ScheduleWithFixedDelay.java

/**
 * Copyright (c) 2012-2017, jcabi.com
 * All rights reserved.
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 *
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package com.jcabi.aspects;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.util.concurrent.TimeUnit;

/**
 * Schedules the method to run with fixed delay, automatically.
 *
 * <p>For example, you want a method to do something every minute:
 *
 * <pre> @ScheduleWithFixedDelay(delay = 1, unit = TimeUnit.MINUTES)
 * public class Bucket implements Runnable, Closeable {
 *   @Override
 *   void run() {
 *     // do some routine job
 *   }
 *   @Override
 *   void close() {
 *     // close operations
 *   }
 * }</pre>
 *
 * <p>Execution will be started as soon as you make an instance of the class,
 * and will be stopped when you call {@code close()}:
 *
 * <pre> Bucket bucket = new Bucket();
 * // some time later
 * bucket.close();</pre>
 *
 * <p>In order to be executed the class should implement either
 * {@link Runnable} or {@link java.util.concurrent.Callable}. In order to
 * be closed and stopped, your the class should implement
 * {@link java.io.Closeable} and its {@code close()}
 * method should be explicitly called
 * at the moment you want it to stop.
 *
 * <p><b>NOTE:</b> It should be pointed out that in order to ensure that there
 * are no duplicate executions, you can only schedule an execution once between
 * all equal objects (i.e. instances that are equal as per
 * {@link Object#equals(Object)})). Invoking the same method multiple times,
 * without stopping it first, will result in an {@link IllegalStateException}
 * being thrown.
 *
 * @author Yegor Bugayenko (yegor@tpc2.com)
 * @version $Id: 0f0f9614675d072044ea863a4d5f93538845b101 $
 * @since 0.7.16
 * @see <a href="http://aspects.jcabi.com">http://aspects.jcabi.com/</a>
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface ScheduleWithFixedDelay {

    /**
     * Delay, in time units.
     */
    int delay() default 1;

    /**
     * Time units of delay.
     */
    TimeUnit unit() default TimeUnit.MINUTES;

    /**
     * How long to wait for the task to finish after shutdown in await units.
     */
    int await() default 1;

    /**
     * Time units of await time.
     */
    TimeUnit awaitUnit() default TimeUnit.MINUTES;

    /**
     * How many times to do a forceful shutdown after await time.
     * Each forceful shutdown attempt will be followed by a 1 second wait to
     * allow the threads to finish.
     */
    int shutdownAttempts() default 1;

    /**
     * Total number of fixed threads.
     */
    int threads() default 1;

    /**
     * Be less verbose.
     */
    boolean verbose() default true;
}