C#, .NET, Java - General Naming and Coding Conventions

transcript

Complexity:A physician, a civil engineer, and a computer scientist were arguing about what was the oldest profession in the world.

The physician remarked, "Weil, in the Bible, it says that God created Eve from a rib taken out of Adam. This clearly required surgery, and so I can rightly claim that mine is the oldest profession in the world.

"The civil engineer interrupted, and said, "But even earlier in the book of Genesis, it states that God created the order of the heavens and the earth from out of the chaos. This was the first and certainly the most spectacular application of civil engineering. Therefore, fair doctor, you are wrong: mine is the oldest profession in the world.

"The computer scientist leaned back in her chair, smiled, and then said confidently, "Ah, but who do you think created the chaos?"

1From: Object-Oriented Analysis and Design with Applications by Grady Booch

Coding Standards -

Naming Conventions

Presented by Ashok GuduruTechnical Architect

Naming Conventions and Style

• Source code is a form of expression and so quality-of-expression must be a primary concern.

• Poor quality-of-expression creates ongoing costs

and impacts the productivity (hence the reputation) of the team that produces it.

• Therefore software authors must learn to clearly express the intention of variables, methods, classes, and modules.

What is the purpose of this (python) code?

list1 = []for x in theList:

if x[0] == 4:list1 += x;

return list1

Improved code…

flaggedCells = []for cell in theBoard:

if cell[STATUS_VALUE] == FLAGGED:flaggedCells += cell

return flaggedCells

Even more improved code…

flaggedCells = []for cell in theBoard:

if cell.isFlagged():flaggedCells += cell

return flaggedCells

public class ClientActivity{

public void ClearStatistics() {

//...}public void CalculateStatistics() {

//...}

• PascalCasing (a.k.a Proper Casing)– Use Pascal Casing for class/Type names and

method names

• camelCasing– Use camelCasing for method arguments and local

variables

public class UserLog{

public void Add(LogEvent logEvent){

int itemCount = logEvent.Items.Count;// ...

• Do not use Hungarian notation

// Correctint counter;string name;

// Avoidint iCounter;string strName;

• do not use Screaming Caps for constants or readonly variables

// Correctpublic static const string ShippingType = "DropShip";

// Avoidpublic static const string SHIPPINGTYPE = "DropShip";

• Avoid using Abbreviations. Exceptions: abbreviations commonly used as names, such as Id, Xml, Ftp, Uri

//CorrectUserGroup userGroup;Assignment employeeAssignment;

//AvoidUserGroup usrGrp;Assignment empAssignment; //ExceptionsCustomerId customerId;XmlDocument xmlDocument;FtpHelper ftpHelper;UriPart uriPart;

• use PascalCasing for abbreviations – 3 characters or more – 2 chars use both uppercase

HtmlHelper htmlHelper;FtpTransfer ftpTransfer;UIControl uiControl;

• do not use Underscores in identifiers. – Exception: You can prefix private static variables

with an underscore

//Correct

public DateTime ClientAppointment;

public TimeSpan TimeLeft;

//Avoid

public DateTime Client_Appointment;

public TimeSpan Time_Left;

//Exception

private DateTime _registrationDate;

• Use predefined type names instead of system type names like Int16, Single, UInt64, etc.

//Correct

string firstName;

int lastIndex;

bool isSaved;

//Avoid

String firstName;

Int32 lastIndex;

Boolean isSaved;

• use implicit type var for local variable declarations.

Exception: primitive types (int, string, double, etc) use predefined names.

var stream = File.Create(path);

var customers = new Dictionary<int?, Customer>();

//Exceptions

int index = 100;

string timeSheet;

bool isCompleted;

Procedural code gets information then makes

decisions.

Object-oriented code tells objects to do things.

--Alec Sharp

• use noun or noun phrases to name a class

public class Employee

public class BusinessLocation

public class DocumentCollection

The above style distinguishes type names from methods, which are named with verb phrases.

• Use '-able' as a suffix for interfaces• Name interfaces with adjective phrases, or occasionally with nouns

or noun phrases

public interface IObservable

public interface ISerializable

//More Examples…

Enumerable, Printable, Drinkable, Shootable, Rotatable, Readable, Writable, Groupable

• Types (Classes and Structs) are made of members: methods, properties, events, constructors, and fields. The following sections describe guidelines for naming type members.

• Give methods names that are verbs or verb phrases.

public class String { public int CompareTo(...); public string[] Split(...); public string Trim();}

public static class Console{

public static void Write(string format, object arg0)public static void WriteLine(char value);public static void SetWindowSize(int width, int height);public static void SetWindowPosition(int left, int top);public static void ResetColor();public static Stream OpenStandardError(int bufferSize);

• Names of Properties: Unlike other members, properties should be given noun phrase or adjective names. That is because a property refers to data (object state), and the name of the property reflects that.

• Always use PascalCasing to name properties.

• DO name properties using a noun, noun phrase, or adjective.• DO NOT have properties that match the name of "Get"

methods as in the following example:

public string TextWriter { get {...} set {...} } public string GetTextWriter(int value) { ... }

This above pattern typically indicates that the property should really be a method.

