Coding Blocks Podcast (programming)

We continue talking our way through Clean Code, taking a deep look at the building blocks of programming in the quest to write the best functions. Oh, and everybody sings.

The original version of the show notes can be found at:
http://www.codingblocks.net/episode48

Direct download: coding-blocks-episode-048.mp3
Category:programming -- posted at: 8:40pm EDT

Command, Repository and Mediator Design Patterns

In this episode we go back to the design pattern well that we've been away from for so long.  We cover the Command, Repository and Mediator design patterns.  It was hard for us to believe, but it's been almost a year since our last design patterns episode!!!  Come on in for fun, learning, and of course, our tips of the week.

See the original show notes at:
http://www.codingblocks.net/epsiode42

Leave us a review here:
http://www.codingblocks.net/review

News

Stitcher Reviews:

Spectre013, Christoffer, Genius, HAM3rtag, joe_recursion_joe, Gearhead2k, Manriquey2k, Mike North, AndrewM, MildManneredCalvin, Freeleeks

iTunes Reviews:

Sid Savara, J. Mair, tonicorb, Nmkel999, Eschwartz20, mochadwi, Banjammin, wisco_cmo, NewZeroRiot, Nate_the_DBA, Pauloispaulo

Joe’s chess game!

Joe on Hello Tech Pros

Software Engineering Radio #256 on Unit Testing

!important is a CSS code smell.

Do you name your IIFEs? You should.

This is our 5th, Design Patterns Episode. Last one was in July 2015.

30: Adapter, Facade, and Memento
19: Iterators, Observers, and Chains
16: Strategy, Template, Null Object
11: Factories, Factory Methods, Builder, Prototype

What type of development do you prefer?

Front-End
Back-End
Full Stack

Design Patterns - Command, Repository, and Mediator

Command Pattern

  • Encapsulate a request as an object, thereby letting you parameterize clients with different requests, queue or log requests, and support undo.
  • It's not "method()" it's "new Object(), and later...object.invoke()
  • Why? Nice, clean way of organizing your code. Especially if….
  • OO replacement for callbacks - meh
    • Specify, queue, execute
    • Undo
    • Transactions/Logging
    • Not mentioned:
      • Macros
      • Async
  • Real World Applications
    • GUI/Menus - copy/paste/undo/photoshop
    • Video Games
      • Age of Empires sent commands rather than the game state!
      • It’s not if("B") { jump(); }, if(input[k]) { input[k].invoke() }
        • Great for different contexts, like menus
    • Parallel / Tasks
      • Async/Await
    • Queues / Multi-Step Wizards
      • Queue up the commands, execute all at once
    • Restaurants????
  • How it’s done:
    • Client: Customer
    • Receiver: Waiter
    • I/Command: Order
    • Invoker: Cook
  • Great example on sourcemaking.com
  • What about callbacks?
  • Why not the observer pattern?
  • Challenge for the listeners, program the command pattern - do it “by the book”

Repository Pattern

Why?

  • Testable with isolated data layer
  • Centrally managed access rules and logic
  • Centralized caching strategy
  • Allows you to separate business logic from data access logic
  • Strongly typed entities
  • Business entity associations
  • Can apply a domain model to simplify business logic
  • Decouple business entity from data storage technology - the repository doesn’t expose where it gets its data

What?

  • Sits between the data source and the business layer
    • Maps data from the data source to an entity
    • Persists changes from the entity back to the data source
      • Can use the Unit of Work pattern for complex, multi-step operations
    • Typically utilizes a Data Mapper Pattern, or an ORM such as Entity Framework in .NET

Mediator Pattern

What is it?

  • The mediator pattern defines an object that encapsulates how a set of objects interact
  • Promotes loose coupling by keeping objects from referring to each other explicitly
  • Promotes the Single Responsibility Principle by allowing communication to be offloaded to a class that handles just that.
  • Similar to the Observer pattern
    • Mediator pattern can be implemented during the observer pattern,
    • The Observer pattern distributes communication by introducing “observer” and “subject” objects.
  • Also similar to the Facade pattern in that it abstracts functionality of the classes.

Examples

  • Chat room
  • Air Traffic Control
  • Button events?

Resources We Like

http://gameprogrammingpatterns.com/
https://msdn.microsoft.com/en-us/library/ff649690.aspx?f=255&MSPPError=-2147217396
https://genericunitofworkandrepositories.codeplex.com/
http://blog.falafel.com/implement-step-step-generic-repository-pattern-c/
http://www.gamasutra.com/view/feature/131503/1500_archers_on_a_288_network_.php
https://sourcemaking.com/design_patterns/command
https://sourcemaking.com/design-patterns-book
http://www.codeproject.com/Articles/526874/Repository-pattern-done-right
https://en.wikipedia.org/wiki/Mediator_pattern
https://sourcemaking.com/design_patterns/mediator
http://programmers.stackexchange.com/questions/134432/mediator-vs-observer

Tips of this Episode

Allen:

Want a JavaScript tip per day?!
http://www.jstips.co/

Bonus!!!  Want tons of cheap stuff?!
App called "Geek" - download it on iOS or Android

Michael:

Use Nunit's TestCaseSource to test objects in your test cases

How to delete/forget about a wireless network in Win8.1

  • netsh wlan show profiles
  • netsh wlan delete profile name="gogoinflight"

SOURCE: http://www.digitalcitizen.life/how-delete-forget-wireless-network-profiles-windows-81

Joe:

Learn a new language! Stretch the brain, learn new concepts and see old concepts in a new light! Scripting, Compiled, Functional - Conway’s Game of Life!

