org.epics.ca.impl

Class JavaProcessManager

java.lang.Object

org.epics.ca.impl.JavaProcessManager

public class JavaProcessManager
extends java.lang.Object

Provides the ability to spawn JVM instances which execute a user-specified Java class with user-specified system properties and arguments.

Constructor Summary

Constructors

Constructor and Description
JavaProcessManager(java.lang.Class<?> classWithMainMethod, java.util.Properties systemProperties, java.lang.String[] programArgs) Constructs a new instance.

Method Summary

Modifier and Type	Method and Description
int	getExitValue() Returns the exit value of the process associated with this manager.
boolean	isAlive() Returns true when the process associated with this manager instance is still alive.
boolean	shutdown() Attempts to send an OS signal to kill the process associated with this class instance; WAITS for up to one second for the process to terminate; returns success indicator.
boolean	start(boolean outputCaptureEnable) Attempts to start a new JVM process based on the information supplied in the class constructor; returns success indicator.
boolean	waitFor(long timeout, java.util.concurrent.TimeUnit timeUnit) Waits for the process associated with this manager to terminate or for a timeout to occur, whichever comes soonest.

Methods inherited from class java.lang.Object

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

Constructor Detail

JavaProcessManager

public JavaProcessManager(java.lang.Class<?> classWithMainMethod,
                          java.util.Properties systemProperties,
                          java.lang.String[] programArgs)

Constructs a new instance.

Parameters:

classWithMainMethod - the Java class which contains the main method to be executed.

systemProperties - the system properties to be added to the spawned process over and above what is already provided by the platform.

programArgs - the program arguments.

Throws:

java.lang.NullPointerException - if any of the supplied arguments were null.

Method Detail

start

public boolean start(boolean outputCaptureEnable)

Attempts to start a new JVM process based on the information supplied in the class constructor; returns success indicator. This method does not block.

Parameters:

outputCaptureEnable - whether the output from the spawned process should be logged.

Returns:

indicator, set true if the startup process was successful.

shutdown

public boolean shutdown()

Attempts to send an OS signal to kill the process associated with this class instance; WAITS for up to one second for the process to terminate; returns success indicator. The process associated with this manager need not necessarily be alive when this method is invoked.

Returns:

indicator, set true if the shutdown process was successful.

isAlive

public boolean isAlive()

Returns true when the process associated with this manager instance is still alive.

Returns:

the result.

waitFor

public boolean waitFor(long timeout,
                       java.util.concurrent.TimeUnit timeUnit)
                throws java.lang.InterruptedException

Waits for the process associated with this manager to terminate or for a timeout to occur, whichever comes soonest.

Parameters:

timeout - the maximum time to wait.

timeUnit - the time units.

Returns:

true indicates the process has terminated; false indicates a timeout occurred.

Throws:

java.lang.InterruptedException - if the current thread was interrupted while waiting.

getExitValue

public int getExitValue()

Returns the exit value of the process associated with this manager. This method should only be called after the process has terminated.

Returns:

the exit value.

Throws:

java.lang.IllegalThreadStateException - - if the process has not yet terminated.