io.micronaut.scheduling.NextFireTime Maven / Gradle / Ivy
/*
* Copyright 2017-2019 original 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.
*/
package io.micronaut.scheduling;
import java.time.Duration;
import java.time.ZonedDateTime;
import java.util.function.Supplier;
import io.micronaut.core.annotation.Internal;
import io.micronaut.scheduling.cron.CronExpression;
/**
* Represents the next fire time for a cron expression.
*
* @author croudet
* @since 1.2.1
*/
@Internal
final class NextFireTime implements Supplier {
private Duration duration;
private ZonedDateTime nextFireTime;
private final CronExpression cron;
/**
* Default constructor.
*
* @param cron A cron expression
*/
NextFireTime(CronExpression cron) {
this.cron = cron;
nextFireTime = ZonedDateTime.now();
}
@Override
public Duration get() {
ZonedDateTime now = ZonedDateTime.now();
// check if the task have fired too early
computeNextFireTime(now.isAfter(nextFireTime) ? now : nextFireTime);
return duration;
}
private void computeNextFireTime(ZonedDateTime currentFireTime) {
nextFireTime = cron.nextTimeAfter(currentFireTime);
duration = Duration.ofMillis(nextFireTime.toInstant().toEpochMilli() - ZonedDateTime.now().toInstant().toEpochMilli());
}
}