i'm new to this community!
I want to ask you something about SwingWorker and its relationship with a GUI.
I know there are some answered questions about SwingWorker, and i've already read a lot of them, taking some helpful advices.
Now i'd like to post some code i wrote for a basic application which counts the number of files and folders from a specified directory.
Since the search could take a lot of time, i want a progress bar to be displayed during the process. Also, i would like users to have the possibility of stopping count process by clicking a button or simply closing the frame which contains the progress bar.
Here there are some questions on the code posted below:
- The call to execute() method for SwingWorker is the last instruction of WaitingFrame constructor: is there a better place for it?
- The dispose() method for WaitingFrame is called from SwingWorker's done() method, is it correct? If a count process is very fast, could the dispose method be called before the waiting frame is actually visible? As a result, i would have two open frames...
- Is there a better method to interrupt the process and to manage the message dialogs shown to users? I used two boolean variables, valid and interrupted, to achieve my purpose...
And here's the code:
import java.awt.*;
import java.awt.event.*;
import java.io.File;
import java.io.IOException;
import javax.swing.*;
import javax.swing.border.*;
public class CountFiles
{
public static void main(String[] args)throws Exception
{
SwingUtilities.invokeLater(new Runnable(){
public void run(){
try
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
new CountFilesFrame().setVisible(true);
}
catch(Exception ex){
ex.printStackTrace();
}
}
});
}
}
class CountFilesFrame extends JFrame
{
private JTextField field;
public CountFilesFrame()
{
super("Conta File e Cartelle");
setDefaultCloseOperation(EXIT_ON_CLOSE);
setResizable(false);
JPanel pane=(JPanel)getContentPane();
pane.setBackground(Color.WHITE);
pane.setBorder(new EmptyBorder(5,20,5,20));
JPanel center=new StyledPanel(pane,BorderLayout.CENTER,new FlowLayout(FlowLayout.LEFT,5,10)),bottom=new StyledPanel(pane,BorderLayout.SOUTH,new FlowLayout(FlowLayout.LEFT,20,0));
// Center panel
center.add(new JLabel("Cartella :"));
String text="";
try{
File folder=new File("../");
text=folder.exists()?folder.getCanonicalPath():"";
}
catch(Exception ex){}
field=new JTextField(text,25);
center.add(field);
// JTextArea
String newLine=System.getProperty("line.separator"),message="Scegliere la cartella da cui far partire la ricerca."+newLine+
"Sara' contato il numero di file e di cartelle presenti "+newLine+"nella directory inserita e in tutte le sottocartelle";
JTextArea area=new JTextArea(message);
area.setEditable(false);
area.setFont(field.getFont());
pane.add(area,BorderLayout.NORTH);
// Bottom panel
bottom.add(new JButton(new AbstractAction("Cambia Cartella"){
public void actionPerformed(ActionEvent e){
changeDirectory();
}
}));
bottom.add(new JButton(new AbstractAction("Inizia ricerca"){
public void actionPerformed(ActionEvent e){
new WaitingFrame(CountFilesFrame.this);
}
}));
pack();
setLocationRelativeTo(null);
}
public void changeDirectory()
{
JFileChooser chooser=new JFileChooser(field.getText());
chooser.setDialogTitle("Cambia Cartella");
chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
if(chooser.showDialog(this,"Scegli")==JFileChooser.APPROVE_OPTION)
{
try
{
File selected=chooser.getSelectedFile();
if(selected.exists())field.setText(selected.getCanonicalPath());
}
catch(Exception ex){}
}
}
private class WaitingFrame extends JFrame
{
private Counter counter;
public WaitingFrame(CountFilesFrame f)
{
super("Ricerca File");
setDefaultCloseOperation(DISPOSE_ON_CLOSE);
addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
stopCounter();
}
});
setResizable(false);
JPanel pane=(JPanel)getContentPane(),buttonPanel=new StyledPanel(pane,BorderLayout.SOUTH,new FlowLayout(FlowLayout.CENTER,0,10));
JLabel label=new JLabel("Conteggio in corso...",JLabel.CENTER);
label.setBorder(new EmptyBorder(0,0,10,0));
pane.add(label,BorderLayout.NORTH);
pane.setBackground(Color.WHITE);
pane.setBorder(new EmptyBorder(10,40,0,40));
JProgressBar progressBar=new JProgressBar(0,100);
progressBar.setBorderPainted(false);
progressBar.setIndeterminate(true);
pane.add(progressBar,BorderLayout.CENTER);
buttonPanel.add(new JButton(new AbstractAction("Annulla"){
public void actionPerformed(ActionEvent e){
stopCounter();
}
}));
while(pane.getSize().width!=pane.getPreferredSize().width)pack();
setLocationRelativeTo(null);
setVisible(true);
(counter=new Counter()).execute();
}
public void stopCounter()
{
counter.interrupt();
counter.cancel(true);
}
private class Counter extends SwingWorker<Void,Void>
{
private boolean valid=true,interrupted=false;
private int filesNumber=0,foldersNumber=0;
protected Void doInBackground()
{
File folder=new File(field.getText());
if(!folder.exists()||!folder.isDirectory())valid=false;
else countFiles(folder);
return null;
}
protected void done()
{
dispose();
if(interrupted)return;
else if(!valid)JOptionPane.showMessageDialog(CountFilesFrame.this,"Inserire una cartella valida","Percorso specificato errato",JOptionPane.ERROR_MESSAGE);
else JOptionPane.showMessageDialog(CountFilesFrame.this,"Sono stati trovati "+(foldersNumber-1)+" cartelle e "+filesNumber+" file","Ricerca completata",JOptionPane.INFORMATION_MESSAGE);
}
private void countFiles(File file)
{
if(file.isDirectory())
{
foldersNumber++;
for(File nested:file.listFiles())countFiles(nested);
}
else filesNumber++;
}
public void interrupt()
{
interrupted=true;
}
}
}
}
class StyledPanel extends JPanel
{
public StyledPanel(JPanel parent,String position,LayoutManager layout)
{
super(layout);
setBackground(Color.WHITE);
parent.add(this,position);
}
}
I posted all the application code, so you can try to compile and run it.
Thanks in advance for your help!
PS: i didn't change interface language, i'm sorry for that. Also, i'm sorry for my bad english...
