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java.lang.Objectcom.google.common.util.concurrent.AbstractIdleService
@Beta public abstract class AbstractIdleService
Base class for services that do not need a thread while "running"
but may need one during startup and shutdown. Subclasses can
implement startUp() and shutDown() methods, each
which run in a executor which by default uses a separate thread
for each method.
| Nested Class Summary |
|---|
| Nested classes/interfaces inherited from interface com.google.common.util.concurrent.Service |
|---|
Service.Listener, Service.State |
| Constructor Summary | |
|---|---|
AbstractIdleService()
|
|
| Method Summary | |
|---|---|
void |
addListener(Service.Listener listener,
Executor executor)
Registers a Service.Listener to be executed on the given
executor. |
protected Executor |
executor(Service.State state)
Returns the Executor that will be used to run this service. |
boolean |
isRunning()
Returns true if this service is running. |
protected abstract void |
shutDown()
Stop the service. |
ListenableFuture<Service.State> |
start()
If the service state is Service.State.NEW, this initiates service startup and returns
immediately. |
Service.State |
startAndWait()
Initiates service startup (if necessary), returning once the service has finished starting. |
protected abstract void |
startUp()
Start the service. |
Service.State |
state()
Returns the lifecycle state of the service. |
ListenableFuture<Service.State> |
stop()
If the service is starting or running, this initiates service shutdown and returns immediately. |
Service.State |
stopAndWait()
Initiates service shutdown (if necessary), returning once the service has finished stopping. |
String |
toString()
|
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
| Constructor Detail |
|---|
public AbstractIdleService()
| Method Detail |
|---|
protected abstract void startUp()
throws Exception
Exception
protected abstract void shutDown()
throws Exception
Exceptionprotected Executor executor(Service.State state)
Executor that will be used to run this service.
Subclasses may override this method to use a custom Executor, which
may configure its worker thread with a specific name, thread group or
priority. The returned executor's execute() method is called when this service is started and stopped,
and should return promptly.
state - Service.State.STARTING or
Service.State.STOPPING, used by the default implementation for
naming the threadpublic String toString()
toString in class Objectpublic final ListenableFuture<Service.State> start()
ServiceService.State.NEW, this initiates service startup and returns
immediately. If the service has already been started, this method returns immediately without
taking action. A stopped service may not be restarted.
start in interface ServiceFuture.get() will block until the service has finished
starting, and returns one of Service.State.RUNNING, Service.State.STOPPING or
Service.State.TERMINATED. If the service fails to start, Future.get()
will throw an ExecutionException, and the service's state will be
Service.State.FAILED. If it has already finished starting, Future.get()
returns immediately. Cancelling this future has no effect on the service.public final Service.State startAndWait()
Servicestart().get(), this method throws no checked exceptions, and it cannot
be interrupted.
startAndWait in interface Servicepublic final boolean isRunning()
Servicetrue if this service is running.
isRunning in interface Servicepublic final Service.State state()
Service
state in interface Servicepublic final ListenableFuture<Service.State> stop()
Service
stop in interface ServiceFuture.get() will block until the service has finished shutting
down, and either returns Service.State.TERMINATED or throws an
ExecutionException. If it has already finished stopping,
Future.get() returns immediately. Cancelling this future has no effect
on the service.public final Service.State stopAndWait()
ServiceService.State.STARTING, startup will be cancelled. If this is Service.State.NEW, it is
terminated without having been started nor stopped. Unlike calling
stop().get(), this method throws no checked exceptions.
stopAndWait in interface Service
public final void addListener(Service.Listener listener,
Executor executor)
ServiceService.Listener to be executed on the given
executor. The listener will have the corresponding transition method called whenever the
service changes state. The listener will not have previous state changes replayed, so it is
suggested that listeners are added before the service starts.
There is no guaranteed ordering of execution of listeners, but any listener added through this method is guaranteed to be called whenever there is a state change.
Exceptions thrown by a listener will be propagated up to the executor. Any exception thrown
during Executor.execute (e.g., a RejectedExecutionException or an exception
thrown by inline execution) will be caught and
logged.
addListener in interface Servicelistener - the listener to run when the service changes state is completeexecutor - the executor in which the the listeners callback methods will be run. For fast,
lightweight listeners that would be safe to execute in any thread, consider
MoreExecutors.sameThreadExecutor().
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