https://github.com/spring-projects/spring-framework: Spring Context (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2019 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 org.springframework.scheduling.config.ScheduledTaskRegistrar;


Annotation that marks a method to be scheduled. Exactly one of the cron, fixedDelay, or fixedRate attributes must be specified. 
The annotated method must expect no arguments. It will typically have a void return type; if not, the returned value will be ignored when called through the scheduler. 
Processing of @Scheduled annotations is performed by registering a ScheduledAnnotationBeanPostProcessor. This can be done manually or, more conveniently, through the <task:annotation-driven/> element or @EnableScheduling annotation. 
This annotation may be used as a meta-annotation to create custom
composed annotations with attribute overrides.

Author:Mark Fisher, Juergen Hoeller, Dave Syer, Chris Beams
See Also:
Since:3.0
/**
 * Annotation that marks a method to be scheduled. Exactly one of the
 * {@link #cron}, {@link #fixedDelay}, or {@link #fixedRate} attributes must be
 * specified.
 *
 * <p>The annotated method must expect no arguments. It will typically have
 * a {@code void} return type; if not, the returned value will be ignored
 * when called through the scheduler.
 *
 * <p>Processing of {@code @Scheduled} annotations is performed by
 * registering a {@link ScheduledAnnotationBeanPostProcessor}. This can be
 * done manually or, more conveniently, through the {@code <task:annotation-driven/>}
 * element or @{@link EnableScheduling} annotation.
 *
 * <p>This annotation may be used as a <em>meta-annotation</em> to create custom
 * <em>composed annotations</em> with attribute overrides.
 *
 * @author Mark Fisher
 * @author Juergen Hoeller
 * @author Dave Syer
 * @author Chris Beams
 * @since 3.0
 * @see EnableScheduling
 * @see ScheduledAnnotationBeanPostProcessor
 * @see Schedules
 */
@Target({ElementType.METHOD, ElementType.ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Repeatable(Schedules.class)
public @interface Scheduled {

	
A special cron expression value that indicates a disabled trigger: "-". 
This is primarily meant for use with ${...} placeholders,
allowing for external disabling of corresponding scheduled methods.

See Also:
Since:5.1
/**
	 * A special cron expression value that indicates a disabled trigger: {@value}.
	 * <p>This is primarily meant for use with <code>${...}</code> 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, "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 "-" indicates a disabled cron trigger, primarily meant for externally specified values resolved by a ${...} placeholder.

See Also:
Returns:an expression that can be parsed to a cron schedule
/**
	 * 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.
	 * <p>For example, {@code "0 * * * * MON-FRI"} means once per minute on weekdays
	 * (at the top of the minute - the 0th second).
	 * <p>The fields read from left to right are interpreted as follows.
	 * <ul>
	 * <li>second</li>
	 * <li>minute</li>
	 * <li>hour</li>
	 * <li>day of month</li>
	 * <li>month</li>
	 * <li>day of week</li>
	 * </ul>
	 * <p>The special value {@link #CRON_DISABLED "-"} indicates a disabled cron
	 * trigger, primarily meant for externally specified values resolved by a
	 * <code>${...}</code> placeholder.
	 * @return an expression that can be parsed to a cron schedule
	 * @see org.springframework.scheduling.support.CronSequenceGenerator
	 */
	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 server's local time zone will be used).

See Also:
Returns:a zone id accepted by TimeZone.getTimeZone(String), or an empty String to indicate the server's default time zone
Since:4.0
/**
	 * A time zone for which the cron expression will be resolved. By default, this
	 * attribute is the empty String (i.e. the server's local time zone will be used).
	 * @return a zone id accepted by {@link java.util.TimeZone#getTimeZone(String)},
	 * or an empty String to indicate the server'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 in milliseconds between the
end of the last invocation and the start of the next.

Returns:the delay in milliseconds
/**
	 * Execute the annotated method with a fixed period in milliseconds between the
	 * end of the last invocation and the start of the next.
	 * @return the delay in milliseconds
	 */
	long fixedDelay() default -1;

	
Execute the annotated method with a fixed period in milliseconds between the
end of the last invocation and the start of the next.

Returns:the delay in milliseconds as a String value, e.g. a placeholder or a java.time.Duration compliant value
Since:3.2.2
/**
	 * Execute the annotated method with a fixed period in milliseconds between the
	 * end of the last invocation and the start of the next.
	 * @return the delay in milliseconds as a String value, e.g. a placeholder
	 * or a {@link java.time.Duration#parse java.time.Duration} compliant value
	 * @since 3.2.2
	 */
	String fixedDelayString() default "";

	
Execute the annotated method with a fixed period in milliseconds between
invocations.

Returns:the period in milliseconds
/**
	 * Execute the annotated method with a fixed period in milliseconds between
	 * invocations.
	 * @return the period in milliseconds
	 */
	long fixedRate() default -1;

	
Execute the annotated method with a fixed period in milliseconds between
invocations.

Returns:the period in milliseconds as a String value, e.g. a placeholder or a java.time.Duration compliant value
Since:3.2.2
/**
	 * Execute the annotated method with a fixed period in milliseconds between
	 * invocations.
	 * @return the period in milliseconds as a String value, e.g. a placeholder
	 * or a {@link java.time.Duration#parse java.time.Duration} compliant value
	 * @since 3.2.2
	 */
	String fixedRateString() default "";

	
Number of milliseconds to delay before the first execution of a fixedRate or fixedDelay task. 
Returns:the initial delay in milliseconds
Since:3.2
/**
	 * Number of milliseconds to delay before the first execution of a
	 * {@link #fixedRate} or {@link #fixedDelay} task.
	 * @return the initial delay in milliseconds
	 * @since 3.2
	 */
	long initialDelay() default -1;

	
Number of milliseconds to delay before the first execution of a fixedRate or fixedDelay task. 
Returns:the initial delay in milliseconds as a String value, e.g. a placeholder or a java.time.Duration compliant value
Since:3.2.2
/**
	 * Number of milliseconds to delay before the first execution of a
	 * {@link #fixedRate} or {@link #fixedDelay} task.
	 * @return the initial delay in milliseconds as a String value, e.g. a placeholder
	 * or a {@link java.time.Duration#parse java.time.Duration} compliant value
	 * @since 3.2.2
	 */
	String initialDelayString() default "";

}