Guru Stop

Microsoft has released a final version of its book “Microsoft Application Architecture Guide, 2nd Edition”.

The book is described as:

This guide is available online here in the MSDN Library and will be available in the Fall of 2009 as a Microsoft Press book, ISBN# 9780735627109, that you can purchase through local and online booksellers.

The guide is intended to help developers and solution architects design and build effective, high quality applications using the Microsoft platform and the .NET Framework more quickly and with less risk; it provides guidance for using architecture principles, design principles, and patterns that are tried and trusted. The guidance is presented in sections that correspond to major architecture and design focus points. It is designed to be used as a reference resource or to be read from beginning to end.

The guide helps you to:

• Understand the underlying architecture and design principles and patterns for developing successful solutions on the Microsoft platform and the .NET Framework.
• Identify appropriate strategies and design patterns that will help you design your solution's layers, components, and services.
• Identify and address the key engineering decision points for your solution.
• Identify and address the key quality attributes and crosscutting concerns for your solution.
• Create a candidate baseline architecture for your solution.
• Choose the right technologies for your solution.
• Identify patterns & practices solution assets and further guidance that will help you to implement your solution.

 

More information about the book in this blog post:

http://blogs.msdn.com/jmeier/archive/2009/11/05/now-available-patterns-practices-application-architecture-book.aspx

The book is:

Available for online reading at:

http://msdn.microsoft.com/en-us/library/dd673617.aspx

Available for free download (PDF Format) at:

http://www.codeplex.com/AppArchGuide/Release/ProjectReleases.aspx?ReleaseId=20586

Available in print (to buy hard copy) from Amazon at:

http://www.amazon.com/Microsoft%C2%AE-Application-Architecture-Patterns-Practices/dp/073562710X

Have fun reading,

While I was planning to write about the same topic and have the draft ready in my Windows Live Writer waiting to complete, I found an interesting question in StackOVerflow and couldn’t just resist to answer:

ORM/Persistence layer Advice

The question starts with:

I'm starting a new project and I'm looking around for either a very good ORM or for a non-SQL-based persistence layer.

Then follows up with a REALLY GOOD summary of what he believes about each known ORM he knew out of his own findings and search. I advice you to go read it.

However, all this investigation didn’t get him to a single choice answer. And I can’t blame him. This is one fo the questions that will remain for so long without a single answer, or maybe having the popular “It depends” answer.

I have had a LONG research in this topic as well. I have read for so long (and watched videos/casts) to make sure of the best usage of many ORMs and then used them sometimes in test projects sometimes in production, and I wanted to share my thoughts based on this. I posted a long answer there on the question in StackOverflow, and I want to share this answer with you here. I may also have a second part of this post based on my existing Windows Live Writer draft, but, based on my previous times, I think I won’t!

Let me first quote some parts from the question itself:

I also want to avoid at all cost having to mess with string-based queries so tools supporting LINQ or otherwise intuitive and possibly strongly typed queries get a big bonus.
Finally working with POCO objects is another thing I'd really want to do
Here's a list of products I've evaluated and why they don't fit, just so that I don't see any advice about using those:

NHibernate: crazy xml stuff, too much set up, high maintenance complexity and cost for model changes, session factories are messy and don't fit well with my needs

Castle ActiveRecord: NHibernate based, little documentation plus some problems related to NHibernate still apply. Furthermore, to get decent models it takes so many attributes that one is better off creating the schema manually, and the way relations are handled is a shame.

Linq To SQL: missing POCO objects and according to MS it won't improve much overtime (EF is what they're committed to)

Entity Framweork: although in v4 POCO objects are possible, they're still pretty hacky and force you into doing too much manual work to set things up. Besides, v4 is just a beta

LLBLGen Pro: good, especially with SelfServicing adapters, but not POCO. Also, the LINQ provider isn't perfect yet. Finally, deleting a group of objects is not possible via LINQ which results in mixing APIs (one of which is far from intuitive) and that I don't like.

SubSonic SimpleRepository: for a few minutes I thought I was dreaming. The deam came to an end as I figured out how the thing didn't handle relationships

Here was my answer:

If you can afford LLBLGen license, go for it.

I seriously don't like LINQ query-syntax the more I work with it (although I LOVE the language features related to it like Extension Methods and Expression Tres).

