Top 5 ways to improve your code

Top 5 Ways to Improve YourCodeEric De CarufelAgile Coachhttp://blog.decarufel.nethttp://pyxis-tech.com

Introduction• Legacy code is code without tests • Michael Feather in Working effectively with legacy code• Without continuous maintenance the code will degrade rapidly• We need to detect and remove code smell

My Top 5 Improvements 1. Simplify conditionals 2. Improve code documentation 3. Improve method calls 4. Manage scope 5. Remove dead code

1. Simplify conditionals – Why?• Reduced complexity• Better readability• Better maintainability• Better reusability

1. Simplify conditionals –When?• There is more than one condition (and / or)• There is too much code in the body• The condition is based on type• There are nested if statements• There are many decisions based on the same info (if else if chain / switch case)

1. Simplify conditionals – How?• Refactor conditional statements • Decompose conditional code • Consolidate conditional expressions • Consolidate duplicate conditional fragments • Introduce null objects • Flatten nested if • Dont use negative conditions • Keep conditional statements lean• Avoid conditional statements • Replace conditional code with polymorphism • Replace conditional logic with strategy • Replace conditional dispatchers with commands

Decompose Conditional Code

Consolidate Conditional Expressions

Consolidate Duplicate Conditional Fragments

Introduce Null Objects

Flatten Nested if

Dont Use Negative Conditions

Keep Conditional Statements Lean• Do your best to have only one condition • Use methods to combine multiple conditions• Invert your conditions if most (or all) the code of your method is inside the "true" block • Make sure to avoid double negation

Replace Conditional with Polymorphism

Replace Conditional Logic with Strategy

Replace Conditional Dispatcher with Command

2. Delete comments – Why?• Better readability• Better maintainability• Fewer obsolete comments

2. Delete comments – When?• Every time there is a comment that is not (useful) information, intention, clarification, warning, TODO or amplification.• Comments are the only content of a code section • Empty catch statements• Your comments describe line by line what you are trying to do • Example: // Getting connection string from configuration // Opening connection // Retrieving data // Closing connection

2. Delete comments – How?• Replace comments with good naming • Extract methods • Use meaningful names• Write useful comments• Naming Conventions (MSDN: Guidelines for names) • Properties • Enums • Events • Methods

Extract Methods

Use Meaningful Names• Use Intention-Revealing names• Avoid disinformation• Make meaningful distinctions• Use pronounceable names• Avoid encoding• Avoid mental mapping• Class names -> nouns not verbs• Method names -> verbs• Dont be cute. Use standard names• Solution Domain Names vs Problem Domain Names

Properties• Do use PascalCase naming• Do name properties with a noun, noun phrase or an adjective• Do Not use names that match Get method• Do name booleans with Can, Is or Has prefix

Enums• Consider the first element to be the default value• Do use PascalCasing naming• Single choice enumerations should be singular• Bit fields enumerations should be plural and have Flags attibute• Value of bit fields enumeration should be coherent (Read & Write == ReadWrite)

Events• Do use PascalCase naming• Do name event using a verb, present progressive for pre-event and past for post-event• Do provide a virtual version of the event to override• Do provide a way to cancel pre-event

Methods• Do give methods names that are verbs or verb phrases • ProcessPayment• Do express the return value in method name • CreateCustomer • GetInvoice• Use consistent naming (Get, Fetch or Retrieve but not all in same context)

3. Clarify contracts – Why?• Better performance• Better readability• Better reusability

3. Clarify contracts – When?• There are too many parameters (how many is too many?)• A method does more than one thing• A method uses out parameters• You need default values

3. Clarify contracts – How?• Reduce number of parameters • Introduce parameter object • Create overloads with less parameters • Use default values• Function output • Return type value • Use out parameters• Overload methods in proper order

Introduce Parameter Object

Create Overloads with Fewer Parameters

Use Default Values

4. Reduce scope – Why?• Avoid side effects• Better reusability• Better maintainability

4. Reduce scope – When?• A field is used in only a few methods• Public members expose class behavior

4. Reduce scope – How?• Reduce visibility • Use protected • Use private • Use Internal• Reduce scope • Move fields to method • Split class • Move local variable close to its use• Reduce lifetime • Initialize late • Reduce references • Free early

5. Remove Dead Code – Why?• Because you must• Better maintainability• Better performance• Better readability• 100% test coverage

5.Remove Dead Code – When?• You know the code is dead• You think the code is dead• You want that code to be dead

5. Remove Dead Code – How?• Identify and remove dead code • Delete the code • Compile • Run the tests• What is dead code? • Commented code. • Any line of code that is not covered by unit tests.• Tools • There are tools that delete all code not covered by unit tests.

Next Steps• Improve your conditional code• Improve your documentation• Improve your method calls

Resources • Refactoring – Improving the design of existing code • Author: Martin Fowler • Edition: Addison Wesley • ISBN: 978-0-201-48567-7 • Refactoring to patterns (Martin Fowler signature) • Author: Joshua Kerievsky • Edition: Adison Wesley • ISBN: 978-0-321-21335-1 • Clean code – a handbook of agile software craftsmanship • Author: Robert C. Martin • Edition: Prentice Hall • ISBN: 978-0-132-35088-4 • Working effectively with legacy code • Author: Michael C. Feather • Edition: Prentice Hall • ISBN: 978-0-13-117705-5

Related sessions• Day 2 – 08h45 to 10h00 • DEV373 – Testing with Microsoft Visuals Studio Test Professional and the new Team Lab 2010 by Etienne Tremblay• Day 2 – 10h30 to 11h45 • ARC301 – Design by Contract (DbC) and Code Contracts in Visual Studio 2010 by Joel Hebert

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© 2011 Microsoft Corporation. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries.The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.

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Top 5 ways to improve your code

by Eric De Carufel on Nov 29, 2011

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Top 5 ways to improve your code — Presentation Transcript