建造者模式【构建模式】

建造者模式

Separate the construction of a complex object from its representation so that
the same construction process can create different representations.
将一个复杂对象的构建与其表示分离，以便相同的构建过程可以创建不同的表示。

public class Constuctor {
    /**
     * 建造者模式：
     * Separate the construction of a complex object from its representation so that
     * the same construction process can create different representations.
     * 将一个复杂对象的构建与其表示分离，以便相同的构建过程可以创建不同的表示。
     */

    @Test
    public void all() {
        BenzFactory.series1().run();
        BenzFactory.series2().run();
    }
}

/**
 * 1）定义零件类型
 */
enum CarPartEnum {
    ENGINE, ALARM, VEHICLE_MOUNTED_SYSTEM, BRAKE;
}

/**
 * 2）定义零件操作
 */
interface CarPart {
    String name();

    void doWork();
}

/**
 * 3）定义具体的零件
 */
@Builder
@Slf4j
class CarPartImpl implements CarPart {
    private final String name;

    @Override
    public void doWork() {
        log.info("{} is working now", name);
    }

    @Override
    public String name() {
        return name;
    }
}

/**
 * 4）整合零件与操作的模型类，核心组件
 */
class CarModel {
    private final List<CarPart> parts = Lists.newArrayList();

    public CarModel addPart(CarPart carPart) {
        parts.add(carPart);
        return this;
    }

    public final void run() {
        parts.forEach(CarPart::doWork);
    }
}

/**
 * 5）抽象建造者
 */
interface CarBuilder {
    CarModel build();
}

/**
 * 6）具体建造者
 */
class BenzSeries1CarBuilder implements CarBuilder {
    private static final CarBuilder CAR_BUILDER = new BenzSeries1CarBuilder();

    private BenzSeries1CarBuilder() {
    }

    public static CarBuilder get() {
        return CAR_BUILDER;
    }

    @Override
    public CarModel build() {
        return new CarModel()
                .addPart(new CarPartImpl(CarPartEnum.ENGINE.name()))
                .addPart(new CarPartImpl(CarPartEnum.BRAKE.name()));
    }
}

class BenzSeries2CarBuilder implements CarBuilder {
    private static final CarBuilder CAR_BUILDER = new BenzSeries2CarBuilder();

    private BenzSeries2CarBuilder() {
    }

    public static CarBuilder get() {
        return CAR_BUILDER;
    }

    @Override
    public CarModel build() {
        return new CarModel()
                .addPart(new CarPartImpl(CarPartEnum.ENGINE.name()))
                .addPart(new CarPartImpl(CarPartEnum.VEHICLE_MOUNTED_SYSTEM.name()))
                .addPart(new CarPartImpl(CarPartEnum.ALARM.name()))
                .addPart(new CarPartImpl(CarPartEnum.BRAKE.name()));
    }
}

/**
 *  7）实例工厂
 */
class BenzFactory {
    public static CarModel series1() {
        return BenzSeries1CarBuilder.get().build();
    }

    public static CarModel series2() {
        return BenzSeries2CarBuilder.get().build();
    }
}