12 JULY

DOWNLOAD MANAGER CLASS
import java.awt.*;
import java.awt.event.*;
import java.net.*;
import java.util.*;
import javax.swing.*;
import javax.swing.event.*;

public class DownloadManager extends JFrame
implements Observer
{

private JTextField addTextField;

private DownloadsTableModel tableModel;

private JTable table;

private JButton pauseButton, resumeButton;
private JButton cancelButton, clearButton;

private Download selectedDownload;

private boolean clearing;

public DownloadManager()
{

setTitle("IDM");

setSize(640, 480);

addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
 {
actionExit();
}
});

// add panel.
JPanel addPanel = new JPanel();
addPanel.setBackground(Color.darkGray);
addTextField = new JTextField(30);
Font font = new Font("Arial Narrow",Font.ITALIC,22);
addTextField.setFont(font);
addPanel.add(addTextField);
JButton addButton = new JButton();
ImageIcon img = new ImageIcon("C:\\j\\demo\\add.png");
addButton.setIcon(img);
addButton.setBorder(BorderFactory.createEmptyBorder());
addButton.setContentAreaFilled(false);
addButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionAdd();
}
});
addPanel.add(addButton);

//Downloads table.
tableModel = new DownloadsTableModel();
table = new JTable(tableModel);
table.getSelectionModel().addListSelectionListener(new
ListSelectionListener() {
public void valueChanged(ListSelectionEvent e) {
tableSelectionChanged();
}
});

table.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);

ProgressRenderer renderer = new ProgressRenderer(0, 100);
renderer.setStringPainted(true);
table.setDefaultRenderer(JProgressBar.class, renderer);

table.setRowHeight(
(int) renderer.getPreferredSize().getHeight());
//download panel
JPanel downloadsPanel = new JPanel();
downloadsPanel.setBackground(Color.lightGray);
downloadsPanel.setBorder(
BorderFactory.createTitledBorder("Downloads Area"));
downloadsPanel.setLayout(new BorderLayout());
downloadsPanel.add(new JScrollPane(table),
BorderLayout.CENTER);

// buttons panel.
JPanel buttonsPanel = new JPanel();
buttonsPanel.setBackground(Color.darkGray);
pauseButton = new JButton();
ImageIcon img1 = new ImageIcon("C:\\j\\demo\\pause.png");
pauseButton.setIcon(img1);
pauseButton.setBorder(BorderFactory.createEmptyBorder());
pauseButton.setContentAreaFilled(false);
pauseButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionPause();
}
});
pauseButton.setEnabled(false);
buttonsPanel.add(pauseButton);
resumeButton = new JButton();
ImageIcon img2 = new ImageIcon("C:\\j\\demo\\play.png");
resumeButton.setIcon(img2);
resumeButton.setBorder(BorderFactory.createEmptyBorder());
resumeButton.setContentAreaFilled(false);
resumeButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionResume();
}
});
resumeButton.setEnabled(false);
buttonsPanel.add(resumeButton);
cancelButton = new JButton();
ImageIcon img3 = new ImageIcon("C:\\j\\demo\\cancel.png");
cancelButton.setIcon(img3);
cancelButton.setBorder(BorderFactory.createEmptyBorder());
cancelButton.setContentAreaFilled(false);
cancelButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionCancel();
}
});
cancelButton.setEnabled(false);
buttonsPanel.add(cancelButton);
clearButton = new JButton();
ImageIcon img4 = new ImageIcon("C:\\j\\demo\\clear.png");
clearButton.setIcon(img4);
clearButton.setBorder(BorderFactory.createEmptyBorder());
clearButton.setContentAreaFilled(false);
clearButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
actionClear();
}
});
clearButton.setEnabled(false);
buttonsPanel.add(clearButton);
// add panels
getContentPane().setLayout(new BorderLayout());
getContentPane().add(addPanel, BorderLayout.NORTH);
getContentPane().add(downloadsPanel, BorderLayout.CENTER);
getContentPane().add(buttonsPanel, BorderLayout.SOUTH);
}

private void actionExit() {
System.exit(0);
}
// add new download.
private void actionAdd() {
URL verifiedUrl = verifyUrl(addTextField.getText());
if (verifiedUrl != null) {
tableModel.addDownload(new Download(verifiedUrl));
addTextField.setText("");
} else {
JOptionPane.showMessageDialog(this,
"Invalid Download URL", "Error",
JOptionPane.ERROR_MESSAGE);
}
}

private URL verifyUrl(String url) {

if (!url.toLowerCase().startsWith("http://"))
return null;

URL verifiedUrl = null;
try {
verifiedUrl = new URL(url);
} catch (Exception e) {
return null;
}

if (verifiedUrl.getFile().length() < 2)
return null;
return verifiedUrl;
}

private void tableSelectionChanged() {

if (selectedDownload != null)
selectedDownload.deleteObserver(DownloadManager.this);

if (!clearing && table.getSelectedRow() > -1) {
selectedDownload =
tableModel.getDownload(table.getSelectedRow());
selectedDownload.addObserver(DownloadManager.this);
updateButtons();
}
}

private void actionPause() {
selectedDownload.pause();
updateButtons();
}

private void actionResume() {
selectedDownload.resume();
updateButtons();
}

private void actionCancel() {
selectedDownload.cancel();
updateButtons();
}

private void actionClear() {
clearing = true;
tableModel.clearDownload(table.getSelectedRow());
clearing = false;
selectedDownload = null;
updateButtons();
}

private void updateButtons() {
if (selectedDownload != null) {
int status = selectedDownload.getStatus();
switch (status) {
case Download.DOWNLOADING:
pauseButton.setEnabled(true);
resumeButton.setEnabled(false);
cancelButton.setEnabled(true);
clearButton.setEnabled(false);
break;
case Download.PAUSED:
pauseButton.setEnabled(false);
resumeButton.setEnabled(true);
cancelButton.setEnabled(true);
clearButton.setEnabled(false);
break;
case Download.ERROR:
pauseButton.setEnabled(false);
resumeButton.setEnabled(true);
cancelButton.setEnabled(false);
clearButton.setEnabled(true);
break;
default:
pauseButton.setEnabled(false);
resumeButton.setEnabled(false);
cancelButton.setEnabled(false);
clearButton.setEnabled(true);
}
} else {

pauseButton.setEnabled(false);
resumeButton.setEnabled(false);
cancelButton.setEnabled(false);
clearButton.setEnabled(false);
}
}

public void update(Observable o, Object arg) {

if (selectedDownload != null && selectedDownload.equals(o))
updateButtons();
}

public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
DownloadManager manager = new DownloadManager();
manager.setVisible(true);
}
});
}
}