KE
  • dotNet Web 3.0
  • Engineering Management
    • Process Planning (SDLC)
      • Software development process
      • Basics of SDLC models
      • Scrum
      • Kanban
      • Scrum vs Kanban: applicability
      • Scrumban
    • Estimation
      • Scope Concept
      • Estimates, Targets, and Commitments
      • Overestimate vs Underestimate
      • Decomposition and Recomposition
      • Analogy-based estimations
      • Estimating in Agile
  • Requirements
    • Software Requirements Engineering
      • Requirement definition
      • Levels of Requirements
      • Most common requirements risks
      • Characteristics of Excellent Requirements
      • Benefits from a High-Quality Requirements Process
      • Root Causes of Project Success and Failure
  • Design
    • OOD
      • Abstraction
      • Encapsulation
      • Inheritance vs Aggregation
      • Modularity
      • Polymorphism
      • Abstraction Qualities (cohesion, coupling, etc)
      • Types vs. Classes
      • Separation of concerns principle
      • SOLID
      • Design Patterns
        • Structural patterns
        • Creational patterns
        • Behavioral patterns
      • Most often used design patterns
      • Software Architecture Patterns (structure, pros & cons)
      • Inversion of Control Containers and the Dependency Injection pattern
      • Domain-Driven Design patterns
      • Anti-patterns
    • DB Design
      • Relational Terminology: Entities
      • Relational terminology: Attributes
      • Relational terminology: Records (Tuples)
      • Relationships (One-to-One, One-to-Many)
      • Understanding ER notation
      • Understanding normalization concept
      • Data Integrity
    • Modeling
      • UML: Basic Diagram Types
      • UML: Use Case Diagram (Essentials)
      • UML: Class Diagram (Essentials)
      • Entity Relationship Diagrams
      • Data Flow Diagrams
    • Security
      • Information security concepts
      • Access Control Lists (ACLs)
      • Access Control Models
      • .NET Cryptography Model
      • ASP.NET Identity
      • OWASP Top 10
      • Cross-Site Request Forgery (XSRF)
      • Protecting against cross-site scripting attacks (XSS)
      • Protecting against buffer overrun attacks
      • Protecting against SQL-injection attacks
      • CSRF/XSRF protection
    • Algorithms
      • Algorithms complexity (understanding, big O notation, complexity of common algorithms)
      • Array sorting methods (bubble sort, quick sort, merge sort)
      • Tree structure (construction, traversal)
      • Binary search algorithm
      • Hash table (creating, collisions)
      • Stack, queue, linked list (construction, understanding, usage)
  • Construction Core
    • Programming language
      • Declare namespaces, classes, interfaces, static and instance class members
      • Types casting
      • Value and reference types. Class vs Struct usage.
      • Properties and automatic properties
      • Structured Exception Handling, Exception filters
      • Collections and Generics
      • Dictionaries. Comparison of Dictionaries
      • Building enumerable types
      • Building cloneable objects
      • Building comparable types
      • Nullable types
      • Delegates, events and lambdas
      • Indexers and operator overloading
      • Anonymous types
      • Extension methods. Practices.
      • Custom Type Conversions (implicit/explicit keywords)
      • Strings and StringBuilder. String concatenation practices. String Interpolation
      • Serialization
      • System.IO namespace
      • LINQ to Objects
      • General Coding conventions for C#
      • Static Using Statement
      • Type Reflection
      • Custom attributes
      • Dispose and Finalizable patterns
      • Garbage collection
      • .Net Diagnostics
      • Implementing logging
      • Exception handling guidelines
      • Regular Expressions
      • Span<T> struct
      • C# - What's new?
      • .NET Standard overview
    • Concurrency
      • Understand differences between Concurrency vs Multi-threading vs Asynchronous
      • Concurrency: An Overview
      • Async basics
      • Task Parallelism
      • Basic Synchronization in C#
      • Deadlock problem
      • QueueBackgroundWorkItem or IHostedService for .NET Core
      • How to run Background Tasks in ASP.NET
    • Refactoring
      • Refactoring Concept (what/when/why)
      • Smells Catalog and possible re-factorings
      • Moving Features Between Objects (basic)
      • Organizing Data (basic)
      • Composing Methods (basic)
      • Simplifying Conditional Expressions (basic)
