com.github.kagkarlsson.scheduler.task.helper.ScheduleRecurringOnStartup Maven / Gradle / Ivy

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Simple persistent scheduler for scheduled tasks, recurring or ad-hoc.
There is a newer version: 15.0.0
/**
 * Copyright (C) Gustav Karlsson
 *
 * 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 com.github.kagkarlsson.scheduler.task.helper;

import com.github.kagkarlsson.scheduler.Clock;
import com.github.kagkarlsson.scheduler.ScheduledExecution;
import com.github.kagkarlsson.scheduler.SchedulerClient;
import com.github.kagkarlsson.scheduler.task.ExecutionComplete;
import com.github.kagkarlsson.scheduler.task.Task;
import com.github.kagkarlsson.scheduler.task.TaskInstance;
import com.github.kagkarlsson.scheduler.task.schedule.Schedule;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.time.Duration;
import java.time.Instant;
import java.util.Optional;

class ScheduleRecurringOnStartup implements ScheduleOnStartup {
    private static final Logger LOG = LoggerFactory.getLogger(ScheduleRecurringOnStartup.class);
    private final Schedule schedule;
    private final String instance;
    private final T data;

    ScheduleRecurringOnStartup(String instance, T data, Schedule schedule) {
        this.instance = instance;
        this.data = data;
        this.schedule = schedule;
    }

    @Override
    public void apply(SchedulerClient scheduler, Clock clock, Task task) {
        final TaskInstance instanceWithoutData = task.instance(this.instance);
        final Optional> preexistingExecution = scheduler.getScheduledExecution(instanceWithoutData);

        if (schedule.isDisabled()) {
            if (preexistingExecution.isPresent()) {
                LOG.info("Task-instance '{}' has a Schedule that has been marked as disabled. Removing existing execution with execution-time '{}'.",
                    instanceWithoutData, preexistingExecution.get().getExecutionTime());
                tryCancel(scheduler, instanceWithoutData);
            } else {
                LOG.info("Task-instance '{}' has a Schedule that has been marked as disabled. Will not schedule a new execution", instanceWithoutData);
            }
            return;
        }

        if (preexistingExecution.isPresent()) {
            Optional newNextExecutionTime = checkForNewExecutionTime(clock, instanceWithoutData, preexistingExecution.get());

            newNextExecutionTime.ifPresent(instant -> {
                // Intentionally leaving out data here, since we do not want to update existing data
                scheduler.reschedule(instanceWithoutData, instant);
            });

        } else {
            // No preexisting execution, create initial one
            final Instant initialExecutionTime = schedule.getInitialExecutionTime(clock.now());
            LOG.info("Creating initial execution for task-instance '{}'. Next execution-time: {}", instanceWithoutData, initialExecutionTime);
            scheduler.schedule(getSchedulableInstance(task), initialExecutionTime);
        }
    }

    private void tryCancel(SchedulerClient scheduler, TaskInstance instanceWithoutData) {
        try {
            scheduler.cancel(instanceWithoutData);
        } catch (RuntimeException e) {
            LOG.warn("Failed to cancel existing execution for a Task with a Scheduled marked as disabled. " +
                "May happen if another instance already did it, or if it is currently executing.", e);
        }
    }

    Optional checkForNewExecutionTime(Clock clock, TaskInstance instanceWithoutData, ScheduledExecution