org.springframework.scheduling.annotation.Scheduled Maven / Gradle / Ivy
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* Copyright 2002-2024 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
*
* https://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.
*/
package org.springframework.scheduling.annotation;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Repeatable;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;
import org.springframework.aot.hint.annotation.Reflective;
import org.springframework.scheduling.config.ScheduledTaskRegistrar;
/**
* Annotation that marks a method to be scheduled. For periodic tasks, exactly one
* of the {@link #cron}, {@link #fixedDelay}, or {@link #fixedRate} attributes
* must be specified, and additionally an optional {@link #initialDelay}.
* For a one-time task, it is sufficient to just specify an {@link #initialDelay}.
*
* The annotated method must not accept arguments. It will typically have
* a {@code void} return type; if not, the returned value will be ignored
* when called through the scheduler.
*
*
Methods that return a reactive {@code Publisher} or a type which can be adapted
* to {@code Publisher} by the default {@code ReactiveAdapterRegistry} are supported.
* The {@code Publisher} must support multiple subsequent subscriptions. The returned
* {@code Publisher} is only produced once, and the scheduling infrastructure then
* periodically subscribes to it according to configuration. Values emitted by
* the publisher are ignored. Errors are logged at {@code WARN} level, which
* doesn't prevent further iterations. If a fixed delay is configured, the
* subscription is blocked in order to respect the fixed delay semantics.
*
*
Kotlin suspending functions are also supported, provided the coroutine-reactor
* bridge ({@code kotlinx.coroutine.reactor}) is present at runtime. This bridge is
* used to adapt the suspending function to a {@code Publisher} which is treated
* the same way as in the reactive method case (see above).
*
*
Processing of {@code @Scheduled} annotations is performed by registering a
* {@link ScheduledAnnotationBeanPostProcessor}. This can be done manually or,
* more conveniently, through the {@code
This annotation can be used as a {@linkplain Repeatable repeatable}
* annotation. If several scheduled declarations are found on the same method,
* each of them will be processed independently, with a separate trigger firing
* for each of them. As a consequence, such co-located schedules may overlap
* and execute multiple times in parallel or in immediate succession.
*
*
This annotation may be used as a meta-annotation to create custom
* composed annotations with attribute overrides.
*
* @author Mark Fisher
* @author Juergen Hoeller
* @author Dave Syer
* @author Chris Beams
* @author Victor Brown
* @author Sam Brannen
* @since 3.0
* @see EnableScheduling
* @see ScheduledAnnotationBeanPostProcessor
* @see Schedules
*/
@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Repeatable(Schedules.class)
@Reflective
public @interface Scheduled {
/**
* A special cron expression value that indicates a disabled trigger: {@value}.
*
This is primarily meant for use with ${...} placeholders,
* allowing for external disabling of corresponding scheduled methods.
* @since 5.1
* @see ScheduledTaskRegistrar#CRON_DISABLED
*/
String CRON_DISABLED = ScheduledTaskRegistrar.CRON_DISABLED;
/**
* A cron-like expression, extending the usual UN*X definition to include triggers
* on the second, minute, hour, day of month, month, and day of week.
*
For example, {@code "0 * * * * MON-FRI"} means once per minute on weekdays
* (at the top of the minute - the 0th second).
*
The fields read from left to right are interpreted as follows.
*
* - second
* - minute
* - hour
* - day of month
* - month
* - day of week
*
* The special value {@link #CRON_DISABLED "-"} indicates a disabled cron
* trigger, primarily meant for externally specified values resolved by a
* ${...} placeholder.
* @return an expression that can be parsed to a cron schedule
* @see org.springframework.scheduling.support.CronExpression#parse(String)
*/
String cron() default "";
/**
* A time zone for which the cron expression will be resolved. By default, this
* attribute is the empty String (i.e. the scheduler's time zone will be used).