      • Making Method Calls Simpler
      • Dealing with Generalization
    • Product deploying, software installation
      • Create, configure, and publish a web package (.NET Web Profile)
      • Publishing Web Services
      • Manage packages by using NuGet, NPM and Bower
    • Networking
      • Understanding networks: layers and protocols
      • Basic understanding of TCP/IP model and protocols
      • Defining internet, intranet and VPN
      • Basics of Firewalls and DMZ
      • Application layer protocols basics (HTTP, FTP, Telnet)
      • Understanding HTTP and WWW
      • Basic troubleshooting tools (ICMP, ping, traceroute)
      • Client/Server model
      • Sockets, IP and port addressing
      • Using proxy server
      • File transfer services: FTP, TFTP
      • Name resolution services: DNS, whois
      • Remote access services: Telnet, SSH, rdesktop, VNC
      • The basic difference between HTTP and HTTPS protocols
  • Construction Web
    • Web server applications
      • ASP.NET Core
        • Application startup
        • Middleware
        • Working with Static Files
        • Routing
        • Error Handling
        • Globalization and localization
        • Configuration
        • Logging
        • File Providers
        • Dependency Injection
        • Working with Multiple Environments
        • Hosting
        • Managing Application State
        • Request Features
      • ASP.NET Core MVC
        • MVC basics (Model, View, Controller, DI)
        • Model binding and validation
        • View (Razor compilation, Layout, Tag Helpers, Partial Views, DI, View components)
        • Controllers (Route to actions, File uploads)
      • Security and Identity (concepts understanding)
        • Authentication
        • Using identity
        • Authorization with roles
      • Bundle and Minify assets
      • Develop ASP.NET Core MVC apps
      • Advanced topics for ASP.NET Core MVC
        • Application model
        • Filters
        • Areas
        • Application Parts
        • Custom Model Building
        • IActionConstraint
      • Host and deploy ASP.NET Core
      • Migrate from ASP.NET to ASP.NET Core
      • Troubleshoot ASP.NET Core projects
      • Open Web Interface for .NET (OWIN)
      • Web server implementations in ASP.NET Core
    • Web Services
      • REST
      • ASP.NET Web API
        • Routing
        • Configuration
        • Basic error handling
      • Web API-based services
      • Web API Security
      • Token based security
      • SingalR
      • Serialization Frameworks
      • Implement caching
      • gRPC on ASP.NET Core
      • API versioning
      • API documentation
    • Microservices and Cloud
      • Microservices architecture
      • Dockerize a .NET Core application
      • Development workflow for Docker apps
    • JavaScript, HTML, CSS
      • JavaScript: Variables
      • JavaScript: Data types and types conversion
      • JavaScript: Operators
      • JavaScript: Control and Loop constructions
      • JavaScript: Functions, Execution Context and Variables scopes
      • JavaScript: Arrays
      • JavaScript: JS in WebBrowser and basic DOM manipulations
      • HTML: Basic elements
      • CSS: Simple Style rules
      • CSS: selectors
      • Box model
      • HTML: Standards and Browser compatibility
      • HTML: Page Layouts with divs
      • HTML: Frames
      • CSS: Elements positioning and layering
      • CSS: Tables properties
      • CSS: Flexbox
      • Different storage
      • JavaScript: Event Understanding (propagation, capturing, attach/detach)
      • JavaScript: Closure
      • AJAX/JSON
      • Ecma script 6: OOP
      • Promise
      • Strict mode of javascript
    • JavaScript Frameworks
      • Selecting elements
      • Operating on collection
      • Manipulating with elements, working with properties, attributes and data
      • Events
      • animation and effects
      • utilities and Ajax
      • SPA (SINGLE PAGE APPLICATIONS)
      • EcmaScript 6
      • UI frameworks basics:
      • NPM basics:
      • React basics
  • Construction DB
    • SQL
      • Tables, relationships, keys, constraints understanding
      • DDL, DML, DCL understanding
      • SQL data types
      • SQL operators, functions
      • Data manipulation (insert, update, delete)
      • Retrieving data (simple select statement)
      • Joins understanding
      • Creating, modifying, removing database objects
      • Aggregations (ORDER BY, GROUP BY, HAVING, SUM, COUNT, AVG, etc)
      • Combining the results of multiple queries (UNION, EXCEPT, INTERSECT, MINUS, subqueries)
