Loosely based on Example1.java from http://java.sun.com/products/jfc/tsc/articles/threads/threads2.html
See also http://developer.java.sun.com/developer/qow/archive/135/index.jsp and http://jw.itworld.com/javaworld/jw-12-2000/jw-1229-traps.html @author Christopher Hylands @version $Id: JTextAreaExec.java,v 1.22 2003/05/16 23:16:54 cxh Exp $ @since Ptolemy II 2.0 */ public class JTextAreaExec extends JPanel { /** Create the JTextArea, progress bar, status text field and * optionally Start, Cancel and Clear buttons. * * @param name A String containing the name to label the JTextArea * with. * @param showButtons True if the Start, Cancel and Clear buttons * should be made visible. */ public JTextAreaExec(String name, boolean showButtons) { setLayout(new BoxLayout(this, BoxLayout.Y_AXIS)); _jTextArea = new JTextArea("", 20, 100); _jTextArea.setEditable(false); JScrollPane jScrollPane = new JScrollPane(_jTextArea); add(jScrollPane); setBorder(BorderFactory.createTitledBorder( BorderFactory.createLineBorder(Color.black), name)); _progressBar = new JProgressBar(); _startButton = new JButton("Start"); _startButton.addActionListener(_startListener); _enableStartButton(); _cancelButton = new JButton("Cancel"); _cancelButton.addActionListener(_interruptListener); _cancelButton.setEnabled(false); _clearButton = new JButton("Clear"); _clearButton.addActionListener(_clearListener); _clearButton.setEnabled(true); Border spaceBelow = BorderFactory.createEmptyBorder(0, 0, 5, 0); if (showButtons) { JComponent buttonBox = new JPanel(); buttonBox.add(_startButton); buttonBox.add(_cancelButton); buttonBox.add(_clearButton); setLayout(new BoxLayout(this, BoxLayout.Y_AXIS)); add(buttonBox); buttonBox.setBorder(spaceBelow); _statusBar = new JLabel("Click Start to begin", JLabel.CENTER); } else { _statusBar = new JLabel("", JLabel.CENTER); } add(_progressBar); add(_statusBar); _statusBar.setAlignmentX(CENTER_ALIGNMENT); Border progressBarBorder = _progressBar.getBorder(); _progressBar.setBorder(BorderFactory.createCompoundBorder( spaceBelow, progressBarBorder)); } /////////////////////////////////////////////////////////////////// //// public methods //// /** Append the text message to the JTextArea and include a trailing * newline. */ public void appendJTextArea(final String text) { Runnable doAppendJTextArea = new Runnable() { public void run() { // Oddly, we can just use '\n' here, // we do not need to call // System.getProperties("line.separator") _jTextArea.append(text + '\n'); // Scroll down as we generate text. _jTextArea.setCaretPosition(_jTextArea.getText().length()); } }; SwingUtilities.invokeLater(doAppendJTextArea); } /** Cancel any running commands. */ public void cancel() { _cancelButton.doClick(); } /** Clear the text area, status bar and progress bar. */ public void clear() { _clearButton.doClick(); updateStatusBar(""); _updateProgressBar(0); } /** Main method used for testing. * To run a simple test, use: *
* java -classpath $PTII ptolemy.gui.JTextAreaExec
*
*/
public static void main(String [] args) {
JFrame jFrame = new JFrame("JTextAreaExec Example");
WindowListener windowListener = new WindowAdapter() {
public void windowClosing(WindowEvent e) {System.exit(0);}
};
jFrame.addWindowListener(windowListener);
List execCommands = new LinkedList();
execCommands.add("date");
execCommands.add("sleep 5");
execCommands.add("date");
execCommands.add("javac");
final JTextAreaExec exec =
new JTextAreaExec("JTextAreaExec Tester", true);
exec.setCommands(execCommands);
jFrame.getContentPane().add(exec);
jFrame.pack();
jFrame.show();
SwingUtilities.invokeLater(new Runnable() {
public void run() {
//We can't do this until now
exec.getStartButton().requestFocus();
exec.start();
}
});
}
/** Return the Start button.
* This method is used to get the Start button so we can
* set the focus to it.
*/
public JButton getStartButton() {
return _startButton;
}
/** Set the list of commands. */
public void setCommands(List commands) {
_commands = commands;
_enableStartButton();
}
/** Start running the commands. */
public void start() {
_startButton.doClick();
}
/** Update the status area with the text message.*/
public void updateStatusBar(final String text) {
Runnable doUpdateStatusBar = new Runnable() {
public void run() {
_statusBar.setText(text);
_jTextArea.append(text + '\n');
}
};
SwingUtilities.invokeLater(doUpdateStatusBar);
}
///////////////////////////////////////////////////////////////////
//// private methods ////
// Enable the Start button if there are any commands in the list.
private void _enableStartButton() {
if (_commands != null && _commands.size() > 0) {
_startButton.setEnabled(true);
} else {
_startButton.setEnabled(false);
}
}
// Execute the commands in the list. Update the JTextArea with
// the command being run and the output. Update the progress bar
// and the status bar.
private Object _executeCommands() {
try {
Runtime runtime = Runtime.getRuntime();
try {
if (_process != null) _process.destroy();
_progressBar.setMaximum(_commands.size());
int commandCount = 0;
Iterator commands = _commands.iterator();
while (commands.hasNext()) {
_updateProgressBar(++commandCount);
if (Thread.interrupted()) {
throw new InterruptedException();
}
// Preprocess by removing lines that begin with '#'
// and converting substrings that begin and end
// with double quotes into one array element.