I loved at first like everybody else, but being uncertain whether [[ where employee.Name.StartsWith("John Smit") ]] in that XYZ LINQ provider will be done in SQL statement or in LINQ to Objects (after the SQL returns all results), and whether [[ user.Roles.Contains(role) ]] will at all work or not is a big step behind.

LLBLGen can make deleting all items without loading them as easy as

MyEntityCollection.DeleteAll( new MyEntity {Condition = value} );

This is pretty simple and I like it. You get lazy loading and you set eager/deep loading by default and/or per query using Prefetch API. You can compose and construct dynamically (and easily) any filter/sort/loading at infinite levels. It's very nice.

There are only two problems about LLBLGen: first, it's price not all companies would love to pay especially given the hype Microsoft alternatives have. Second, the naming convention although standard in RDBMS theories) like PredicateFactory instead of "where" or "filter" and Prefetch instead of deep loading and even SortExpression instead of orderby, those all are a little scary to a developer working with it for the first times, but soon you learn to love them, given the power and ease they give. There are talks about POCO support in LLBLGen 3.0. I cannot tell about it because I don't know.

Now given I no longer work in a company that uses LLBLGen, the company uses LINQ to SQL mainly because it's "proven" in so many projects without big failures (unlike EF 1, which is lacking even LINQ features in LINQ to SQL and has very bad performance and can be quite limiting in advanced mapping - which it should have been best for!). This website StackOVerflow itself runs on top of it!!! I used both in this company (EF after L2S) and hated both. The decision for new projects remained LINQ to SQL, and doing all we can to overcome it's limitations. You can work around it to do SEMI-POCO (you still need to use some L2S related types when it comes to associations).

I also do some small projects at home. Since I nolonger have LLBLGen license, I decided to learn NHibernate and use it along with Fluent NHibernate and LINQ To NHibernate. I have learned through this that NHibernate is VERY strong. It changed how I work by some features like updating DB schema automatically (I never touched the DB almost when using it). LINQ provider (in NHibernate Contrib project) is quite lacking sometimes but there is the unreleased source code of NHibernate itself contains a better LINQ provider (haven't tried it yet). The "Session" in NHibernate has problems when you are doing web development similar to those related to DataContext in L2S or ObjectContext in EF (LLBLGen doesn't suffer from those thanks to self tracking entities).

The biggest problems I had with NHibernate though was ability to find information. Too many pieces that should be put together in certain way and not much guidance can include advanced information for both mapping and querying. If not I had a friend (Tuna Toksoz , @tehlike on twitter) who happended to be a committer in NHibernate project source code, I'd really be in serious trouble.

The moral I learned was: If you want something that just works and a bit basic use Linq To Sql or SubSonic, if you want something in the middle and your production environment can afford BETA .NET version (given golive exists) use Entity Framework 4.0, if you want something very powerful and can afford the hard learning process go to NHibernate, AND, BEST OF ALL, if you can afford LLBLGen, USE IT.

Let me know your own thoughts on the topic.

Today (technically yesterday, since it’s 3:26 AM already while I’m starting this), Mr. Adam Mohamed Meligy finally arrived home, after staying 9.5 days in nursery. This –dear audience- given Mr. Adam arrived to our world only in October 5, 2009, a date that the entire world will (sooner or later) always remember!

Mr. Adam is now taking a personal cover, pretending to be a normal baby, while he is pretty professional, he cannot sometimes hide his special natures, being relatively quiet compared to normal babies, and highly responsive to touches and (believe it or not) spoken notes/requests.

These are things that the world will remember once Mr. Adam finishes his first big achievement in the field he will take up for living (God Willing). Some other small details matter more to the family, both his grandparents –for example- note him as their first grandchild. I –personally- recognize him as my extra chance in life! If I fail to manage to be another Anders Hejlsberg/Martin Fowler, Scott Guthrie/Brad Abrams, or Scott Hanselman/Rob Conery/Phil Haack (still trying), Mr. Adam has a bigger chance; else wise, he’ll be digging his road as a notable figure in some different field (God Willing).

I feel that I was blessed with not just two more legs and hands, one more tongue and a couple of stronger eyes, extra more years to live, but also with an extra brain and superpowers. You can always upgrade your thinking methodologies, even reinvent the way you think completely, but you are always limited to your physical brain constraints that -although can be always stretched more and more- have their limits. Now I have an extra brain that can do pair thinking with me and reinvent the way things happen by the experiences he will be having on his own (God Willing).

