gate.util

Class ProcessManager

java.lang.Object

gate.util.ProcessManager

public class ProcessManager
extends Object

Class that supports running an external process and either silently consuming its standard output and error streams, or copying them to Java's stdout and stderr. This implementation reads the output and error streams in separate threads, but tries to reuse these threads from one external call to the next, unlike other approaches I've seen (which all spawn a pair of new threads for every external call). As a result, instances of this class are not thread safe. You must use a different instance of ProcessManager in each thread that you use to run external processes.

Constructor Summary

Constructors

Constructor and Description
ProcessManager() Construct a ProcessManager object and start the gobbler threads.

Method Summary

Modifier and Type	Method and Description
void	destroyProcess() If a process is currently running then this method destroys it so that the ProcessManager instance can be used to start another process
boolean	isProcessRunning()
int	runProcess(String[] argv, boolean dumpOutput) Run the given external process.
int	runProcess(String[] argv, File dir, OutputStream out, OutputStream err) Run the given external process.
int	runProcess(String[] argv, OutputStream out, OutputStream err)
OutputStream	startProcess(String[] argv, File dir, OutputStream out, OutputStream err) Sometimes you want to start an external process and pass data to it at different intervals.

Methods inherited from class java.lang.Object

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

Constructor Detail

ProcessManager

public ProcessManager()

Construct a ProcessManager object and start the gobbler threads.

Method Detail

isProcessRunning

public boolean isProcessRunning()

destroyProcess

public void destroyProcess()
                    throws IOException

If a process is currently running then this method destroys it so that the ProcessManager instance can be used to start another process

Throws:

IOException

startProcess

public OutputStream startProcess(String[] argv,
                                 File dir,
                                 OutputStream out,
                                 OutputStream err)
                          throws IOException

Sometimes you want to start an external process and pass data to it at different intervals. A good example is a tool with large startup time where you can feed it one sentence at a time and get a response. If you keep the process running you can use it over multiple documents.

Throws:

IOException

runProcess

public int runProcess(String[] argv,
                      boolean dumpOutput)
               throws IOException

Run the given external process. If an exception results from starting the process, or while reading the output from the process, it will be thrown. Otherwise, the exit value from the process is returned.

Parameters:

argv - the process command line, suitable for passing to Runtime.exec.

dumpOutput - should we copy the process output and error streams to the Java output and error streams or just consume them silently?

Throws:

IOException

runProcess

public int runProcess(String[] argv,
                      OutputStream out,
                      OutputStream err)
               throws IOException

Throws:

IOException

runProcess

public int runProcess(String[] argv,
                      File dir,
                      OutputStream out,
                      OutputStream err)
               throws IOException

Run the given external process. If an exception results from starting the process, or while reading the output from the process, it will be thrown. Otherwise, the exit value from the process is returned.

Parameters:

argv - the process command line, suitable for passing to Runtime.exec.

Throws:

IOException