net.fenyo.gnetwatch.actions
Class ExternalCommand

java.lang.Object
  net.fenyo.gnetwatch.actions.ExternalCommand

public class ExternalCommand
extends java.lang.Object

Instances of this class launch and manage processes outside of the JVM.

Version:

$Id: ExternalCommand.java,v 1.17 2008/05/22 19:46:21 fenyo Exp $

Author:

Alexandre Fenyo

Field Summary

private java.lang.String[]	cmdLine
private java.lang.String	directory
private java.io.BufferedReader	errReader
private static Log	log
private boolean	merge
private java.lang.Process	process
private java.io.BufferedReader	reader
private java.lang.StringBuffer	sb

Constructor Summary

ExternalCommand(java.lang.String[] cmdLine)
Creates an ExternalCommand instance and saves the command line.

ExternalCommand(java.lang.String[] cmdLine, boolean merge)
Creates an ExternalCommand instance and saves the command line.

ExternalCommand(java.lang.String[] cmdLine, boolean merge, java.lang.String curdir)

ExternalCommand(java.lang.String[] cmdLine, java.lang.String directory)
Creates an ExternalCommand instance and saves the command line.

Method Summary

void	end() Make sure the underlying file descriptors are closed, to avoid maintening unused resources in an application server JVM for instance.
void	fork() Launches a process but do not wait for its completion.
private void	kill() Kills the process.
void	logArgs() Displays command line arguments.
private java.lang.String	readLine(java.io.Reader r) Reads a line from the process output.
java.lang.String	readLineStderr() Reads one line of the stderr.
java.lang.String	readLineStdout() Reads one line of the stdout.
java.lang.String	readStderr() Reads stderr.
java.lang.String	readStdout() Reads stdout.
java.lang.String	readStdoutStderr() Merges stdout and stderr.
java.lang.String	runStdout() Reads the whole standard output.
java.lang.String	runStdoutStderr() Reads the whole output.

Methods inherited from class java.lang.Object

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

Field Detail

log

private static Log log

merge

private boolean merge

cmdLine

private final java.lang.String[] cmdLine

directory

private final java.lang.String directory

sb

private final java.lang.StringBuffer sb

process

private java.lang.Process process

reader

private java.io.BufferedReader reader

errReader

private java.io.BufferedReader errReader

Constructor Detail

ExternalCommand

public ExternalCommand(java.lang.String[] cmdLine,
                       java.lang.String directory)

Creates an ExternalCommand instance and saves the command line. any thread.

Parameters:

cmdLine - command line.

directory - path to the current directory for the script to be launched.

ExternalCommand

public ExternalCommand(java.lang.String[] cmdLine)

Creates an ExternalCommand instance and saves the command line. any thread.

Parameters:

cmdLine - command line.

ExternalCommand

public ExternalCommand(java.lang.String[] cmdLine,
                       boolean merge)

Creates an ExternalCommand instance and saves the command line. any thread.

Parameters:

cmdLine - command line.

merge - merge standard output and standard error.

ExternalCommand

public ExternalCommand(java.lang.String[] cmdLine,
                       boolean merge,
                       java.lang.String curdir)

Method Detail

readLine

private java.lang.String readLine(java.io.Reader r)
                           throws java.io.IOException,
                                  java.lang.InterruptedException

Reads a line from the process output.

Parameters:

r - reader.

Returns:

line read.

Throws:

java.io.IOException - IO exception.

java.lang.InterruptedException - exception.

runStdoutStderr

public java.lang.String runStdoutStderr()
                                 throws java.lang.InterruptedException

Reads the whole output.

Returns:

whole output.

Throws:

java.lang.InterruptedException - exception.

runStdout

public java.lang.String runStdout()
                           throws java.lang.InterruptedException

Reads the whole standard output.

Returns:

whole standard output.

Throws:

java.lang.InterruptedException - interrupted.

logArgs

public void logArgs()

Displays command line arguments. any thread.

Parameters:

none. -

fork

public void fork()
          throws java.io.IOException

Launches a process but do not wait for its completion. any thread.

Parameters:

none. -

Throws:

java.io.IOException - i/o exception before reading the process output stream.

readStdoutStderr

public java.lang.String readStdoutStderr()
                                  throws java.io.IOException,
                                         java.lang.InterruptedException

Merges stdout and stderr. Waits for the end of the process output stream. Note that this method can return before the process completion. any thread.

Parameters:

none. -

Returns:

void.

Throws:

java.io.IOException - i/o exception while reading the process output stream.

java.lang.InterruptedException

readStdout

public java.lang.String readStdout()
                            throws java.io.IOException,
                                   java.lang.InterruptedException

Reads stdout. Waits for the end of the process output stream. Note that this method can return before the process completion. any thread.

Parameters:

none. -

Returns:

void.

Throws:

java.io.IOException - i/o exception while reading the process output stream.

java.lang.InterruptedException

readStderr

public java.lang.String readStderr()
                            throws java.io.IOException,
                                   java.lang.InterruptedException

Reads stderr. Waits for the closure of the process output stream. Note that this method can return before the process completion. any thread.

Parameters:

none. -

Returns:

void.

Throws:

java.io.IOException - i/o exception while reading the process output stream.

java.lang.InterruptedException

readLineStdout

public java.lang.String readLineStdout()
                                throws java.io.IOException,
                                       java.lang.InterruptedException

Reads one line of the stdout. any thread.

Parameters:

none. -

Returns:

void.

Throws:

java.io.IOException - i/o exception while reading the process output stream.

java.lang.InterruptedException

readLineStderr

public java.lang.String readLineStderr()
                                throws java.io.IOException,
                                       java.lang.InterruptedException

Reads one line of the stderr. any thread.

Parameters:

none. -

Returns:

void.

Throws:

java.io.IOException - i/o exception while reading the process output stream.

java.lang.InterruptedException

end

public void end()
         throws java.io.IOException

Make sure the underlying file descriptors are closed, to avoid maintening unused resources in an application server JVM for instance. any thread.

Parameters:

none. -

Throws:

java.io.IOException - error while closing streams.

kill

private void kill()

Kills the process. We do not reset process to null since it can be used to get exit code. any thread.

Parameters:

none. -