/*
* Copyright 2002-2018 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
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package org.springframework.context;
An extension of the 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 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 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 SmartLifecycle beans.
Author: Mark Fisher, Juergen Hoeller See Also: Since: 3.0
/**
* 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
* @author Juergen Hoeller
* @since 3.0
* @see LifecycleProcessor
* @see ConfigurableApplicationContext
*/
public interface SmartLifecycle extends Lifecycle, Phased {
The default phase for SmartLifecycle: Integer.MAX_VALUE. This is different from the common phase 0 associated with regular Lifecycle implementations, putting the typically auto-started SmartLifecycle beans into a separate later shutdown phase.
See Also: Since: 5.1
/**
* The default phase for {@code SmartLifecycle}: {@code Integer.MAX_VALUE}.
* <p>This is different from the common phase 0 associated with regular
* {@link Lifecycle} implementations, putting the typically auto-started
* {@code SmartLifecycle} beans into a separate later shutdown phase.
* @since 5.1
* @see #getPhase()
* @see org.springframework.context.support.DefaultLifecycleProcessor#getPhase(Lifecycle)
*/
int DEFAULT_PHASE = Integer.MAX_VALUE;
Returns 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.
The default implementation returns true.
See Also:
/**
* 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.
* <p>The default implementation returns {@code true}.
* @see #start()
* @see #getPhase()
* @see LifecycleProcessor#onRefresh()
* @see ConfigurableApplicationContext#refresh()
*/
default boolean isAutoStartup() {
return true;
}
Indicates that a Lifecycle component must stop if it is currently running.
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.
The default implementation delegates to Lifecycle.stop() and immediately triggers the given callback in the calling thread. Note that there is no synchronization between the two, so custom implementations may at least want to put the same steps within their common lifecycle monitor (if any).
See Also:
/**
* 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.
* <p>The default implementation delegates to {@link #stop()} and immediately
* triggers the given callback in the calling thread. Note that there is no
* synchronization between the two, so custom implementations may at least
* want to put the same steps within their common lifecycle monitor (if any).
* @see #stop()
* @see #getPhase()
*/
default void stop(Runnable callback) {
stop();
callback.run();
}
Return the phase that this lifecycle object is supposed to run in.
The default implementation returns DEFAULT_PHASE in order to let stop callbacks execute after regular Lifecycle implementations.
See Also:
/**
* Return the phase that this lifecycle object is supposed to run in.
* <p>The default implementation returns {@link #DEFAULT_PHASE} in order to
* let stop callbacks execute after regular {@code Lifecycle} implementations.
* @see #isAutoStartup()
* @see #start()
* @see #stop(Runnable)
* @see org.springframework.context.support.DefaultLifecycleProcessor#getPhase(Lifecycle)
*/
@Override
default int getPhase() {
return DEFAULT_PHASE;
}
}