public interface SmartLifecycle extends Lifecycle, Phased
Lifecycle interface for those objects that require to
be started upon ApplicationContext refresh and/or shutdown in a particular order.
The isAutoStartup() return value indicates whether this object should
be started at the time of a context refresh. The callback-accepting
stop(Runnable) method is useful for objects that have an asynchronous
shutdown process. Any implementation of this interface must invoke the
callback's run() method upon shutdown completion to avoid unnecessary delays
in the overall ApplicationContext shutdown.
This interface extends Phased, and the Phased.getPhase() method's
return value indicates the phase within which this Lifecycle component should
be started and stopped. The startup process begins with the lowest
phase value and ends with the highest phase value (Integer.MIN_VALUE
is the lowest possible, and Integer.MAX_VALUE is the highest possible). The
shutdown process will apply the reverse order. Any components with the
same value will be arbitrarily ordered within the same phase.
Example: if component B depends on component A having already started, then component A should have a lower phase value than component B. During the shutdown process, component B would be stopped before component A.
Any explicit "depends-on" relationship will take precedence over the phase order such that the dependent bean always starts after its dependency and always stops before its dependency.
Any Lifecycle components within the context that do not also implement SmartLifecycle will be treated as if they have a phase value of 0. That way a SmartLifecycle implementation may start before those Lifecycle components if it has a negative phase value, or it may start after those components if it has a positive phase value.
Note that, due to the auto-startup support in SmartLifecycle, a SmartLifecycle bean instance will get initialized on startup of the application context in any case. As a consequence, the bean definition lazy-init flag has very limited actual effect on SmartLifecycle beans.
LifecycleProcessor,
ConfigurableApplicationContext| 限定符和类型 | 方法和说明 |
|---|---|
boolean |
isAutoStartup()
Returns
true if this Lifecycle component should get
started automatically by the container at the time that the containing
ApplicationContext gets refreshed. |
void |
stop(java.lang.Runnable callback)
Indicates that a Lifecycle component must stop if it is currently running.
|
boolean isAutoStartup()
true if this Lifecycle component should get
started automatically by the container at the time that the containing
ApplicationContext gets refreshed.
A value of false indicates that the component is intended to
be started through an explicit Lifecycle.start() call instead, analogous
to a plain Lifecycle implementation.
Lifecycle.start(),
Phased.getPhase(),
LifecycleProcessor.onRefresh(),
ConfigurableApplicationContext#refresh()void stop(java.lang.Runnable callback)
The provided callback is used by the LifecycleProcessor to support
an ordered, and potentially concurrent, shutdown of all components having a
common shutdown order value. The callback must be executed after
the SmartLifecycle component does indeed stop.
The LifecycleProcessor will call only this variant of the
stop method; i.e. Lifecycle.stop() will not be called for
SmartLifecycle implementations unless explicitly delegated to within
the implementation of this method.