final String [] commandTokens =
StringUtilities
.tokenizeForExec((String)commands.next());
appendJTextArea("About to execute:\n");
StringBuffer statusCommand = new StringBuffer();
for (int i = 0; i < commandTokens.length; i++) {
appendJTextArea(" " + commandTokens[i]);
// Accumulate the first 50 chars for use in
// the status buffer.
if (statusCommand.length() < 50) {
if (statusCommand.length() > 0) {
statusCommand.append(" ");
}
statusCommand.append(commandTokens[i]);
}
}
if (statusCommand.length() >= 50) {
statusCommand.append(" . . .");
}
_statusBar.setText("Executing: "
+ statusCommand.toString());
_process = runtime.exec(commandTokens);
// Set up a Thread to read in any error messages
_StreamReaderThread errorGobbler = new
_StreamReaderThread(_process.getErrorStream(),
"ERROR", this);
// Set up a Thread to read in any output messages
_StreamReaderThread outputGobbler = new
_StreamReaderThread(_process.getInputStream(),
"OUTPUT", this);
// Start up the Threads
errorGobbler.start();
outputGobbler.start();
try {
int processReturnCode = _process.waitFor();
synchronized(this) {
_process = null;
}
if (processReturnCode != 0) break;
} catch (InterruptedException interrupted) {
appendJTextArea("InterruptedException: "
+ interrupted);
throw interrupted;
}
}
appendJTextArea("All Done.");
} catch (final IOException io) {
appendJTextArea("IOException: " + io);
}
}
catch (InterruptedException e) {
_process.destroy();
_updateProgressBar(0);
return "Interrupted"; // SwingWorker.get() returns this
}
return "All Done"; // or this
}
// This action listener, called by the Clear button, clears
// the text area
private ActionListener _clearListener = new ActionListener() {
public void actionPerformed(ActionEvent event) {
Runnable doAppendJTextArea = new Runnable() {
public void run() {
_jTextArea.setText(null);
}
};
SwingUtilities.invokeLater(doAppendJTextArea);
}
};
// This action listener, called by the Cancel button, interrupts
// the _worker thread which is running this._executeCommands().
// Note that the _executeCommands() method handles
// InterruptedExceptions cleanly.
private ActionListener _interruptListener = new ActionListener() {
public void actionPerformed(ActionEvent event) {
_cancelButton.setEnabled(false);
appendJTextArea("Cancel button was pressed");
_worker.interrupt();
_process.destroy();
_enableStartButton();
}
};
// This action listener, called by the Start button, effectively
// forks the thread that does the work.
private ActionListener _startListener = new ActionListener() {
public void actionPerformed(ActionEvent event) {
_startButton.setEnabled(false);
_cancelButton.setEnabled(true);
_statusBar.setText("Working...");
/* Invoking start() on the SwingWorker causes a new Thread
* to be created that will call construct(), and then
* finished(). Note that finished() is called even if
* the _worker is interrupted because we catch the
* InterruptedException in _executeCommands().
*/
_worker = new SwingWorker() {
public Object construct() {
return _executeCommands();
}
public void finished() {
_enableStartButton();
_cancelButton.setEnabled(false);
_updateProgressBar(0);
_statusBar.setText(get().toString());
}
};
_worker.start();
}
};
// When the _worker needs to update the GUI we do so by queuing a
// Runnable for the event dispatching thread with
// SwingUtilities.invokeLater(). In this case we're just changing
// the value of the progress bar.
private void _updateProgressBar(final int i) {
Runnable doSetProgressBarValue = new Runnable() {
public void run() {
//_jTextArea.append(new Integer(i).toString());
_progressBar.setValue(i);
}
};
SwingUtilities.invokeLater(doSetProgressBarValue);
}
///////////////////////////////////////////////////////////////////
//// inner classes ////
// Private class that reads a stream in a thread and updates the
// JTextArea.
private class _StreamReaderThread extends Thread {
_StreamReaderThread(InputStream inputStream, String streamType,
JTextAreaExec jTextAreaExec) {
_inputStream = inputStream;
_streamType = streamType;
_jTextAreaExec = jTextAreaExec;
}
// Read lines from the _inputStream and output them to the
// JTextArea.
public void run() {
try {
InputStreamReader inputStreamReader =
new InputStreamReader(_inputStream);
BufferedReader bufferedReader =
new BufferedReader(inputStreamReader);
String line = null;
while ( (line = bufferedReader.readLine()) != null)
_jTextAreaExec.appendJTextArea(/*_streamType + ">" +*/ line);
} catch (IOException ioe) {
_jTextAreaExec.appendJTextArea("IOException: " + ioe);
}
}
// Stream to read from.
private InputStream _inputStream;
// Description of the Stream that we print, usually "OUTPUT" or "ERROR"
private String _streamType;
// JTextArea to update
private JTextAreaExec _jTextAreaExec;
}
///////////////////////////////////////////////////////////////////
//// private variables ////
// The Cancel Button.
private JButton _cancelButton;
// The Clear Button.
private JButton _clearButton;
// The list of command to be executed. Each entry in the list is
// a String. It might be better to have each element of the list
// be an String [] so that the shell can interpret each word in
// the command.
private List _commands = null;
// JTextArea to write the command and the output of the command.
private JTextArea _jTextArea;
// The Process that we are running.
private Process _process;
// Progress bar where the length of the bar is the total number
// of commands being run.
private JProgressBar _progressBar;
// Label at the bottom that provides feedback as to what is happening.
private JLabel _statusBar;
// The Start Button.
private JButton _startButton;
// SwingWorker that actually does the work.
private SwingWorker _worker;
}