• Names of Properties: Name the collection properties with a plural phrase describing the items in the collection instead of using a singular phrase followed by "List" or "Collection."

private static double[] _sizeBins;public ICollection Instruments { get; set; }public int[] Temperatures { get; set; }public string[] Operators { get; set; }public string[] SizeRanges { get; set; }public string[] TrendChartColumns { get; set; }public string[] SampleDateIntervals { get; set; }public string[] XYChartColumns { get; set; }

• Names of Properties: Name Boolean properties with an affirmative phrase (CanSeek instead of CantSeek). Optionally, you can also prefix Boolean properties with "Is," "Can," or "Has," but only where it adds value.

Public class Stream{

public bool CanSeek { get {...} set {...} }public bool IsOpen { get {...} set {...} }public bool IsModifiable { get {...} set

{...} }public bool AllowChanges { get {...} set

{...} }public bool HasPassed { get {...} set {...} }public bool IsWritable { get {...} set {...} }public bool CanModify { get {...} set {...} }

• Names of Properties: CONSIDER giving a property the same name as its type.– For example, the following property correctly gets and sets an enum

value named Color, so the property is named Color:

public enum Color {...}

public class Control { public Color Color { get {...} set {...} }}

• Name source files according to their main classes. Exceptions: file names with partial classes reflect their source or purpose, e.g. designer, generated, etc.

//Located in Task.cspublic partial class Task{ //...}

//Located in Task.generated.cspublic partial class Task{ //...}

• Use one file per type (class, interface, enum, delegate, struct, event, attribute, exception etc.)

• Organize namespaces with a clearly defined structure.

// Examplesnamespace Company.Product.Module.SubModulenamespace Product.Module.Componentnamespace Product.Layer.Module.Group

• vertically align curly brackets.// Correctclass Program{

static void Main(string[] args) {

• declare all member variables at the top of a class, with static variables at the very top.

public class Account{

public static string BankName;public static decimal Reserves;public string Number {get; set;}public DateTime DateOpened {get; set;}public DateTime DateClosed {get; set;}public decimal Balance {get; set;}

// Constructorpublic Account(){

// ...}

• Use singular names for enums • Use plurals for bit field (Flagged) enums

public enum Color{

Red, Green, Blue, Yellow,Magenta,Cyan

[Flags]public enum Dockings{

None = 0, Top = 1, Right = 2, Bottom = 4, Left = 8

• do not explicitly specify a type of an enum or values of enums (except bit fields)

// Don'tpublic enum Direction: long{

North = 1,East = 2,South = 3,West = 4

// Correctpublic enum Direction{

North, East,South,West

• do notsuffix enum names with Enum

//Don'tpublic enum CoinEnum{

Penny,Nickel,Dime,Quarter,Dollar

// Correctpublic enum Coin{ Penny,

Nickel,Dime,Quarter,Dollar

• do notsuffix enum names with Enum

//Don'tpublic enum CoinEnum{

Penny,Nickel,Dime,Quarter,Dollar

// Correctpublic enum Coin{ Penny,

Nickel,Dime,Quarter,Dollar

• Some examples of BAD varibale names

int Cutomer_Name;int CustName;int CSTMR-NM;int empName;int intDrvrCde;int drvrcode;int d; //elapsed time in daysint tempId; //not sure Temperature or Template

String logininfoJSON

• Some examples of GOOD varibale names

int elapsedTimeInDays;int daysSinceCreation;int daysSinceModification;int fileAgeInDays;

• Identify the problems in the following code

public class MenuItem{ public int MenuID { get; set; }

//Manu Details public List<System.Web.Mvc.SelectListItem> Category { get; set; } public string Alerts { get; set; } public bool IsSKU { get; set; } public bool IsDirectOrderable { get; set; }

//Restaurant Details public List<System.Web.Mvc.SelectListItem> Restaurant { get; set; } public List<System.Web.Mvc.SelectListItem> AvailableTime { get; set; } public DateTime AvailableFrom { get; set; } public DateTime AvailableTo { get; set; }

//Price Details public double Price { get; set; }

//Add-on details public bool IsAddonSelectMandatory { get; set; } public List<System.Web.Mvc.SelectListItem> AddonType { get; set; } public List<System.Web.Mvc.SelectListItem> Addon { get; set; } public string RecipeDescription { get; set; }

public List<MenuItem> MenuItems { get; set; }}

• Identify the problems in the following code

public class ItemCategory{

public string CategoryName { get; set; } public string CategoryDescription { get; set; }}

When a tester didn't find any cool bugs, then he basically has two options to think about.

a) The software is good enough to go liveb) The software wasn't tested well enough

Typically, the developer thinks it is "a". And, of course, the tester always fears it could be option "b".

Thank you!

To be Contd…

You have to experience what you want to express

-- Vincent van Gogh

Ashok GuduruBlog: http://www.ashokg.com

Twitter: @AshokGudurc

C#, .NET, Java - General Naming and Coding Conventions

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