      • Sessions, transactions, locks
      • Isolation levels understanding
      • Implementing stored procedures, user-defined functions, triggers
      • Cursors
    • Data Access Layer
      • Manage connection strings and objects
      • Working with data providers
      • Connect to a data source by using a generic data access interface
      • Handle and diagnose database connection exceptions
      • Manage exceptions when selecting, modifying data
      • Build command objects and query data from data sources
      • Retrieve data source by using the DataReader
      • Manage data by using the DataAdapter and TableAdapter
      • Updating data
      • Entity Framework
        • Query data sources by using EF
        • Code First to existing DB
        • Entity Data Modeling Fundamentals
        • Querying Data
        • Data modification
  • Verification
    • Code Quality
      • MSDN: Guidelines for Names
      • SDO Best Practices Catalog - Coding Standards
      • SDO Best Practices Catalog - Code Review Process
      • SDO Best Practices Catalog - Automatic Code Inspection
      • Automated coding standards enforcement (StyleCop, Resharper)
      • Code Reviews and Toolset
      • Use Work Items (TODO, BUG etc.)
      • Preemptive Error Detection
      • Desirable characteristics of a design (minimal complexity, ease of maintenance, minimal connectednes
      • Creating high quality classes
      • Creating high quality methods
      • Guidelines for initializing variables
      • Exceptions and error handling techniques
      • Best practices of working with data types
      • Code commenting practices
    • Automated Testing (principles, patterns, and practices)
      • Software testing basic concepts
      • Software testing concept
      • Test Case
      • Test Suite
      • Test Plan
      • Testing Levels
      • Naming standards for unit tests
      • Types of test doubles (Stub, Mock, Spy, Fake, Dummy)
      • Basic coverage criteria
      • Testing concepts (Unit vs Functional vs Integration)
      • Goals of Unit Testing, What Makes a Test Valuable?
      • Styles of Unit Testing (Output / State / Collaboration)
      • Good unit test properties
      • F.I.R.S.T Principles of unit testing
      • Test Pyramid concept
      • Testing Pyramid, Agile Testing Pyramid, Diamond
      • Breaking the dependency, Interaction testing
      • Strategies for isolating the database in tests
      • Test smells and how to avoid
      • Test Organization patterns
      • Fixture setup patterns
      • Test double patterns
      • Feature-driven development (FDD)
      • Behavior-driven development (BDD)
      • Test-driven development (TDD)
      • Acceptance testing, Acceptance Test Driven Development (ATDD)
      • Continuous testing
    • Automated Testing (Frameworks, Tools, Libraries)
      • .NET unit test frameworks overview
      • .NET Mocking Frameworks, a comparison
      • xUnit
        • Primary test framework attributes
        • Asserts
        • Exception Handling in Unit Tests
        • Skipping Tests
        • Initialization and Cleanup (Assembly, Class, Test)
        • Data-driven Tests
      • NSubstitute
        • Mocking Method Calls (Using Mock Object, Return Values, Argument Matching)
        • Behavior Verification (Method Was/Not Called, a Specific Number of Times, Getter/Setter Was Called)
        • Throwing exceptions
        • Raising Events from Mock Objects
        • Returning Different Results for Sequential Calls
      • AutoFixture
      • EF Core InMemory test
      • Integration tests in ASP.NET Core
      • Isolating database data in integration tests
      • Test ASP.NET Core MVC apps
  • Configuration Management
    • Product builds and Continuous Integration
      • Automated build concept
      • Dotnet cli
      • CI/CD Basic concepts
    • Managing Versions
      • Fundamental concepts: revisions, working copy, repository, branch, baseline, trunk
      • Versioning Models
      • Distributed Version Control basics
      • Distributed systems advantages and weak sides
      • VCS Management life-cycle on (one of) major tools (clone, commit, update, revert, merge, resolve, et
      • Branching/Merging strategies
      • Blaming (annotate)
      • Revision graph/log actions (Git)
      • Integrating with Issue Tracking Systems
      • Source control Best Practices
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On this page
  • Extract Method
  • Inline Method
  • Inline Temp
  • Replace Temp with Query
  • Split Temporary Variable
  1. Construction Core
  2. Refactoring

