JobChainingUsingSeparateTasksMain.java

/**
 * Copyright (C) Gustav Karlsson
 * <p>
 * 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
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * 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.examples;

import com.github.kagkarlsson.examples.helpers.Example;
import com.github.kagkarlsson.scheduler.Scheduler;
import com.github.kagkarlsson.scheduler.task.*;
import com.github.kagkarlsson.scheduler.task.helper.CustomTask;
import com.github.kagkarlsson.scheduler.task.helper.Tasks;

import javax.sql.DataSource;
import java.io.Serializable;
import java.time.Duration;
import java.time.Instant;

public class JobChainingUsingSeparateTasksMain extends Example {

    public static void main(String[] args) {
        new JobChainingUsingSeparateTasksMain().runWithDatasource();
    }

    @Override
    public void run(DataSource dataSource) {

        final CustomTask<JobId> jobStep1 = Tasks.custom("job-step-1", JobId.class)
            .execute((taskInstance, executionContext) -> {
                System.out.println("Step1 ran. Job: " + taskInstance.getData());
                return new OnCompleteRemoveAndCreateNextStep("job-step-2");
            });

        final CustomTask<JobId> jobStep2 = Tasks.custom("job-step-2", JobId.class)
            .execute((taskInstance, executionContext) -> {
                System.out.println("Step2 ran. Removing multistep-job. Job: " + taskInstance.getData());
                return new CompletionHandler.OnCompleteRemove<>();
            });

        final Scheduler scheduler = Scheduler
            .create(dataSource, jobStep1, jobStep2)
            .enableImmediateExecution()  // will cause job scheduled to now() to run directly
            .pollingInterval(Duration.ofSeconds(10))
            .build();

        scheduler.start();

        sleep(1_000);

        // Schedule a multistep job. Simulate some instance-specific data, id=507
        scheduler.schedule(jobStep1.instance("job-507", new JobId(507)), Instant.now()); // both steps will run directly
    }

    public static class JobId implements Serializable {
        private static long serialVersionUID = 1L;
        public int id;

        public JobId(int id) {
            this.id = id;
        }

        @Override
        public String toString() {
            return "JobId{" +
                "id=" + id +
                '}';
        }
    }

    class OnCompleteRemoveAndCreateNextStep implements CompletionHandler<JobId> {
        private final String newTaskName;

        public OnCompleteRemoveAndCreateNextStep(String newTaskName) {
            this.newTaskName = newTaskName;
        }

        @Override
        public void complete(ExecutionComplete executionComplete, ExecutionOperations<JobId> executionOperations) {
            TaskInstance taskInstance = executionComplete.getExecution().taskInstance;
            TaskInstance<JobId> nextInstance = new TaskInstance<>(newTaskName, taskInstance.getId(), (JobId) taskInstance.getData());
            executionOperations.removeAndScheduleNew(SchedulableInstance.of(nextInstance, Instant.now()));
        }
    }

}