* @return a zone id accepted by {@link java.util.TimeZone#getTimeZone(String)},
* or an empty String to indicate the scheduler's default time zone
* @since 4.0
* @see org.springframework.scheduling.support.CronTrigger#CronTrigger(String, java.util.TimeZone)
* @see java.util.TimeZone
*/
String zone() default "";
/**
* Execute the annotated method with a fixed period between the end of the
* last invocation and the start of the next.
*
The time unit is milliseconds by default but can be overridden via
* {@link #timeUnit}.
*
NOTE: With virtual threads, fixed rates and cron triggers are recommended
* over fixed delays. Fixed-delay tasks operate on a single scheduler thread
* with {@link org.springframework.scheduling.concurrent.SimpleAsyncTaskScheduler}.
* @return the delay
*/
long fixedDelay() default -1;
/**
* Execute the annotated method with a fixed period between the end of the
* last invocation and the start of the next.
*
The time unit is milliseconds by default but can be overridden via
* {@link #timeUnit}.
*
This attribute variant supports Spring-style "${...}" placeholders
* as well as SpEL expressions.
*
NOTE: With virtual threads, fixed rates and cron triggers are recommended
* over fixed delays. Fixed-delay tasks operate on a single scheduler thread
* with {@link org.springframework.scheduling.concurrent.SimpleAsyncTaskScheduler}.
* @return the delay as a String value — for example, a placeholder
* or a {@link java.time.Duration#parse java.time.Duration} compliant value
* @since 3.2.2
* @see #fixedDelay()
*/
String fixedDelayString() default "";
/**
* Execute the annotated method with a fixed period between invocations.
*
The time unit is milliseconds by default but can be overridden via
* {@link #timeUnit}.
* @return the period
*/
long fixedRate() default -1;
/**
* Execute the annotated method with a fixed period between invocations.
*
The time unit is milliseconds by default but can be overridden via
* {@link #timeUnit}.
*
This attribute variant supports Spring-style "${...}" placeholders
* as well as SpEL expressions.
* @return the period as a String value — for example, a placeholder
* or a {@link java.time.Duration#parse java.time.Duration} compliant value
* @since 3.2.2
* @see #fixedRate()
*/
String fixedRateString() default "";
/**
* Number of units of time to delay before the first execution of a
* {@link #fixedRate} or {@link #fixedDelay} task.
*
The time unit is milliseconds by default but can be overridden via
* {@link #timeUnit}.
* @return the initial
* @since 3.2
*/
long initialDelay() default -1;
/**
* Number of units of time to delay before the first execution of a
* {@link #fixedRate} or {@link #fixedDelay} task.
*
The time unit is milliseconds by default but can be overridden via
* {@link #timeUnit}.
*
This attribute variant supports Spring-style "${...}" placeholders
* as well as SpEL expressions.
* @return the initial delay as a String value — for example, a placeholder
* or a {@link java.time.Duration#parse java.time.Duration} compliant value
* @since 3.2.2
* @see #initialDelay()
*/
String initialDelayString() default "";
/**
* The {@link TimeUnit} to use for {@link #fixedDelay}, {@link #fixedDelayString},
* {@link #fixedRate}, {@link #fixedRateString}, {@link #initialDelay}, and
* {@link #initialDelayString}.
*
Defaults to {@link TimeUnit#MILLISECONDS}.
*
This attribute is ignored for {@linkplain #cron() cron expressions}
* and for {@link java.time.Duration} values supplied via {@link #fixedDelayString},
* {@link #fixedRateString}, or {@link #initialDelayString}.
* @return the {@code TimeUnit} to use
* @since 5.3.10
*/
TimeUnit timeUnit() default TimeUnit.MILLISECONDS;
/**
* A qualifier for determining a scheduler to run this scheduled method on.
*
Defaults to an empty String, suggesting the default scheduler.
*
May be used to determine the target scheduler to be used,
* matching the qualifier value (or the bean name) of a specific
* {@link org.springframework.scheduling.TaskScheduler} or
* {@link java.util.concurrent.ScheduledExecutorService} bean definition.
* @since 6.1
* @see org.springframework.scheduling.SchedulingAwareRunnable#getQualifier()
*/
String scheduler() default "";
}