Three classes with common methods

Question

I have 3 classes in Data Access project, and all 3 classes have many data access methods ( GetSomeList , InsertSomeData , UpdateSomeData …). All 3 classes have several methods that are same. I don't want to write same methods 3 times. What is best approach here?

One possible solution would be to define one common class that will be inherited. Is this good approach?

Example:

public abstract class CommonDataLayer
{
    public int CommonMethod()
    {
        Random random = new Random();
        int randomNumber = random.Next(0, 100);
        return randomNumber;
    }
}

public class FirstDataLayer : CommonDataLayer
{
    public int FirstMethod()
    {
        return CommonMethod() + 1;
    }
}

public class SecondDataLayer : CommonDataLayer
{
    public int SecondMethod()
    {
        return CommonMethod() + 2;
    }
}

public class ThirtDataLayer : CommonDataLayer
{
    public int ThirtMethod()
    {
        return CommonMethod() +3;
    }
}

Answer 1

为所有类创建一个超类，并为该超类创建通用方法实现。

Answer 2

A good approach is to:

One possible solution would be to define one common class that will be inherited. Is this good approach?

Yes

But in your code example, its not necessary to have FirstMethod , SecondMethod and ThirdMethod . You can invoke the CommonMethod directly from the derived class. You can override the CommonMethod if the derived method requires specific functionality.

public class FirstDataLayer : CommonDataLayer
{
    // This class uses CommonMethod from the Base Class
}


public class SecondDataLayer : CommonDataLayer
{
    @Override
    public int CommonMethod(){

    // EDIT code

          // Class specific implementation 
          return base.CommonMethod() +1;

    }
}

public class ThirdDataLayer : CommonDataLayer
{

    public int ThirdMethod(){

        // Class specific implementation 
        return base.CommonMethod() +2;

    }

 }