what is good code?

©2010 Improving Enterprises, Inc.

Good CodeWhat, Why, and How to Get There

Houston Java Group 2015

Jane Prusakova

Josh Rizzo

@Improving Enterprises College Station


What is “good”?

Functional

Bug-free

Performant

Good design

Tested

Testable

Easy to change

READABLE


Usability

Users and clients Developers


“Programs must be written for people to read, and only incidentally for machines to execute.”

– Abelson and Sussman


Readability has valueNOW

Code is an asset

affects productivity

monetary value

Readability has value OVER TIME

Software evolves over time

Work by many different teams

Changes affect value


Readability has cost

More hard work

More time

More training


How good code does not happen


Readable code

Easy to read

Has a narrative

UnambiguousWYSIWYG

Follows convention


It was hard to write

It should be hard to read

Who is responsible?


Lets make code more…

READABLE

See: https://github.com/joshrizzo/ReadabilityJava


Visible code

White space!

Spacing and indent matter

The Law of Demeter

– avoid the “train wreck” coding style

Step 1


Small stepsOne thing at a time

Glance-sized chunks

“Programming can be fun, so can cryptography; however they should not be combined.”

– Kreitzberg and Shneiderman

Step 2


Code with a narrativeUse naming to show intent

Testable code

“Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it.”

– Brian W. Kernighan

Step 3


Single Responsibility

Architecture

Interface design

"Good design adds value faster than it adds cost."

- Thomas C. Gale

Step 4


Easy to read

Single level of abstraction

“The purpose of abstraction is not to be vague, but to create a new semantic level in which one can be absolutely precise.”

– Edsger Dijkstra

Step 5


Readable++Simplicity


“Everything should be made as simple as possible, but not simpler.”

– Albert Einstein


Simple vs Fast

Correctness more important than speedSimple code is more likely to be and stay correct

Modularize code w/ performance concernsOptimize locally


Simple vs FlexibleRe-use is rare

Predictions of re-use are poor

Raises complexity significantly

Unused => not working


Simple vs Clever

Over engineering

Mixing abstractions

Inappropriate patterns

Complicated syntax


Good CodeWhat, Why, and How to Get There

https://github.com/joshrizzo/ReadabilityJava/

Houston Java Group 2015

Jane Prusakova

Josh Rizzo

@Improving Enterprises College Station