenu;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem open;
private javax.swing.JMenuItem redo;
private javax.swing.JMenuItem rollback;
private javax.swing.JTabbedPane tp;
class CustomUndoPlainDocument extends PlainDocument {
private CompoundEdit compoundEdit;
@Override protected void fireUndoableEditUpdate(UndoableEditEvent e) {
if (compoundEdit == null) {
super.fireUndoableEditUpdate(e);
} else {
compoundEdit.addEdit(e.getEdit());
}
}
@Override public void replace(
int offset, int length,
String text, AttributeSet attrs) throws BadLocationException {
if (length == 0) {
super.replace(offset, length, text, attrs);
} else {
compoundEdit = new CompoundEdit();
super.fireUndoableEditUpdate(new UndoableEditEvent(this, compoundEdit));
super.replace(offset, length, text, attrs);
compoundEdit.end();
compoundEdit = null;
}
}
}
}
