java设计问题：如何将验证检查重构为另一个方法

Question

我有一个巨大的验证方法，我想重构它。这里有一个例子。我已经提供了初步的验证，以及我自己的建议。你认为这是一个很好的重构方法还是有更好的重构方法

谢谢

public void validate() {

   MyException myException= new MyException();
   try {
      if (!isRule1()) {
         throw MyException.invalidRule(Rule1);
      }
   }
   catch (MyException e) {
      myException.addWrappedException(e);
   }

   try{
       f (!isRule2()) {
             throw MyException.invalidRule(Rule2);
          }
       }
       catch (MyException e) {
          myException.addWrappedException(e);
   }

   ////continue checking...
}

下面是我想要如何重构它们：

public void validate() {


   MyException myException= new MyException();
   validateRule1(myException);
   validateRule2(myException);
   //continue validating....
}
private void validateRule1(myException){
   try {
      if (!isRule1()) {
         throw MyException.invalidRule(Rule1);
      }
   }
   catch (MyException e) {
      myException.addWrappedException(e);
   }
}
private void validateRule2(myException){
   try {
      if (!isRule2()) {
         throw MyException.invalidRule(Rule2);
      }
   }
   catch (MyException e) {
      myException.addWrappedException(e);
   }
}

Answer 1

试一试怎么样

MyException myException= new MyException();
if (!isRule1())
    myException.addWrappedException(MyException.invalidRule(Rule1));

或

MyException myException= new MyException();
myException.addWrappedException(checkRule1());

其中checkRule1（）返回异常或null，addWrappedException忽略null

或

MyException myException= new MyException();
checkRule1(myException);

Answer 2

一定要从Replace Method with Method Object开始。这没有风险，你也不应该用这么大的方法来害怕。那么你的方法似乎很好。。。只需确保重命名validateRule1；）

Answer 3

你可以在这里使用装饰图案。创建一个具有单个方法validate（）的接口，然后创建实现此接口的不同类，该接口包含验证代码。然后可以对构建的对象调用validate，这将通过所有其他验证展开

这还可以提高代码的模块性，使您能够独立地对验证进行单元测试。您还可以根据需要从链中轻松添加或删除验证

下面是一个简单的例子

public interface Validator {
  void validate(Object input) throws ValidationException
}

public class ValidationOne implements Validator {
  protected Validator validator;

  public ValidationOne(Validator validator) {
    this.validator = validator;
  }

  public void validate(Object input) throws ValidationException {
    if (validator != null) 
      validator.validate(input);
    // do specific ValidationOne checks
    if (!isValid(input)) throw new ValidationException()
  }
}

public class ValidationTwo implements Validator {
  protected Validator validator;

  public ValidationTwo(Validator validator) {
    this.validator = validator;
  }

  public void validate(Object input) throws ValidationException {
    if (validator != null)
      validator.validate(input);
    // do specific ValidationTwo checks
    if (!isValid(input)) throw new ValidationException()
  }
}


public class Tester {

   public void runValidations(Object obj) {
      Validator validator = new ValidationOne(null);
      validator = new ValidationTwo(validator);
      // continue adding validations as needed
      try {
        validator.validate(obj);
      } catch (ValidationException e) {
        System.err.println("Validation error occurred");
      }
   }
}