So, this is to log that Mr. Adam (temporarily until he decides to replace that with “Eng.”, “Dr.”, and/or “Prof.”) has just finished implementing phase zero,  coming to existence!

Few More Facts About Mr. Adam’s Arrival

• The exact time of arrival to world is October 5, 2009, 10:30 AM Abu Dhabi Time, that’s 8:30 AM Cairo Local Time (CLT), 6:30 GMT.
• Although born in Kornesh Hospital, Abu Dhabi, UAE, Mr. Adam holds the Egyptian nationality, just like his parents. He also inherits the Islam religion, which he will be (God Willing) discussed about as soon as starts making conversations, so that he practices it for the sake of belief, not inheritance!
• Mr. Adam reached our world after hiding in a secret cafe for slightly less than 35 weeks, reaching our world at the weight of 2.25 Kg.
• Mr. Adam has his email, Facebook and twitter accounts created on the day of arrival and moderated by parents. Soon (God Willing) he will be running those himself, and creating his own LinkedIn account on his own once he finishes his first school and starts a professional expert career simultaneously.
• Mr. Adam has come with the message to make the world a a better place to live for humans, not to dominate the entire world ;-).
• Since arrival, the protocol requires using the prefix “Mr.” when mentioning Mr. Adam’s name in conversations. Only tweets/categories, etc… are allowed exceptions due to technical/official nature. This prefix is temporary as per the relevant note above.

On behalf of the family, I congratulate the world on having Mr. Adam with us. I’ll be following up with his significant news until he starts blogging (hopefully soon, God Willing).

Few minutes ago a colleague and friend asked me about some problem he was having with ASP.NET themes. He was using a theme and including a CSS file in it, the CSS file was linked in the generated HTML but clearly it was not applied. Putting the URL of the CSS file in the browser address bar would return an empty result in Firefox, and a crappy DOCTYPE,HTML,HEAD,BODY tags in IE. The same website works normally with other developers running Windows XP or Windows 7.

Going further to the problem, I tried checking the file access, giving extra permissions and so on, checking web.config and global.asax for any ASP.NET HTTP Handler or HTTP Module that might be handling all requests. None of this existed. Then, I switched to IIS, trying to change the website from custom Application Pool to default integrated pipeline one to default classic (IIS 6 like) one, but no use.

Now I started thinking, images in the website didn’t show also! I didn’t know whether this was a DB/code issue or related to not showing the CSS, well, maybe something is wrong with IIS installation, right? Well, exactly!!!

Here’s what the problem was:

Having installed IIS 7.5 for the first time, the guy thought he just needed to choose ASP.NET features in WWW, he never realized he has to have “Static Content” checked as well. It was really funny when discovered!

Wouldn’t you agree?

Few minutes ago, I saw @mShady, my dear friend (Real life friend, not just on twitter) tweeting:

RT @ASGEgypt: RT @scrum_coach: Should the team be allowed to drop the retrospective? http://bit.ly/bkOgv  #scrum #agile #lean #xp #kanban

I checked the post and found the options are:

1. Yes, It’s their process why not?
2. No, explain to them and work through why the retrospective is so important.
3. Maybe, if they are no longer a team then why continue with Scrum?
4. Only do retrospectives once a quarter and build up a good list of things to change.
5. Yes, the process will take care of itself we don’t need to watch it that closely. After all it’s common sense!

Interesting question! Not the most important topic in Scrum but like the way Agile works in general, if you play with it wrong, it is an indicator you have something else wrong as well before that, so, it gives you an alert.

See the rest of the blog post. I find the options my main interest, and wanted to share with you here how I answered this question:

I’d say have a really short one if the team members have been working together for sometime it can go really quick (an hour or so) just before the planning for the next sprint. We used to do so in a previous company and it was pretty successful.
It was like it’s one meeting divided into 2, one hour or so for previous sprint retrospective, and probably rest of the day (or most of it) for the planning for next sprint.

If they cannot have a quick meeting like this quickly then something else is wrong and they need to work on their team skills. Time boxing would be one option: The meeting will be needed “more” if they do not communicate well, Time box it to 2 hours or so and make it clear and strict since beginning, and consider investigating (assuming you are scrum master or team leader) what other issues the team may be suffering from.