Direct download: coding-blocks-episode-042.mp3
Category:programming -- posted at: 11:49pm EDT

How to be an Intermediate Programmer

Link to Episode 39's Full Show Notes
http://www.codingblocks.net/episode39

T-Shirt Giveaway - The winner is...
Manrique Logan - please contact us to send us your ship-to information!

This Episode's Survey
Suggested by: https://twitter.com/CatcheNameHere/status/700507429390274560

Princess rap battle: GALADRIEL vs LEIA
https://www.youtube.com/watch?v=RL52R7m8b7w

How to be an Intermediate Programmer

Personal Skills

Team Skills

Judgement

Resources We Like

How to be a Programmer: A Short, Comprehensive, and Personal Summary by Robert L Read
Make a Pull Request to get your thoughts in here:
https://github.com/RobertLRead/HowToBeAProgrammer
Or buy your copy here from Amazon:
http://amzn.to/1WzbIxs

Succinctness is Power - Paul Graham
http://www.paulgraham.com/power.html

You Don't Know JS
https://github.com/getify/You-Dont-Know-JS/blob/master/README.md

Want to know how fast you type?
http://www.typingtest.com/

Allen's Typing Speed on the Microsoft Sculpt Ergonomic

Microsoft Sculpt Ergonomic Keyboard
Microsoft Sculpt Ergonomic Keyboard

http://www.typingtest.com/result.html?acc=100&nwpm=90&gwpm=90&ncpm=452&gcpm=452&dur=60&time=60&chksum=45213&unit=wpm&kh=998&td=null&err=0&hits=452

specflow - Binding business requirements to .NET code
http://www.specflow.org/

 

Tips for this Episode

Allen Underwood: Execution plan for a running query in Microsoft SQL Server
Preface: You can click a button in Microsoft SQL Server Management Studio (SSMS) to see the execution plan of a query to identify any performance problems.  The biggest issue with this is that if there's a query that NEVER returns, or takes an insanely long time to return, then you're stuck waiting for the query to finish.  This tip shows you how to find the ACTUAL (not estimated) query plan of the query that is actively running:

How To:

EXEC sp_who2 'active' -- Find the SPID of the query you're running

DECLARE @spid INT = 123 -- From above

SELECT EQP.query_plan, *
FROM sys.dm_exec_requests AS ER
   CROSS APPLY sys.dm_exec_query_plan(ER.plan_handle) AS EQP
WHERE ER.session_id = @spid

Once that bottom query runs, you'll be provided a link in the results grid that you can click to open up the graphical execution plan.

Michael Outlaw: Have Git ignore changes you make to a specific file like you didn't make the changes, but still have it be part of the tracked files in Git.
Preface: Let's say you have a connection string configuration file that you change to point to your local database.  That config file needs to be tracked in Git, but you don't want your changes to accidentally get committed and pushed up to the remote repo, then this command is for you.

How To:

git update-index /path/to/file --assume-unchanged

Joe Zack: Life Tip -  Pay attention to the warnings in your IDE.  It's easy to get used to seeing several warnings and ignoring them because they're not errors.  Eventually a new one that actually matters will show up and by ignoring it, you could be creating heartache for yourself.  If you can, resolve the warnings that are currently showing up so that if a new one surfaces, it'll jump out at you like a sore thumb.

Direct download: coding-blocks-episode-039.mp3
Category:programming -- posted at: 5:29pm EDT

Talking about the short book "How to be a Programmer", which covers a huge spectrum of important topics for developers of all levels.

Direct download: coding-blocks-episode-038.mp3
Category:programming -- posted at: 12:36am EDT

Welcome back to the dramatic conclusion of our discussion on the 12 factor app. This time we're talking dev/prod parity, logs, and admin processes. Oh, and Call of Duty!

Direct download: coding-blocks-episode-36.mp3
Category:programming -- posted at: 1:41pm EDT

So, how DO you persist hierarchical Data? We discuss two common solutions to this age-old problem: Adjacency Lists and Nested Set Models. Also, Build Atlanta, technical problems, multi-monitor vs ultra-wide, and utilizing gaming mice to up your game.

Direct download: coding-blocks-episode-028.mp3
Category:programming -- posted at: 6:27pm EDT

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