alma::acs::util::ProcessStreamGobbler Class Reference

Collaboration diagram for alma::acs::util::ProcessStreamGobbler:

Classes
class	GobblerRunnable
Public Member Functions
	ProcessStreamGobbler (Process proc, ThreadFactory tf, boolean storeStreamContent)
void	gobbleAsync () throws InterruptedException
boolean	gobble (long timeout, TimeUnit unit) throws InterruptedException
List< String >	getStdout ()
List< String >	getStderr ()
boolean	hasStreamReadErrors ()
boolean	hasTerminated ()
void	setDebug (boolean DEBUG)
Private Attributes
final Process	proc
final List< String >	stdout
final List< String >	stderr
final ThreadFactory	tf
GobblerRunnable	runErr
GobblerRunnable	runOut
volatile boolean	DEBUG = false

Detailed Description

Continuously reads the stdout and stderr streams of Process in separate threads, so that the OS will not block out the JVM, as it could otherwise happen if lines are read from these streams sequentially in one thread.

This class is only useful if the external process's output is either not interesting at all for the user, or if the output should be read only after the process has terminated. Otherwise the streams should be read directly without using this class.

The gobble(long, TimeUnit) call returns either when both stdout and stderr streams deliver a null, or if the timeout is reached. check if relying on the null from both streams is as robust as Process#waitFor().

Author:: hsommer

Constructor & Destructor Documentation

alma::acs::util::ProcessStreamGobbler::ProcessStreamGobbler	(	Process	proc,
		ThreadFactory	tf,
		boolean	storeStreamContent
	)			`[inline]`

Parameters:

	proc	The process whose streams we want to read.
	tf	ThreadFactory to be used to create the two threads that read the stdout and stderr streams
	storeStreamContent	If true, then the stdout and stderr content will be stored and can be read using getStdout() and getStderr() : set max sizes for the buffers

References stderr, and stdout.

Member Function Documentation

List<String> alma::acs::util::ProcessStreamGobbler::getStderr ( ) [inline]

Returns the stderr data read, or null if storeStreamContent==false

References stderr.

Referenced by alma::acs::testsupport::ProcessUtilTest::testJava().

List<String> alma::acs::util::ProcessStreamGobbler::getStdout ( ) [inline]

Returns the stdout data read, or null if storeStreamContent==false

References stdout.

Referenced by alma::acs::testsupport::ProcessUtil::getJavaPIDs(), and alma::acs::testsupport::ProcessUtilTest::testJava().

boolean alma::acs::util::ProcessStreamGobbler::gobble	(	long	timeout,
		TimeUnit	unit
	)			throws InterruptedException `[inline]`

Starts fetching process output from stdout/stderr, storing it internally so that it can later be read via getStdout() and getStderr().

Use this method if you want to wait for the process to end, limited by a timeout.

: set max sizes for the buffers

Parameters:

	timeout	maximum time to wait for the process to finish
	unit	unit for the timeout

Returns:: true if returning because the process ended, otherwise false if the timeout applied (in which case the streams will continue to be read though).

Exceptions:

InterruptedException

References DEBUG, proc, runErr, runOut, stderr, stdout, and tf.

Referenced by alma::acs::testsupport::ProcessUtil::getJavaPIDs(), gobbleAsync(), and alma::acs::testsupport::ProcessUtilTest::testJava().

void alma::acs::util::ProcessStreamGobbler::gobbleAsync ( ) throws InterruptedException [inline]

Starts fetching process output from stdout/stderr, storing it internally so that it can later be read via getStdout() and getStderr().

Use this method if you do not want to wait for the process to end. The status can anyway be checked using hasTerminated().

Parameters:

	timeout	maximum time to wait for the process to finish
	unit	unit for the timeout

Returns:: true if returning because the process ended, otherwise false if the timeout applied (in which case the streams will continue to be read though).

Exceptions:

InterruptedException

References gobble().

boolean alma::acs::util::ProcessStreamGobbler::hasStreamReadErrors ( ) [inline]