Flutter工厂模式实现插件zam_factory_pattern的使用

提供了用于实现工厂模式的工具，该模式处理对象创建问题。

包含的内容

包含以下核心组件：

• Factory
• ModifiableFactory
• TypedFactory

详细了解这些组件，请查看 此处。

如何使用

final hondaFactory = HondaFactory({
  HondaCity: () => HondaCity(),
  HondaCivic: () => HondaCivic(),
  HondaAccord: () => HondaAccord(),
});

要了解更多信息，请移步到 示例部分 或查看 GitHub 上的示例。

状态

贡献者

• Amsakanna

许可证

BSD 3-Clause License

示例代码

example/lib/main.dart

import 'package:zam_factory_pattern/zam_factory_pattern.dart';

// 创建基类。
class HondaCar {
  void startEngine() {
    print('$runtimeType: Engine Started');
  }
}

// 创建子类。
class HondaCity extends HondaCar {}

class HondaCivic extends HondaCar {}

class HondaAccord extends HondaCar {}

class HondaJazz extends HondaCar {}

class HondaCrv extends HondaCar {}

// 创建工厂。
class HondaFactory extends TypedFactory<HondaCar> {
  const HondaFactory(Map<Type, Builder<HondaCar>> builders) : super(builders);
}

// 使用ModifiableFactoryMixin创建可修改的工厂。
class ModifiableHondaFactory extends HondaFactory with ModifiableFactoryMixin {
  const ModifiableHondaFactory(Map<Type, Builder<HondaCar>> builders)
      : super(builders);
}

// 现在让我们看看库可以提供什么功能。
void main() {
  //
  // 工厂
  //

  print('HondaFactory:\n');

  print('- 创建HondaFactory');
  final hondaFactory = HondaFactory({
    HondaCity: () => HondaCity(),
    HondaCivic: () => HondaCivic(),
    HondaAccord: () => HondaAccord(),
  });

  // 可以从工厂获取各种信息。
  print('Builders: ${hondaFactory.keys}'); // (HondaCity, HondaCivic, HondaAccord)
  print('Builder Count: ${hondaFactory.length}'); // 3
  print('isEmpty: ${hondaFactory.isEmpty}'); // false
  print('isNotEmpty: ${hondaFactory.isNotEmpty}'); // true
  print('包含HondaCivic: ${hondaFactory.contains(HondaCivic)}'); // true
  print('不包含HondaCivic: ${hondaFactory.doesNotContain(HondaCivic)}'); // false

  // 可以通过调用带有键值的createInstance方法来创建实例。
  print('- 创建Honda Accord。');
  final accord = hondaFactory.createInstance(HondaAccord);
  accord.startEngine(); // HondaAccord: Engine Started

  // 或者可以通过获取构建器并运行它来获取实例。
  print('- 手动创建Honda Accord。');
  final accordBuilder = hondaFactory.getBuilder(HondaAccord);
  final accord2 = accordBuilder();
  accord2.startEngine(); // HondaAccord: Engine Started

  // 当尝试调用未注册的构建器时会抛出错误。
  print('- 创建HondaJazz。');
  try {
    final jazz = hondaFactory
        .createInstance(HondaJazz); // 抛出BuilderNotFoundInFactoryException
    jazz.startEngine();
  } catch (exception) {
    // 打印以下内容：
    //
    // BuilderNotFoundInFactoryException 发生。
    // > 问题：在工厂中找不到键为 - HondaJazz 的构建器。
    // > 解决方案：请将一个构建器插入到工厂中，键为 - HondaJazz。
    print(exception);
  }

  //
  // 可修改的工厂
  //

  print('\nModifiableHondaFactory:\n');
  print('- 创建ModifiableHondaFactory。');
  final modifiableHondaFactory = ModifiableHondaFactory({
    HondaJazz: () => HondaJazz(),
    HondaCrv: () => HondaCrv(),
  });
  print('Builders: ${modifiableHondaFactory.keys}'); // (HondaJazz, HondaCrv)

  // 覆盖任何已存在的构建器。
  print('- 注册HondaCity');
  modifiableHondaFactory.registerBuilder(HondaCity, () => HondaCity());
  print('Builders: ${modifiableHondaFactory.keys}'); // (HondaJazz, HondaCrv, HondaCity)

  print('- 注册列表 - [HondaCivic, HondaAccord]。');
  modifiableHondaFactory.registerBuilders({
    HondaCivic: () => HondaCivic(),
    HondaAccord: () => HondaAccord(),
  });
  print('Builders: ${modifiableHondaFactory.keys}'); // (HondaJazz, HondaCrv, HondaCity, HondaCivic, HondaAccord)

  print('- 注销构建器 - HondaJazz。');
  modifiableHondaFactory.unregisterBuilder(HondaJazz);
  print('Builders: ${modifiableHondaFactory.keys}'); // (HondaCrv, HondaCity, HondaCivic, HondaAccord)

  print('- 注销列表 - [HondaCity, HondaAccord]。');
  modifiableHondaFactory.unregisterBuilders([HondaCity, HondaAccord]);
  print('Builders: ${modifiableHondaFactory.keys}'); // (HondaCrv, HondaCivic)

  print('- 从hondaFactory复制构建器。');
  modifiableHondaFactory.copyBuildersFrom(hondaFactory);
  print('Builders: ${modifiableHondaFactory.keys}'); // (HondaCrv, HondaCivic, HondaCity, HondaAccord)

  print('- 清除所有构建器。');
  modifiableHondaFactory.clear();
  print('Builders: ${modifiableHondaFactory.keys}'); // ()

  print('- 合并modifiableHondaFactory与hondaFactory。');
  modifiableHondaFactory.mergeWith(hondaFactory);
  print('Builders: ${modifiableHondaFactory.keys}'); // (HondaCity, HondaCivic, HondaAccord)
}