Composing Methods (basic)

Extract Method

Extract Function is one of the most common refactorings.

If you have to spend effort looking at a fragment of code and figuring out what it’s doing, then you should extract it into a function and name the function after the “what.” Then, when you read it again, the purpose of the function leaps right out at you, and most of the time you won’t need to care about how the function fulfills its purpose (which is the body of the function).

Mechanics

  • Create a new function, and name it after the intent of the function (name it by what it does, not by how it does it).

  • Copy the extracted code from the source function into the new target function.

  • Scan the extracted code for references to any variables that are local in scope to the source function and will not be in scope for the extracted function. Pass them as parameters.

  • Compile after all variables are dealt with.

  • Replace the extracted code in the source function with a call to the target function.

  • Test.

  • Look for other code that’s the same or similar to the code just extracted, and consider using Replace Inline Code with Function Call to call the new function.

Inline Method

this is inverse of: Extract Method

One of the themes of this book is using short functions named to show their intent, because these functions lead to clearer and easier to read code. But sometimes, I do come across a function in which the body is as clear as the name. Or, I refactor the body of the code into something that is just as clear as the name. When this happens, I get rid of the function. Indirection can be helpful, but needless indirection is irritating.

I also use Inline Function is when I have a group of functions that seem badly factored. I can inline them all into one big function and then reextract the functions the way I prefer.

I commonly use Inline Function when I see code that’s using too much indirection — when it seems that every function does simple delegation to another function, and I get lost in all the delegation. Some of this indirection may be worthwhile, but not all of it. By inlining, I can flush out the useful ones and eliminate the rest.

Mechanics

  • Check that this isn’t a polymorphic method

  • If this is a method in a class, and has subclasses that override it, then I can’t inline it

  • Find all the callers of the function

  • Replace each call with the function’s body

  • Test after each replacement

  • Remove the function definition

Inline Temp

Variables provide names for expressions within a function, and as such they are usually a Good Thing. But sometimes, the name doesn’t really communicate more than the expression itself. At other times, you may find that a variable gets in the way of refactoring the neighboring code. In these cases, it can be useful to inline the variable.

Mechanics

  • Check that the righthand side of the assignment is free of side effects

  • If the variable isn’t already declared immutable, do so and test

  • This checks that it’s only assigned to once

  • Find the first reference to the variable and replace it with the righthand side of the assignment

  • Test

  • Repeat replacing references to the variable until you’ve replaced all of them

  • Remove the declaration and assignment of the variable

  • Test

Replace Temp with Query

Using functions instead of variables also allows me to avoid duplicating the calculation logic in similar functions. Whenever I see variables calculated in the same way in different places, I look to turn them into a single function.

Only some temporary variables are suitable for Replace Temp with Query. The variable needs to be calculated once and then only be read afterwards. In the simplest case, this means the variable is assigned to once, but it’s also possible to have several assignments in a more complicated lump of code—all of which has to be extracted into the query.

Furthermore, the logic used to calculate the variable must yield the same result when the variable is used later—which rules out variables used as snapshots with names like oldAddress.

Mechanics

  • Check that the variable is determined entirely before it’s used, and the code that calculates it does not yield a different value whenever it is used

  • If the variable isn’t readonly, and can be made readonly, do so

  • Test

  • Extract the assignment of the variable into a function

  • Test

  • Use Inline Variable to remove the temp

Split Temporary Variable

You have a temporary variable assigned to more than once, but is not a loop variable nor a collecting temporary variable. Make a separate temporary variable for each assignment.

Temporary variables are made for various uses. Some of these uses naturally lead to the temp's being assigned to several times. Loop variables [Beck] change for each run around a loop (such as the i in for (int i=0; i<10; i++). Collecting temporary variables [Beck] collect together some value that is built up during the method.

Many other temporaries are used to hold the result of a long-winded bit of code for easy reference later. These kinds of variables should be set only once. That they are set more than once is a sign that they have more than one responsibility within the method. Any variable with more than one responsibility should be replaced with a temp for each responsibility. Using a temp for two different things is very confusing for the reader.

Mechanics

  • Change the name of a temp at its declaration and its first assignment.

  • Declare the new temp as final.

  • Change all references of the temp up to its second assignment.

  • Declare the temp at its second assignment.

  • Compile and test.

  • Repeat in stages, each stage renaming at the declaration, and changing references until the next assignment.

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Last updated 5 years ago