However, I find myself going with (1) and (5) at the same time, “it’s their process” and “After all it’s common sense!”.

What do you think??

Yesterday I changed my twitter username from @Mohamed_Meligy to just @Meligy.

Why?

I have been thinking about this step for a long time, as my tweets are relatively long, and when I want to to allow people to re-tweet. With my old username, I used to have to write at max 120 characters per tweet to allow re-tweet (leaving 20 characters out of the real 140 characters limit to “RT @Mohamed_Meligy: ”). With my new twitter username I can use up to 128 characters (leaving 12 for “RT @Meligy: ”). I know I ‘m a person who can make nice use of those 8 extra characters, but is this worth doing? For sometime I thought: No.

My old username has some nice features. First, it includes my full name, so, that’s nice for people who don’t know me very well. Second, it has been around for over a year and over ~2390 tweets! That’s something!! People got used to using this twitter username when replying to me (mentioning me) and I did my best to put it everywhere in my Google and Facebook profile and blog and everywhere, and also used it with many twitter applications that require entering username/password.

Few days ago, one of my friends brought up the topic and encouraged me to do the change. I tweeted asking my friends whether they would promote the change, and encouraged me even more, so, I switched twitter username to @Meligy.

How

Some friends may wonder, how did I change my twitter username and still kept all my previous followers and reserved the old username also still on twitter. What part of it is a feature of twitter, and what part is something I did?

So, here is the story:

1. I created a new twitter account with username @Meligy, and same password.
2. I changed the @Meligy username to @Mohamed_Meligy2.
3. In another browser I went to my old @Mohamed_Meligy account, changed username to @Meligy. Now I have @Meligy and @Mohamed_Meligy2.
   I noticed When I go to twitter replies in twitter website, it shows all replies that came to me, even those including @Mohamed_Meligy. This is good.
   The bad part is that when I click on @Mohamed_Meligy link in those replies/mentions, it goes to @Mohamed_Meligy not @Meligy.
4. I changed the new account @Mohamed_Meligy2 back to @Mohamed_Meligy.
5. I deleted the old @Mohamed_Meligy account from tweetdeck, and added both @Mohamed_Meligy and @Meligy (as default).
   I couldn’t just add the @Meligy account even with same password in both – I had to delete the old one.
6. I used tweetdeck to tweet from both accounts “Changed twitter username from @Mohamed_Meligy to @Meligy. Followers needn't change anything except using @Meligy in future replies/mentions”.
7. I started trying to remember all the websites and applications I logged with the old twitter username and change it to @Meligy.
   Having the same password on the other @Mohamed_Meligy account, I’ll be monitoring it for a while in case I forget some application or so.

Note that any link to previous tweets (in the format: twitter.com/{username}/status/{tweetID}) before changing username will still be broken.

Follow Me!

If you already followed me back with the old username, you should still be able to receive my updates.

If not, follow me on twitter via @Meligy.

Some of you who use Firefox (FF) might know about a Firefox plug-in called “IE Tab” which allows you to view a page/tab using the Internet Explorer (IE) rendering engine INSIDE Firefox (so, if some page displays better in IE, you don’t have to leave FF and go open an IE window).

Now, Google is doing something similar, but the other way around!

Google has recently released “Google Chrome Frame”, a plug-in for IE that allows you to view a page/tab using the Google Browser “Google Chrome” rendering engine INSIDE Internet Explorer.

This is interesting in two ways, first, it may decrease IE problems with crashes and such, and second, that Google maybe later will drop support for IE rendering engine in its products (like Google Mail, Reader, Video, Youtube, etc..), so that you have to use Firefox, Safari or Google Chrome (or Google chrome Frame) to use these applications.

Interesting enough, this is the case already with one of Google’s new products, called Google Wave!

They say the reason is supporting IE6!! They did much effort to get it to work with it but it didn’t. Of course the Chrome Frame plug-in is supported under IE 6, so, is supposedly solves their problem!

Google Chrome Frame Homepage:

http://www.google.com/chromeframe

Related News:

Google’s Plan to Kill Internet Explorer? Google Wave

Google Has A Solution For Internet Explorer: Turn It Into Chrome

Firefox IE Tab Extension:

http://ietab.mozdev.org/

This was originally an email I sent to .NET team in my company, then decided to share as a blog post.

