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 @see JTextAreaExec @author Christopher Hylands @version $Id: StreamExec.java,v 1.7 2003/05/16 23:16:54 cxh Exp $ @since Ptolemy II 2.0 */ public class StreamExec { /** Create a StreamExec */ public StreamExec() { // Does nothing? } /////////////////////////////////////////////////////////////////// //// public methods //// /** Cancel any running commands. */ public void cancel() { //_worker.interrupt(); _process.destroy(); } /** Clear the text area, status bar and progress bar. */ public void clear() { updateStatusBar(""); _updateProgressBar(0); } /** Return the value of the Process. Typically the return value * of this method is used to have the caller wait for the process * to exit. */ public Process getProcess() { return _process; } /** Main method used for testing. * To run a simple test, use: *
* java -classpath $PTII ptolemy.gui.StreamExec
*
*/
public static void main(String [] args) {
List execCommands = new LinkedList();
execCommands.add("date");
execCommands.add("sleep 5");
execCommands.add("date");
execCommands.add("javac");
final StreamExec exec =
new StreamExec();
exec.setCommands(execCommands);
exec.start();
}
/** Set the list of commands. */
public void setCommands(List commands) {
_commands = commands;
}
/** Start running the commands. */
public void start() {
String returnValue = _executeCommands();
updateStatusBar(returnValue);
stdout(returnValue);
}
/** Append the text message to stderr. A derived class could
* append to a StringBuffer. @link{JTextAreaExec} appends to a
* JTextArea. The output automatically gets a trailing newline
* appended.
*/
public void stderr(final String text) {
System.err.println(text);
System.err.flush();
}
/** Append the text message to the output. A derived class could
* append to a StringBuffer. @link{JTextAreaExec} appends to a
* JTextArea.
* The output automatically gets a trailing newline appended.
*/
public void stdout(final String text) {
System.out.println(text);
System.out.flush();
}
/** Set the text of the status bar. In this base class, do
* nothing, derived classes may update a status bar.
*/
public void updateStatusBar(final String text) {
}
///////////////////////////////////////////////////////////////////
//// protected methods ////
/** Set the maximum of the progress bar. In this base class, do
* nothing, derived classes may update the size of the progress bar.
* @param size The maximum size of the progress bar.
*/
protected void _setProgressBarMaximum(int size) {
}
/** Update the progress bar. In this base class, do nothing.
* @i The current location of the progress bar.
*/
private void _updateProgressBar(final int i) {
}
///////////////////////////////////////////////////////////////////
//// private methods ////
// Execute the commands in the list. Update the output with
// the command being run and the output.
private String _executeCommands() {
try {
Runtime runtime = Runtime.getRuntime();
try {
if (_process != null){
_process.destroy();
}
_setProgressBarMaximum(_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());
stdout("About to execute:\n");
StringBuffer statusCommand = new StringBuffer();
for (int i = 0; i < commandTokens.length; i++) {
stdout(" " + 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(" . . .");
}
updateStatusBar("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) {
stderr("InterruptedException: "
+ interrupted);
throw interrupted;
}
}
} catch (final IOException io) {
stderr("IOException: " + io);
}
}
catch (InterruptedException e) {
_process.destroy();
_updateProgressBar(0);
return "Interrupted"; // SwingWorker.get() returns this
}
return "All Done"; // or this
}
///////////////////////////////////////////////////////////////////
//// 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,
StreamExec streamExec) {
_inputStream = inputStream;
_streamType = streamType;
_streamExec = streamExec;
}
// Read lines from the _inputStream and output them.
public void run() {
try {
InputStreamReader inputStreamReader =
new InputStreamReader(_inputStream);
BufferedReader bufferedReader =
new BufferedReader(inputStreamReader);
String line = null;
while ( (line = bufferedReader.readLine()) != null) {
_streamExec.stdout(/*_streamType + ">" +*/ line);
}
} catch (IOException ioe) {
_streamExec.stderr("IOException: " + ioe);
}
}
// Stream to read from.
private InputStream _inputStream;
// Description of the Stream that we print, usually "OUTPUT" or "ERROR"
private String _streamType;
private StreamExec _streamExec;
}
///////////////////////////////////////////////////////////////////
//// private variables ////
// 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;
// The Process that we are running.
private Process _process;
// SwingWorker that actually does the work.
//private SwingWorker _worker;
}