Switch, factoría, tester/doer

Ejemplo de como quitar un switch y sustituirlo por una factoria:

public void ProcessCustomer(CustomerMessage message)

{

  switch (message.CustomerCategory)

  {

    case Category.Gold:

      ProcessGoldCustomer(message);

      break;

    case Category.Silver:

      ProcessSilverCustomer(message);

      break;

    case Category.Bronze:

      ProcessBronzeCustomer(message);

      break;

  }

}

 

Ejemplo con factoría:

 

public interface ICustomerProcessor

{

  void Process(CustomerMessage message);

}

 

public class GoldCustomerProcessor : ICustomerProcessor {...}

public class SilverCustomerProcessor : ICustomerProcessor {...}

public class BronzeCustomerProcessor : ICustomerProcessor {...}

 

public class CustomerProcessorFactory

{

  public ICustomerProcessor Create(Category category) {

    switch (category) {   
      case Category.Gold: 

        return new GoldCustomerProcessor();

    }

    ...

  }

}

 

public void ProcessCustomer(CustomerMessage message)

{

  var factory = new CustomerProcessorFactory();

  var processor = factory.Create(message.CustomerCategory);

  processor.Process(message);

}

 

Ejemplo patrón Tester/Doer:

 

public interface ICustomerProcessor

{

  bool CanProcess(CustomerMessage message);

  void Process(CustomerMessage message);

}

 

public class GoldCustomerProcessor : ICustomerProcessor

{

  public bool CanProcess(CustomerMessage message)

  {

    return message.CustomerCategory == Category.Gold;

  }

   

  public void Process(CustomerMessage message) {...}

}

 

public class SilverCustomerProcessor : ICustomerProcessor {...}

public class BronzeCustomerProcessor : ICustomerProcessor {...}

 

public void ProcessCustomer(CustomerMessage message)

{

  var processor = this.processors.Single(x => x.CanProcess(message));

  processor.Process(message);

}