Mega Code Archive
A program to test a progress monitor input stream
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/*
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;
}
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