Best pattern/architecture for collecting data methods-CodePudding

I have a Java Spring batch step, which collets all the data for the next writing step. This controller message collects data from several datasources. After collecting, all the date is put into a result object which gets returned to the caller method. This is my pseudo code method:

public ReturnObject collectData() {
   List<A> a = getDataA();
   ...
   List<Z> z = get dataZ();
      
   ReturnObject o = new ReturnObject();
   o.setA(a);
   ...
   o.setZ(z);
   return o;
}

In this example it looks not so ugly, but I have to call about 15 of those methods and the method is grown very long.

Is there a better pattern to structure such a method.

I could do something like:

populateDataAIntoReturnObject(returnObject);

but this would hide the writing process into the return object in the sub-method.

Is there a better pattern for such data collecting methods?

CodePudding user response：

As mentioned it's hard to help you without a more complete idea of what you are doing. This beeing said I think populateDataAIntoReturnObject(returnObject) seems a bit worse than what you currently have. Returning a object instead of filling in a parameter gives you more control. You could for example cache objects in the future which isn't possible if you always need to create a new one to provide it as a parameter.

There are quiet a few patterns, that you could use (Repository, Service etc.), but they are more about hiding the implementation instead of structuring your code.

CodePudding user response：

You should rather create a public method populateData() within ReturnObject class which will set its own member variables. So code block will look like this.

  public class ReturnObject {
 ...
    public void populateData () {
        List<A> a = getDataA();
        ...
        List<Z> z = get dataZ();


        setA(a);
        ...
        setZ(z);

    }
    
}

And you can use the class like this

...
ReturnObject o = new ReturnObject();
o.populateData ();

CodePudding user response：

You can use Service-classes. One "head" service-class collects data from other services and represents it to controller