batch 0.1.0

A lightweight and powerful batch library written in Dart. You can easily create a CLI batch program in Dart with this library.

A lightweight and powerful batch library written in Dart.

• 1. About
  • 1.1. Concepts
  • 1.2. Introduction
    • 1.2.1. Install Library
    • 1.2.2. Import It
    • 1.2.3. Use Batch
  • 1.3. Contribution
  • 1.4. License
  • 1.5. More Information

1. About

The batch library was created to make it easier to develop CLI program in Dart language. It supports scheduling using Cron and it is a very lightweight and powerful.

1.1. Concepts

The processing of the batch library is mainly performed using the following elements.

	Remarks
Job	Job is defined as the largest unit in a batch execution process in batch library. Job has a unique name and manages multiple Step.
Step	Step is defined as middle unit in a batch execution process in batch library. Step has a unique name and manages multiple Task.
Task	Task is defined as the smallest unit in a batch execution process in batch library. Task defines the specific process to be performed in the batch processing.

The concepts in the table above are in hierarchical order, with the top concepts encompassing the lower elements. However, this hierarchy only represents the layers of processing, and the higher level processing does not affect the lower level processing and vice versa.

1.2. Introduction

1.2.1. Install Library

With Dart:

 dart pub add batch

With Flutter:

 flutter pub add batch

1.2.2. Import It

import 'package:batch/batch.dart';

1.2.3. Use Batch

The easiest way to use the batch library is to create a class that implements Task and register it to Step and Job in the order you want to execute.

The execution schedule is specified for each job when creating a Job instance in the form of Cron.

When creating Job and Task instances, the names should be unique. However, you can use the same name for steps contained in different Job.

import 'package:batch/batch.dart';

void main() {
  // The name of the Job must be unique.
  final job1 = Job.from(name: 'Job1', cron: '*/1 * * * *')
    // The name of the Step must be unique in this Job.
    ..nextStep(
      Step.from(name: 'Step1')
        ..nextTask(SayHelloTask())
        ..nextTask(SayWorldTask()),
    )
    ..nextStep(
      Step.from(name: 'Step2')
        ..nextTask(SayHelloTask())
        ..nextTask(SayWorldTask()),
    );

  final job2 = Job.from(name: 'Job2', cron: '*/3 * * * *')
    ..nextStep(
      // You can reuse the Step name for another Job.
      Step.from(name: 'Step1')
        ..nextTask(SayHelloTask())
        ..nextTask(SayWorldTask()),
    );

  // Add jobs and execute.
  JobLauncher.newInstance()
    ..addJob(job1)
    ..addJob(job2)
    ..execute();
}

class SayHelloTask extends Task {
  @override
  Future<RepeatStatus> execute() async {
    print('Hello,');
    return RepeatStatus.finished;
  }
}

class SayWorldTask extends Task {
  @override
  Future<RepeatStatus> execute() async {
    print('World!');
    return RepeatStatus.finished;
  }
}

Also RepeatStatus is an important factor when defining Task processing.

A Task should always return RepeatStatus,　 and RepeatStatus.finished to finish the process of the Task. Another option to return in Task processing is RepeatStatus.continuable, but if this is returned, the same Task processing will be repeated over and over until RepeatStatus.finished is returned.

1.3. Contribution

If you would like to contribute to the development of this library, please create an issue or create a Pull Request.

Developer will respond to issues and review pull requests as quickly as possible.

1.4. License

Copyright (c) 2022, Kato Shinya. All rights reserved.
Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.

1.5. More Information

Batch was designed and implemented by Kato Shinya.

• Creator Profile
• License
• API Document
• Release Note
• Bug Report