A program to test a progress monitor input stream. : ProgressMonitor « Swing JFC « Java

1. Java
2. Swing JFC
3. ProgressMonitor

A program to test a progress monitor input stream.

 
/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Scanner;

import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.ProgressMonitorInputStream;
import javax.swing.SwingWorker;

/**
 * A program to test a progress monitor input stream.
 * @version 1.04 2007-08-01
 * @author Cay Horstmann
 */
public class ProgressMonitorInputStreamTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(new Runnable()
         {
            public void run()
            {
               JFrame frame = new TextFrame();
               frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               frame.setVisible(true);
            }
         });
   }
}

/**
 * A frame with a menu to load a text file and a text area to display its contents. The text area is
 * constructed when the file is loaded and set as the content pane of the frame when the loading is
 * complete. That avoids flicker during loading.
 */
class TextFrame extends JFrame
{
   public TextFrame()
   {
      setTitle("ProgressMonitorInputStreamTest");
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);

      textArea = new JTextArea();
      add(new JScrollPane(textArea));

      chooser = new JFileChooser();
      chooser.setCurrentDirectory(new File("."));

      JMenuBar menuBar = new JMenuBar();
      setJMenuBar(menuBar);
      JMenu fileMenu = new JMenu("File");
      menuBar.add(fileMenu);
      openItem = new JMenuItem("Open");
      openItem.addActionListener(new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               try
               {
                  openFile();
               }
               catch (IOException exception)
               {
                  exception.printStackTrace();
               }
            }
         });

      fileMenu.add(openItem);
      exitItem = new JMenuItem("Exit");
      exitItem.addActionListener(new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               System.exit(0);
            }
         });
      fileMenu.add(exitItem);
   }

   /**
    * Prompts the user to select a file, loads the file into a text area, and sets it as the content
    * pane of the frame.
    */
   public void openFile() throws IOException
   {
      int r = chooser.showOpenDialog(this);
      if (r != JFileChooser.APPROVE_OPTION) return;
      final File f = chooser.getSelectedFile();

      // set up stream and reader filter sequence
      
      FileInputStream fileIn = new FileInputStream(f);
      ProgressMonitorInputStream progressIn = new ProgressMonitorInputStream(this, "Reading "
            + f.getName(), fileIn);
      final Scanner in = new Scanner(progressIn);

      textArea.setText("");

      SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>()
         {
            protected Void doInBackground() throws Exception
            {
               while (in.hasNextLine())
               {
                  String line = in.nextLine();
                  textArea.append(line);
                  textArea.append("\n");
               }
               in.close();
               return null;
            }
         };
      worker.execute();
   }

   private JMenuItem openItem;
   private JMenuItem exitItem;
   private JTextArea textArea;
   private JFileChooser chooser;

   public static final int DEFAULT_WIDTH = 300;
   public static final int DEFAULT_HEIGHT = 200;
}

   
  

Related examples in the same category