org.activemath.presentation.io
Class ExecStream

java.lang.Object
  java.io.OutputStream
      org.activemath.presentation.io.ExecStream

All Implemented Interfaces:

Closeable, Flushable

public class ExecStream
extends OutputStream

Encapsulate an external process into an OutputStream. Execution begins as soon as any data is written to the stream, or when the stream is closed.
Typical usage is as follows:

  public static void main(String [] args) {
    ExecStream execStream;
    execStream = new ExecStream();

    try {
      String [] command = { "maxima" };
      String input = "2+3=4;";
      execStream.setCommand(command);
      execStream.write(input.getBytes("UTF-8"));
      execStream.close();
    } catch (IOException e) {
      System.err.println(e.getMessage());
    }
  }
 

In this example, since no output stream is given, the output is sent to "System.out". Same for the error stream, whose default is "System.err".

Version:

$Revision: 1.10 $ $Date: 2007/08/07 13:11:33 $

Field Summary

protected static Logger

log

Constructor Summary

ExecStream()

ExecStream(OutputStream out)

ExecStream(OutputStream out, String[] command, File workingDirectory, OutputStream err, long timeout)

ExecStream(OutputStream out, String[] command, OutputStream err, long timeout)

Method Summary

void	close()
protected void	finalize()
void	flush()
int	getExitValue()
void	killProcess()
static void	main(String[] args) For testing.
void	setCommand(String[] command)
void	setErrorStream(OutputStream err) Error stream for the process.
void	setOutputStream(OutputStream out)
void	setTimeout(long timeout) Process timeout.
void	setWorkingDirectory(File workingDirectory)
void	write(byte[] b)
void	write(byte[] b, int offset, int len)
void	write(int b)

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

log

protected static Logger log

Constructor Detail

ExecStream

public ExecStream()

ExecStream

public ExecStream(OutputStream out)

ExecStream

public ExecStream(OutputStream out,
                  String[] command,
                  OutputStream err,
                  long timeout)

ExecStream

public ExecStream(OutputStream out,
                  String[] command,
                  File workingDirectory,
                  OutputStream err,
                  long timeout)

Method Detail

killProcess

public void killProcess()

finalize

protected final void finalize()
                       throws Throwable

Overrides:

finalize in class Object

Throws:

Throwable

setCommand

public void setCommand(String[] command)

setWorkingDirectory

public void setWorkingDirectory(File workingDirectory)

setOutputStream

public void setOutputStream(OutputStream out)

setErrorStream

public void setErrorStream(OutputStream err)

Error stream for the process.

Parameters:

err - stream to receive errors. Default is "System.err".

setTimeout

public void setTimeout(long timeout)

Process timeout.
If the process takes more than timeout milliseconds to execute, it's aborted.
A value of 0 means that the process should not be interrupted.

Parameters:

timeout - maximum allowed time for the process to finish.

getExitValue

public int getExitValue()

Returns:

exitValue of terminated process, or -1.

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Overrides:

flush in class OutputStream

Throws:

IOException

write

public void write(int b)
           throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] b)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

write

public void write(byte[] b,
                  int offset,
                  int len)
           throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

close

public void close()
           throws IOException

Specified by:

close in interface Closeable

Overrides:

close in class OutputStream

Throws:

IOException

main

public static void main(String[] args)

For testing. This sends a string to an external process, and redirects its output to the Java runtime's standard output.