Question

I have one class with two important functions:

public class Foo {
    //plenty of properties here
    void DoSomeThing(){/*code to calculate results*/}
    void SaveSomething(){/* code to save the results in DB*/}

}

SaveSomething() uses the results calculated in DoSomeThing().

the problem is that we must not to call SaveSomething() before DoSomeThing() or if that happens the results are not true results. I mean order of calls are important, this is a problem in maintaining the code.(when new one is added to team).

is there any way to manage this?

I think of 3 methods as below

1. throwing exception in SaveSomething() if it called before DoSomeThing()

2. having a bool that are set in DoSomeThing() and SaveSomething() code changes to:

   bool resultsAreCalculated = false;
   void SaveSomething(){
       if (!resultsAreCalculated) {
           DoSomeThing();
           // the resultsAreCalculated = true; is set in DoSomeThing();
           // can we throw some exception?
       }
       /* code to save the results in DB*/
   }
   

3. implementing it Fluent like :

   Foo x = new Foo();
   x.DoSomeThing().SaveSomething();
   

   in this case, it is important to guarantee that this is not happens:

   x.SaveSomething().DoSomeThing();
   

right now, i use the second method. is there any better way or is that enough?

Answer 1

One option to help avoid user error is to make it clear by passing a variable. By doing this, it raises a flag for the user that they need to get the results (i.e. DoSomething()) before calling SaveSomething(…).

results = DoSomething(); // returns the results to be saved
SaveSomething(results);