io.druid.java.util.common.lifecycle

Class Lifecycle

java.lang.Object

io.druid.java.util.common.lifecycle.Lifecycle

public class Lifecycle
extends Object

A manager of object Lifecycles.

This object has methods for registering objects that should be started and stopped. The Lifecycle allows for two stages: Stage.NORMAL and Stage.LAST.

Things added at Stage.NORMAL will be started first (in the order that they are added to the Lifecycle instance) and then things added at Stage.LAST will be started.

The close operation goes in reverse order, starting with the last thing added at Stage.LAST and working backwards.

There are two sets of methods to add things to the Lifecycle. One set that will just add instances and enforce that start() has not been called yet. The other set will add instances and, if the lifecycle is already started, start them.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Lifecycle.Handler
static class	Lifecycle.Stage

Constructor Summary

Constructors

Constructor and Description
Lifecycle()

Method Summary

Modifier and Type	Method and Description
void	addHandler(Lifecycle.Handler handler) Adds a handler to the Lifecycle at the Stage.NORMAL stage.
void	addHandler(Lifecycle.Handler handler, Lifecycle.Stage stage) Adds a handler to the Lifecycle.
<T> T	addManagedInstance(T o) Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle at Stage.NORMAL.
<T> T	addManagedInstance(T o, Lifecycle.Stage stage) Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle.
void	addMaybeStartHandler(Lifecycle.Handler handler) Adds a handler to the Lifecycle at the Stage.NORMAL stage and starts it if the lifecycle has already been started.
void	addMaybeStartHandler(Lifecycle.Handler handler, Lifecycle.Stage stage) Adds a handler to the Lifecycle and starts it if the lifecycle has already been started.
<T> T	addMaybeStartManagedInstance(T o) Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle at Stage.NORMAL and starts it if the lifecycle has already been started.
<T> T	addMaybeStartManagedInstance(T o, Lifecycle.Stage stage) Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle and starts it if the lifecycle has already been started.
<T> T	addMaybeStartStartCloseInstance(T o) Adds an instance with a start() and/or close() method to the Lifecycle at Stage.NORMAL and starts it if the lifecycle has already been started.
<T> T	addMaybeStartStartCloseInstance(T o, Lifecycle.Stage stage) Adds an instance with a start() and/or close() method to the Lifecycle and starts it if the lifecycle has already been started.
<T> T	addStartCloseInstance(T o) Adds an instance with a start() and/or close() method to the Lifecycle at Stage.NORMAL.
<T> T	addStartCloseInstance(T o, Lifecycle.Stage stage) Adds an instance with a start() and/or close() method to the Lifecycle.
void	ensureShutdownHook()
boolean	isStarted()
void	join()
void	start()
void	stop()

Methods inherited from class java.lang.Object

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

Constructor Detail

Lifecycle

public Lifecycle()

Method Detail

addManagedInstance

public <T> T addManagedInstance(T o)

Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle at Stage.NORMAL. If the lifecycle has already been started, it throws an ISE

Parameters:

o - The object to add to the lifecycle

Throws:

ISE - addHandler(Handler, Stage)

addManagedInstance

public <T> T addManagedInstance(T o,
                                Lifecycle.Stage stage)

Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle. If the lifecycle has already been started, it throws an ISE

Parameters:

o - The object to add to the lifecycle

stage - The stage to add the lifecycle at

Throws:

ISE - addHandler(Handler, Stage)

addStartCloseInstance

public <T> T addStartCloseInstance(T o)

Adds an instance with a start() and/or close() method to the Lifecycle at Stage.NORMAL. If the lifecycle has already been started, it throws an ISE

Parameters:

o - The object to add to the lifecycle

Throws:

ISE - addHandler(Handler, Stage)

addStartCloseInstance

public <T> T addStartCloseInstance(T o,
                                   Lifecycle.Stage stage)

Adds an instance with a start() and/or close() method to the Lifecycle. If the lifecycle has already been started, it throws an ISE

Parameters:

o - The object to add to the lifecycle

stage - The stage to add the lifecycle at

Throws:

ISE - addHandler(Handler, Stage)

addHandler

public void addHandler(Lifecycle.Handler handler)

Adds a handler to the Lifecycle at the Stage.NORMAL stage. If the lifecycle has already been started, it throws an ISE

Parameters:

handler - The hander to add to the lifecycle

Throws:

ISE - addHandler(Handler, Stage)

addHandler

public void addHandler(Lifecycle.Handler handler,
                       Lifecycle.Stage stage)

Adds a handler to the Lifecycle. If the lifecycle has already been started, it throws an ISE

Parameters:

handler - The hander to add to the lifecycle

stage - The stage to add the lifecycle at

Throws:

ISE - indicates that the lifecycle has already been started and thus cannot be added to

addMaybeStartManagedInstance

public <T> T addMaybeStartManagedInstance(T o)
                                   throws Exception

Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle at Stage.NORMAL and starts it if the lifecycle has already been started.

Parameters:

o - The object to add to the lifecycle

Throws:

Exception - addMaybeStartHandler(Handler, Stage)

addMaybeStartManagedInstance

public <T> T addMaybeStartManagedInstance(T o,
                                          Lifecycle.Stage stage)
                                   throws Exception

Adds a "managed" instance (annotated with LifecycleStart and LifecycleStop) to the Lifecycle and starts it if the lifecycle has already been started.

Parameters:

o - The object to add to the lifecycle

stage - The stage to add the lifecycle at

Throws:

Exception - addMaybeStartHandler(Handler, Stage)

addMaybeStartStartCloseInstance

public <T> T addMaybeStartStartCloseInstance(T o)
                                      throws Exception

Adds an instance with a start() and/or close() method to the Lifecycle at Stage.NORMAL and starts it if the lifecycle has already been started.

Parameters:

o - The object to add to the lifecycle

Throws:

Exception - addMaybeStartHandler(Handler, Stage)

addMaybeStartStartCloseInstance

public <T> T addMaybeStartStartCloseInstance(T o,
                                             Lifecycle.Stage stage)
                                      throws Exception

Adds an instance with a start() and/or close() method to the Lifecycle and starts it if the lifecycle has already been started.

Parameters:

o - The object to add to the lifecycle

stage - The stage to add the lifecycle at

Throws:

Exception - addMaybeStartHandler(Handler, Stage)

addMaybeStartHandler

public void addMaybeStartHandler(Lifecycle.Handler handler)
                          throws Exception

Adds a handler to the Lifecycle at the Stage.NORMAL stage and starts it if the lifecycle has already been started.

Parameters:

handler - The hander to add to the lifecycle

Throws:

Exception - addMaybeStartHandler(Handler, Stage)

addMaybeStartHandler

public void addMaybeStartHandler(Lifecycle.Handler handler,
                                 Lifecycle.Stage stage)
                          throws Exception

Adds a handler to the Lifecycle and starts it if the lifecycle has already been started.

Parameters:

handler - The hander to add to the lifecycle

stage - The stage to add the lifecycle at

Throws:

Exception - an exception thrown from handler.start(). If an exception is thrown, the handler is *not* added

start

public void start()
           throws Exception

Throws:

Exception

stop

public void stop()

ensureShutdownHook

public void ensureShutdownHook()

join

public void join()
          throws InterruptedException

Throws:

InterruptedException

isStarted

public boolean isStarted()