edu.rice.cs.util
Class ProcessSequence

java.lang.Object
  java.lang.Process
      edu.rice.cs.util.ProcessSequence

public class ProcessSequence
extends Process

This class represents a sequence of processes. The inputs and outputs of the processes are not connected. One process wait until the preceding process has terminated. The class allows the entire sequence to be treated as if it were just one process. The constructor starts the first subprocess.

Nested Class Summary

protected class

ProcessSequence.ProcessSequenceThreadGroup Thread group for all threads that deal with this process sequence.

Field Summary

protected boolean	_aborted True if the execution was aborted.
protected PipedInputStream	_combinedErrorStream The combined error stream of all processes.
protected JoinInputStream	_combinedInputJoinedWithDebugStream The combined input stream of all the processes, plus a debug stream.
protected PipedInputStream	_combinedInputStream The combined input stream of all processes.
protected OutputStream	_combinedOutputStream The output stream of the currently executing process.
protected PipedOutputStream	_combinedStdErrStream The stream into which all outputs to stderr are written.
protected PipedOutputStream	_combinedStdOutStream The stream into which all outputs to stdout are written.
protected ProcessCreator[]	_creators The process creators that create the processes in this process sequence.
protected Thread	_deathThread Thread that monitors the subprocesses and starts the next process when the previous one has terminated.
protected PipedInputStream	_debugInputStream Debug input and output stream.
protected PrintWriter	_debugOutput Debug output that gets joined with the streams from the processes.
protected PipedOutputStream	_debugOutputStream
protected int	_index Index of the currently running process.
protected Process[]	_processes The processes inside this process sequence.
protected StreamRedirectThread	_stdErrRedirector The redirector thread that moves stderr output from one process to the input of the next process.
protected StreamRedirectThread	_stdOutRedirector The redirector thread that moves stdout output from one process to the input of the next process.
protected static Process	DUMMY_PROCESS A process that does nothing.

Constructor Summary

ProcessSequence(ProcessCreator[] pcs)
Constructor for a process sequence consisting of the individual processes provided.

Method Summary

protected void	connectProcess(Process p) Connect the streams of the specified process.
void	destroy() Kills all subprocesses.
int	exitValue() Returns the exit value for the subprocess.
InputStream	getErrorStream() Gets the error stream of the process sequence, i.e.
InputStream	getInputStream() Gets the input stream of the process sequence, i.e.
OutputStream	getOutputStream() Gets the output stream of the process sequence, i.e.
protected void	stopAllRedirectors() Set the stop flags for all redirector threads.
int	waitFor() Causes the current thread to wait, if necessary, until the process sequence has terminated, i.e.

Methods inherited from class java.lang.Object

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

Field Detail

_creators

protected ProcessCreator[] _creators

The process creators that create the processes in this process sequence.

_processes

protected Process[] _processes

The processes inside this process sequence.

_index

protected volatile int _index

Index of the currently running process.

_aborted

protected volatile boolean _aborted

True if the execution was aborted.

_stdOutRedirector

protected StreamRedirectThread _stdOutRedirector

The redirector thread that moves stdout output from one process to the input of the next process.

_stdErrRedirector

protected StreamRedirectThread _stdErrRedirector

The redirector thread that moves stderr output from one process to the input of the next process.

_combinedInputStream

protected PipedInputStream _combinedInputStream

The combined input stream of all processes.

_combinedStdOutStream

protected PipedOutputStream _combinedStdOutStream

The stream into which all outputs to stdout are written.

_combinedInputJoinedWithDebugStream

protected JoinInputStream _combinedInputJoinedWithDebugStream

The combined input stream of all the processes, plus a debug stream.

_debugOutput

protected PrintWriter _debugOutput

Debug output that gets joined with the streams from the processes.

_debugInputStream

protected PipedInputStream _debugInputStream

Debug input and output stream.

_debugOutputStream

protected PipedOutputStream _debugOutputStream

_combinedErrorStream

protected PipedInputStream _combinedErrorStream

The combined error stream of all processes.

_combinedStdErrStream

protected PipedOutputStream _combinedStdErrStream

The stream into which all outputs to stderr are written.

_combinedOutputStream

protected volatile OutputStream _combinedOutputStream

The output stream of the currently executing process.

_deathThread

protected Thread _deathThread

Thread that monitors the subprocesses and starts the next process when the previous one has terminated.

DUMMY_PROCESS

protected static final Process DUMMY_PROCESS

A process that does nothing.

Constructor Detail

ProcessSequence

public ProcessSequence(ProcessCreator[] pcs)

Constructor for a process sequence consisting of the individual processes provided.

Parameters:

pcs - array of ProcessCreators

Method Detail

getOutputStream

public OutputStream getOutputStream()

Gets the output stream of the process sequence, i.e. the combined output stream of all the processes in the sequence.

Specified by:

getOutputStream in class Process

Returns:

the output stream of the process sequence.

getErrorStream

public InputStream getErrorStream()

Gets the error stream of the process sequence, i.e. the combined error stream of all the processes in the sequence.

Specified by:

getErrorStream in class Process

Returns:

the error stream of the process sequence.

getInputStream

public InputStream getInputStream()

Gets the input stream of the process sequence, i.e. the combined input stream of all the processes in the sequence.

Specified by:

getInputStream in class Process

Returns:

the input stream of the process chain

waitFor

public int waitFor()
            throws InterruptedException

Causes the current thread to wait, if necessary, until the process sequence has terminated, i.e. until all processes in the sequence have terminated. This method returns immediately if all subprocesses have already terminated. If any of the subprocess has not yet terminated, the calling thread will be blocked until all subprocesses exit.

Specified by:

waitFor in class Process

Returns:

the exit value of the process chain, i.e. the exit code of the last process in the sequence.

Throws:

InterruptedException - if the current thread is interrupted by another thread while it is waiting, then the wait is ended and an InterruptedException is thrown.

exitValue

public int exitValue()

Returns the exit value for the subprocess.

Specified by:

exitValue in class Process

Returns:

the exit value of the subprocess represented by this Process object. by convention, the value 0 indicates normal termination.

Throws:

IllegalThreadStateException - if the subprocess represented by this Process object has not yet terminated.

destroy

public void destroy()

Kills all subprocesses. The subprocesses represented by this ProcessChain object is forcibly terminated.

Specified by:

destroy in class Process

stopAllRedirectors

protected void stopAllRedirectors()

Set the stop flags for all redirector threads.

connectProcess

protected void connectProcess(Process p)

Connect the streams of the specified process.