org.janusgraph

Class DaemonRunner<S>

java.lang.Object

org.janusgraph.DaemonRunner<S>

public abstract class DaemonRunner<S>
extends Object

Constructor Summary

Constructors

Constructor and Description
DaemonRunner()

Method Summary

Modifier and Type	Method and Description
protected abstract String	getDaemonShortName()
protected abstract void	killImpl(S stat)
protected abstract S	readStatusFromDisk()
static void	runCommand(String... argv) Run the parameter as an external process.
S	start() Read daemon status from disk, then try to start the daemon if the status file says it is stopped.
protected abstract S	startImpl()
void	stop() Read daemon status from disk, then try to kill the daemon if the status file says it is running.

Methods inherited from class java.lang.Object

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

Constructor Detail

DaemonRunner

public DaemonRunner()

Method Detail

getDaemonShortName

protected abstract String getDaemonShortName()

killImpl

protected abstract void killImpl(S stat)
                          throws IOException

Throws:

IOException

startImpl

protected abstract S startImpl()
                        throws IOException

Throws:

IOException

readStatusFromDisk

protected abstract S readStatusFromDisk()

start

public S start()

Read daemon status from disk, then try to start the daemon if the status file says it is stopped. Do nothing if the status read from disk says the daemon is running. After successfully starting the daemon (no exceptions from startImpl(), register a shutdown hook with the VM that will call killImpl(S) on shutdown.

Returns:

status representing the daemon, either just-started or already running

stop

public void stop()

Read daemon status from disk, then try to kill the daemon if the status file says it is running. Do nothing if the status read from disk says the daemon is stopped.

runCommand

public static void runCommand(String... argv)

Run the parameter as an external process. Returns if the command starts without throwing an exception and returns exit status 0. Throws an exception if there's any problem invoking the command or if it does not return zero exit status. Blocks indefinitely while waiting for the command to complete.

Parameters:

argv - passed directly to ProcessBuilder's constructor