Few words on the 4th element of Simple Design

The 4 elements of Simple Design

Suggestions to young men

Few days ago I made an interview.
The interviewer (Tommaso Torti) asked me if I have suggestions to give to young men starting a new career in software development.
Just as a recap, I mentioned:

  • find a company with high skilled software developers
  • changing job frequently: for example every 2 years
  • after few experiences, remain a little bit longer (5 years?) to find how good your design decisions have been in the long term
  • read classics: not only about software design… I mean also The Mythical Man-Month by Fred Brooks, Peopleware by Tom DeMarco, etc…

A missing point

But I forgot to mention one of the most important point.
In my opinion, to become a real expert in Software Development (not only OOP), you have to spend a lot of time on the 4th element of Simple Design: minimal methods, classes and modules (also known as “fewest elements”).

I know it sounds silly: “ehi man, I am already writing the minimal methods, classes and modules!”
Maybe! But, maybe not!
How do I know?
2 reasons:

  1. I have seen code written by lots of people. Expert people. Very often, I could have written the same code with half of the objects/methods/modules maintaining (or even increasing) the readability of the entire code base
  2. I found people able to write the same code I wrote, with a reduced number of objects/methods/etc…

So yes, it is a virtuous “mechanism” that once established creates an “obsessive” research on “how to write less, keeping high readability”.

What happens in reality is that, Object Oriented Programmers are focused mainly on SOLID principles, on the first 3 elements of Simple Design and don’t give any attention to reduce the things they write.
This is the reason I wanted to say few words on the 4th element.

A story

I have a story to share with you.
In my company, we had a coding exercise as an entry test for every applicant: Sales Taxes (you can find my solution at that link).
As an interviewer, I have seen lots of solutions and I can tell you that the majority of applicants created a solution with more than 30 objects. Some of them, reached more than 50 objects. I remember one guy proposing a solution with more than 80 objects.
Few people used 10 objects or less.
I haven’t seen all solutions, so I am talking just about what I have seen.

Another aspect: some developers wrote a solution with lots of objects that could adhere perfectly to SOLID principles and to the first 3 elements of Simple Design. Other developers wrote with fewer elements, but with procedural code.
I can tell you this: I accepted solutions wrote by the latter more often than by the former.
The reason is that, it is very difficult to train yourself on writing less. I think it is almost impossible to train on production software without a mentor helping you, unless you are naturally “obsessed” on this topic.

It is all about “simplicity”

There is another reason I think the 4th element is important.
If you are an object oriented programmer, you are naturally inclined to organize “things” (objects, methods, etc…).
But, as mentioned in The Laws of Simplicity by John Maeda, there are a lot of other ways to create simplicity and the first one is called “REDUCE”.

How to improve

Assuming that you want to train yourself anyway without a mentor, I can share some “exercises” you can do in your daily job or in some pet project you have:

  • try to start with just one module: you can add more modules later. If you really need them (and probably they will be created with a different idea behind them)
  • try not to duplicate your domain objects due to your adapters.
    For example when you have a domain object and then you have another DTO for the REST adapter, one for the persistence, another one to call your supplier, etc…
    If you really need this solution, try to avoid at least a hierarchy of mappers to create those objects from domain ones and vice versa: put factory methods in those objects instead
    Anyway, did you try with just data mappers and Maps? Sometimes, the idea that you need another object lies only in your mind…
    Did you try using reflection with some project convention?
  • try to count the objects (or methods) you are creating for a new feature.
    Put a label near each one: NEEDED, MAYBE, USELESS
    – USELESS: you should delete them immediately
    – MAYBE: “maybe” you can do something to make them USELESS
    – NEEDED: maybe you can think again… once more… are you sure? If you really think they are NEEDED, leave them alone
  • avoid “extract method” to have then just a private method containing one call to a collaborator. It does not increase readability at all! Change the name of your collaborator instead (or of the method name called)
  • pay attention to Parameter Objects. The idea that you need a Parameter Object when you have more than n parameters is the most stupid thing I have ever read (if you think this call discount(Product, Price, MarketStrategy, Report) is less readable than discount(DiscountRequest) you’ll be in trouble reading my blog). Besides, Parameter Objects often hide domain objects in the primitives used (I wrote a story about this: check Once upon a time… in Objectsland).

If you want to share another training exercise, please write a comment below.

I hope you’ll find interesting to spend some time on this aspect of software design.

Once upon a time… in Objectsland

where only objects with a meaning are admitted

"Spiral Jetty" by Robert Smithson
“Spiral Jetty” by Robert Smithson

Once upon a time, there was a place called Objectsland.
Every day, objects were living their life, working together, forming new collaborations.
The city was continuosly growing and flurishing.

One day, Necromancer Techcoacho Ignoranto arrived in the city.
He had to deal with all the objects in the city.
Soon, he became scared. He didn’t want to deal with so intelligent objects.
He’d have want objects without a brain, so that he could control them.
The other objects would have not left him doing that, so, one night, he decided to cast a spell mentioned in ancient books of refactoring: “Parameter Objectorum!!!”

The day after, Objectsland seemed as before, but after few weeks new objects arrived… they were like buckets of texts, numbers, … and they were a lot… they were: the Parameter Objects! uhuhohohahahahahahah

One day, one of this Parameter Object was filled with a text girl called Airline and a boy called Flightnumber.
Airline was in love with Flightnumber, but she was just a lonely text and he was just… a number (e.g. 89)? or a text (e.g. “0089”)? he didn’t know…

Since the arrive of all those Parameter Objects, the life in Objectsland became difficult. You had to deal always with them for everything and they were so many that you didn’t know who was in charge of something.

One day, a mage arrived in Objectsland. He was called Oldoop Pragmatico.
Looking at the poor Airline walking alone far from Flightnumber, he decided to step in! Immediately, he cast the powerful spell: “Ubique Dominatum!!!”

Since then, no one has seen a Parameter Object.
Eventually, Airline married Flightnumber and they decided to form a family: they called themself FlightDesignator following the suggestion of IATA Guild.

All the free objects decided to put a signboard at the entrance of the city.
This is the message:

Welcome to Objectslands where only objects with a meaning are admitted.
For data buckets, DTOs, etc… please follow the other street.
It will lead you to Wasteland

A note for Software Engineers:
yes, I’m arguing that ParameterObject is an antipattern that will get you to MagicContainer sooner or later.
It’s just a matter of time.