一个JTextArea的重构

package fr.itris.glips.svgeditor.properties.database;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.awt.event.InputEvent;

import java.awt.event.MouseAdapter;

import java.awt.event.MouseEvent;

import javax.swing.JCheckBoxMenuItem;

import javax.swing.JMenuItem;

import javax.swing.JPopupMenu;

import javax.swing.JTextArea;

import javax.swing.KeyStroke;

import javax.swing.SwingUtilities;

import javax.swing.event.ChangeEvent;

import javax.swing.event.ChangeListener;

import javax.swing.event.DocumentEvent;

import javax.swing.event.DocumentListener;

 

class MyTextArea extends JTextArea {

private JPopupMenu pop = null; // 弹出菜单

JCheckBoxMenuItem lock = null;

private JMenuItem clear = null; // 三个功能菜单

StringBuffer buf = new StringBuffer();

boolean locked = false;

private static final int MAX_LINE_NUM=2000;

public MyTextArea() {

super();

this.setEnabled(false);

this.setEditable(true);

pop = new JPopupMenu();

lock = new JCheckBoxMenuItem("锁定");

lock.setSelected(locked);

lock.setName("锁定");

pop.add(lock);

pop.add(clear = new JMenuItem("清空"));

this.getDocument().addDocumentListener(new DocumentListener() {

@Override

public void insertUpdate(DocumentEvent e) {

SwingUtilities.invokeLater(new Runnable() {

public void run() {

if (MyTextArea.this.getLineCount() >= MAX_LINE_NUM) {

int end = 0;

try {

end = MyTextArea.this.getLineEndOffset(MAX_LINE_NUM);

} catch (Exception e) {

}

MyTextArea.this.replaceRange("", 0, end);

}

MyTextArea.this.setCaretPosition(MyTextArea.this.getText().length());

}

});

}

public void removeUpdate(DocumentEvent evt) {

}

public void changedUpdate(DocumentEvent evt) {

}

});

this.addMouseListener(new MouseAdapter() {

@Override

public void mousePressed(MouseEvent e) {

if (e.getButton() == MouseEvent.BUTTON3) {

pop.show(MyTextArea.this, e.getX(), e.getY());

}

}

});

PopupMenuListener popupMenuListener=new PopupMenuListener();

lock.addChangeListener(new LockedChangeListener());

clear.addActionListener(popupMenuListener);

lock.setAccelerator(KeyStroke.getKeyStroke('L',

InputEvent.CTRL_MASK));

clear.setAccelerator(KeyStroke.getKeyStroke('C',

InputEvent.CTRL_MASK));

}

@Override

public void append(String str) {

synchronized (this) {

// ++lineNo + " 、" 

String line = str + "\r\n";

if (!locked) {

super.append(line);

} else {

buf.append(line);

}

}

}

public synchronized void lock() {

if(!locked){

locked = true;

}

}

public synchronized void unLock() {

if(locked){

locked = false;

if (buf.length() > 0) {

this.append(buf.toString());

buf.delete(0, buf.length());

}

}

}

public synchronized void setLock(boolean locked) {

if (locked) {

lock();

} else {

unLock();

}

}

public synchronized void clear(){

this.setText("");

}

private class LockedChangeListener implements ChangeListener {

public void stateChanged(ChangeEvent event) {

setLock(lock.isSelected());

}

}

private class PopupMenuListener implements ActionListener {

@Override

public void actionPerformed(ActionEvent e) {

// TODO Auto-generated method stub

String str = e.getActionCommand();

if (str.equals(clear.getText())) {  

clear();

}

}

}

 

}