jmessagesave.java

an instant messenger written in java (client)

import java.io.*;
import javax.swing.*;
import javax.swing.filechooser.FileFilter;

public class JMessageSave
{
    private JFileChooser fileChooser;
    private JPrivateMessage frame;
    private JEditorPane txtDisplay;
    private File file = null;
    private int result;
    
    // Constructor
    public JMessageSave(JPrivateMessage frame, JEditorPane txtDisplay)
    {
        this.frame = frame;
        this.txtDisplay = txtDisplay;
        fileChooser = new JFileChooser();
        fileChooser.setDialogTitle("Save Conversation");
        fileChooser.setApproveButtonText("Save");
        fileChooser.addChoosableFileFilter(new txtFileFilter("html"));   // class txtFileFilter will be defined below
        this.saveDialog();   // Function to active SAVE
    }

    public void saveDialog()
    {
        FileOutputStream fileout = null; 
    
        result = fileChooser.showSaveDialog(frame);
        
        if (result == JFileChooser.APPROVE_OPTION)
        {
            file = fileChooser.getSelectedFile();    
        }
        
        if (file != null)
        {
            try
            {
                fileout = new FileOutputStream(file);    // establish output stream
            }    
            catch (FileNotFoundException e)
            {
                JOptionPane.showMessageDialog(null, "File not existed", "File Error", JOptionPane.ERROR_MESSAGE);
                return;  
            }
        
            // if output stream is ok, then grap the text from the txtDisplay
            String txtContent = txtDisplay.getText();
            
            try
            {
                fileout.write(txtContent.getBytes());    // specify the size writing into the stream
            }
            catch (IOException ex)
            {
                JOptionPane.showMessageDialog(null, "Error in writing file", "File Error", JOptionPane.ERROR_MESSAGE);
            }
            
            // The following code must be executed
            finally
            {
                try
                {
                    if (fileout != null)
                        fileout.close();
                }
                catch (IOException ex)
                {
                    JOptionPane.showMessageDialog(null, "Error!", "File Error", JOptionPane.ERROR_MESSAGE);
                }
            }
        } 
    }
}

class txtFileFilter extends FileFilter
{
    String extend;
     
    // Constructor   
    public txtFileFilter(String extend)    // input "txt" here
    {
        this.extend = extend;    // the pre-set extension for the files ( _____.txt )
    }
    
    public boolean accept(File file)
    {
        if (file.isDirectory())
           return true;
       
        
        String fileName = file.getName();
        int index = fileName.lastIndexOf('.');
        if ((index>0) && (index<fileName.length()-1))
        {
            String in_extend = fileName.substring(index+1).toLowerCase();   // extract the extension of the input file
            if (in_extend.equals(extend))
                return true;
        }
        
        return false;
    }  
    
    public String getDescription()
    {
    	return "HTML (*.html)";	
    }
}