Returns {@code true} if this {@code Lifecycle} component should get started automatically by the container at the time that the containing {@link ApplicationContext} gets refreshed. <p>A value of {@code false} indicates that the component is intended to be started through an explicit {@link #start()} call instead, analogous to a plain {@link Lifecycle} implementation. @see #start() @see #getPhase()
Indicates that a Lifecycle component must stop if it is currently running. <p>The provided callback is used by the {@link LifecycleProcessor} to support an ordered, and potentially concurrent, shutdown of all components having a common shutdown order value. The callback <b>must</b> be executed after the {@code SmartLifecycle} component does indeed stop. <p>The {@link LifecycleProcessor} will call <i>only</i> this variant of the {@code stop} method; i.e. {@link Lifecycle#stop()} will not be called for {@code SmartLifecycle} implementations unless explicitly delegated to within the implementation of this method. @see #stop() @see #getPhase()
Return the phase value of this object.
An extension of the {@link Lifecycle} interface for those objects that require to be started upon ApplicationContext refresh and/or shutdown in a particular order. The {@link #isAutoStartup()} return value indicates whether this object should be started at the time of a context refresh. The callback-accepting {@link #stop(Runnable)} method is useful for objects that have an asynchronous shutdown process. Any implementation of this interface <i>must</i> invoke the callback's {@code run()} method upon shutdown completion to avoid unnecessary delays in the overall ApplicationContext shutdown.
<p>This interface extends {@link Phased}, and the {@link #getPhase()} method's return value indicates the phase within which this Lifecycle component should be started and stopped. The startup process begins with the <i>lowest</i> phase value and ends with the <i>highest</i> phase value ({@code Integer.MIN_VALUE} is the lowest possible, and {@code 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.
<p>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.
<p>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.
<p>Any {@code Lifecycle} components within the context that do not also implement {@code SmartLifecycle} will be treated as if they have a phase value of 0. That way a {@code SmartLifecycle} implementation may start before those {@code Lifecycle} components if it has a negative phase value, or it may start after those components if it has a positive phase value.
<p>Note that, due to the auto-startup support in {@code SmartLifecycle}, a {@code SmartLifecycle} bean instance will usually 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 {@code SmartLifecycle} beans.
@author Mark Fisher