需要幫助以避免類型轉換

Question

在重構以下代碼時，我需要幫助。 我要在此代碼中解決兩個主要問題：1. Rule1實現中的不安全類型轉換2.實現太多接口

  public interface Rule {
     public void execute(DataProvider dataProvider);
  }

  public interface DataProvider {
     // No common functions as of now 
  }

  public interface Rule1dataProvider extends DataProvider {
     // Functions required by Rule1
  }

  public class Rule1 implements Rule {
     public void execute(DataProvider dataProvider) {
       ADataProvider rule1DataProvider = <ADataProvider>dataProvider;
       // Other logic 
    }
  }

 public class EntityADataProvider implements Rule1DataProvider, Rule2DataProvider... {
    // Overrides functions of Rule 1 and Rule2 
 }

我在這里嘗試使用泛型，但無法找出正確的使用方式來消除類型轉換

Answer 1

使規則通用：

public interface Rule<T extends DataProvider> {
    public void execute(T dataProvider);
}

接着

public class Rule1 implements Rule<Rule1dataProvider> {
    @Override
    public void execute(Rule1dataProvider dataProvider) {            
        // ...
    }
}