Quick Intro to Clean Coding

Quick intro to Clean Coding
Aleksey Drobnych
Java Trainer

● What is bad code
● What is good code
● Code smells
● Tests
● Refactoring
What this all about?

I knew one sales guy who predicted that programming languages and
programmers will disappear some time because of power of next gen
smart business wizards.
What is programm? This is just set of business receipts written with
maximal level of precision and detalisation. It's impossible to do using
human language. It's too flexible. We need to invent specific DSL for the
system. And OOP is one of possible ways for this purpose.
Foreword

if (this == null)
{
// Logic here
}

switch (number)
{
case 0: printf("0"); break;
}

public int m_otCalc() {
return iThsWkd * iThsRte +
(int) Math.round(0.5 * iThsRte *
Math.max(0, iThsWkd - 400)
);
}

https://gist.github.com/adrobnych/5183752

Path one
● Code that just works (that's easy, man!)
● More Code that just works (huh, we'll survive!)
● Mmmooorrreee CCoodeee thaaat j juust wooork s
● MMMmmmmmmmmmmm mmmmmmmmm
● Great Technical Debt
Two ways of Code

Path two
● Code that just works
● Tests
● Refinement (finally we've done this spike)
● Test
● More Code just enough for Test
● Refactoring
● Test
● More Code just enough for Test
● Refactoring
● look mum no hands!
Two ways of Code

● Code needs to work today just
once
Simplisity

● Code needs to be easy for
change forever
Ability to grow

● Big Upfront Design
● We have no time for tests
● Just do so as you did before
● Don't touch it until it works
Know your daemons

● Any code can be rewritten
● Tests are your safety belt
● Leave the campground cleaner
than you found it
Know your angels

Transparent: The consequence of change are visible and
predictable
Reasonable: The cost of adding a new feature is
proportional to its value
Usable: if you already wrote the code, you can reuse it
Exemplary: More code like this would be good for your
app
How to judge the goodness
of code

● Object Oriented Design Patterns
● Object Oriented Design Principles
● Knowledge of language and Libs
● Code Smells
● Tests
● Code Reviews
Clean Code Toolset

● Object Oriented Design Patterns
In software engineering, a design pattern is a general reusable solution to
a commonly occurring problem within a given context in software design. A
design pattern is not a finished design that can be transformed directly into
source or machine code. It is a description or template for how to solve a
problem that can be used in many different situations. Patterns are
formalized best practices that the programmer must implement themselves
in the application.Object-oriented design patterns typically show
relationships and interactions between classes or objects, without
specifying the final application classes or objects that are involved.
Clean Code Toolset

● Object Oriented Design Principles
In computer programming, SOLID (Single responsibility, Open-closed,
Liskov substitution, Interface segregation and Dependency inversion)
is a mnemonic acronym introduced by Michael Feathers for the "first five
principles" identified by Robert C. Martin in the early 2000s that stands for
five basic principles of object-oriented programming and design. The
principles when applied together intend to make it more likely that
aprogrammer will create a system that is easy to maintain and extend over
time.The principles of SOLID are guidelines that can be applied while
working on software to remove code smells by causing the programmer to
refactor the software's source code until it is both legible and extensible. It
is typically used with test-driven development, and is part of an overall
strategy of agile and adaptive programming.
Clean Code Toolset

● Knowledge of language and Libs
List of Efective Java units
Clean Code Toolset

● Code Smells
In computer programming, code smell is any symptom in the source code
of a program that possibly indicates a deeper problem. Code smells are
usually not bugs—they are not technically incorrect and don't currently
prevent the program from functioning. Instead, they indicate weaknesses in
design that may be slowing down development or increasing the risk of
bugs or failures in the future.
Clean Code Toolset

● Tests
Test-driven development (TDD) is a software development process that
relies on the repetition of a very short development cycle: first the
developer writes an (initially failing) automated test case that defines a
desired improvement or new function, then produces the minimum amount
of code to pass that test, and finally refactors the new code to acceptable
standards. Kent Beck, who is credited with having developed or
'rediscovered' the technique, stated in 2003 that TDD encourages simple
designs and inspires confidence.
Clean Code Toolset

● Code Reviews and refactorings
Code refactoring is a "disciplined technique for restructuring an existing
body of code, altering its internal structure without changing its external
behavior", undertaken in order to improve some of the nonfunctional
attributes of the software. Advantages include improved code readability
and reduced complexity to improve the maintainability of the source code,
as well as a more expressive internal architecture or object model to
improve extensibility.
Clean Code Toolset

Small refactorings way:
https://github.com/adrobnych/CleanCalc
Live refactoring session

Quick way: Patterns
Live refactoring session

Write tests.
If your Classes and Methods are just DSL of the
system, then tests is your first and most
important way to start talk with silent system.
Finally both your tests and the system will talk
Perfect Language.
Keep your tests as a grammar for your DSL.
From where I shall start?

Don't write comments.
85% of developer job is reading of existing code.
Keep your code readable, self-explanatory,
intentional. Comments are poor deodorant for
your code. If you will find yourself writing
comment then you can't express your intent in
code. This is smell. Refactor.
From where I shall start?

What's next?
Object Oriented Design
Effective Java
Clean Code, Code Smells, Refactorings
OOD Patterns
TDD
Crossroad

Quick Intro to Clean Coding

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