/**
* Updates the state with the given service transition.
*
* <p>This method performs the main logic of ServiceManager in the following steps.
*
* <ol>
* <li>Update the {@link #servicesByState()}
* <li>Update the {@link #startupTimers}
* <li>Based on the new state queue listeners to run
* <li>Run the listeners (outside of the lock)
* </ol>
*/
void transitionService(final Service service, State from, State to) {
checkNotNull(service);
checkArgument(from != to);
monitor.enter();
try {
transitioned = true;
if (!ready) {
return;
}
// Update state.
checkState(
servicesByState.remove(from, service),
"Service %s not at the expected location in the state map %s",
service,
from);
checkState(
servicesByState.put(to, service),
"Service %s in the state map unexpectedly at %s",
service,
to);
// Update the timer
Stopwatch stopwatch = startupTimers.get(service);
if (stopwatch == null) {
// This means the service was started by some means other than ServiceManager.startAsync
stopwatch = Stopwatch.createStarted();
startupTimers.put(service, stopwatch);
}
if (to.compareTo(RUNNING) >= 0 && stopwatch.isRunning()) {
// N.B. if we miss the STARTING event then we may never record a startup time.
stopwatch.stop();
if (!(service instanceof NoOpService)) {
logger.log(Level.FINE, "Started {0} in {1}.", new Object[] {service, stopwatch});
}
}
// Queue our listeners
// Did a service fail?
if (to == FAILED) {
fireFailedListeners(service);
}
if (states.count(RUNNING) == numberOfServices) {
// This means that the manager is currently healthy. N.B. If other threads call isHealthy
// they are not guaranteed to get 'true', because any service could fail right now.
fireHealthyListeners();
} else if (states.count(TERMINATED) + states.count(FAILED) == numberOfServices) {
fireStoppedListeners();
}
} finally {
monitor.leave();
// Run our executors outside of the lock
executeListeners();
}
}
/**
* Attempts to start the timer immediately prior to the service being started via {@link
* Service#startAsync()}.
*/
void tryStartTiming(Service service) {
monitor.enter();
try {
Stopwatch stopwatch = startupTimers.get(service);
if (stopwatch == null) {
startupTimers.put(service, Stopwatch.createStarted());
}
} finally {
monitor.leave();
}
}