The problem:

• Let’s say you have a complex application, and this application (or part of it) runs very slowly. No bug s in results, no errors or exceptions, but it just so slow! Now you want to know which part of your code is the reason, which method(s) you need to go and modify., which methods take so long to execute or consume so much memory/CPU. How would you know that?
• Let’s say you want to improve the performance of your application in general (say add caching or such), so, you want to identify which parts of your code deserve your attention and will really make difference (so that you don’t waste your time on optimizing something that will not have big effect in performance), for  example, you might want to identify which methods are called more than others from different parts of your code. How would you do that?

How to solve it, or, what is a profiler (v. short):

It is an application that you can run along with your own program. It’ll track all method calls and how any method call other method and most importantly how long each method call will take, and how it consumes resources.

There are many .NET profilers out there.

• One of them is provided by Microsoft itself. It’s a bit old but works: CLR Profiler
  • Download Page: http://www.microsoft.com/downloads/details.aspx?FamilyID=a362781c-3870-43be-8926-862b40aa0cd0&displaylang=en
  • Learning Resources: http://www.microsoft.com/downloads/details.aspx?familyid=CD5AA57C-9CD1-45AB-AA4B-8DC586D30938&displaylang=en
• Another is DotTrace, this is the best .NET profiler ever! Used by the real gurus out there, like the guys running stackoverflow.com (which is run on asp.net mvc BTW). It’s created by JetBrains, a company that create treasure developer solutions
  • But it’s NOT FREE
  • Check it out anyway! Homepage: http://www.jetbrains.com/profiler/
• Another FREE one is EQATEC. This is very nice simple profiler that I wrote this message for. It focuses on measuring code speed and method call sequence not memory usage
  • Homepage: http://www.eqatec.com/tools/profiler
  • Features: http://www.eqatec.com/tools/profiler/features
  • Complete user guide: http://www.eqatec.com/tools/profiler/guide

So, what about EQATEC:

Quoting from homepage:

Spot slow code

Are you a .NET developer? Would you like your application to run faster? Then use our free profiler to spot you app's slow code.

Point and go

No source code changes are needed. Just point the profiler to your app, run the modified code, and get a visual report.

Speedup any .NET app

As the only code profiler in the world, our profiler can even handle Compact Framework applications.

Language	Version	Platform
C# VB.NET Managed C++ F# C or C++ Java	.NET 3.5 .NET 3.0 .NET 2.0 .NET CF 3.5 .NET CF 2.0 .NET 1.1	WinXP, Vista Windows Mobile Windows CE XP embedded PocketPC, PDA Linux

To use it with ASP.NET application, all you need to is:

• to put the path of the “bin” folder of your website as “App Path” (no need for source code or debug files), then it shows a list of all assemblies in it so you choose the DLL(s) you want to profile, and click “Build” at the right corner of the screen:
  
• Click “Open output folder” on the bottom left corner, copy the DLLs from there to your website “bin” folder
  • Alternatively you can click “App Options” and set the output folder to “$(AppDir)” so that the generated files replace the old one
  • You need to repeat these previous steps if you build the website again using Visual Studio
• run the website and start using it for a while
• go to EQUATEC “Run” tab and click “Take Snapshot
• go to the “View” tab and start reading the results
  • for more information check the user guide: http://www.eqatec.com/tools/profiler/guide

It might be important also to spot the limitations:

Known limitations

This is a list of known limitations and problems in version 2.0.

• Blocking methods, such as Read(), will be counted as the total time, including the time the thread spends being descheduled and waiting for the call to complete. For now, you will have to recognize and judge situations like this manually.
• No debug information is available for the profiled assemblies. It means that you cannot debug the profiled versions - but you would probably not like to do that, anyway.
• No Visual Studio integration yet. We are looking into providing an add-in that will make it even easier to enable profiling your solution's assembly files.
• No full method signature is displayed yet. So if you have several overloaded methods by the same name, or use generic methods, you cannot easily distinguish them as their signature (the method's parameter list) is not displayed anywhere.
• Only defined methods are currently profiled, not referenced ones. So all the methods that your application itself defines will be profiled, but not System.* etc.

I hope this is useful for some of you as it was a real saver at times to me. Thank you very much!

الحلقة 5: محمد مليجي يتكلم عن الـ ORM (Object Relational Mapping)

وصف الحلقة من دوت نت عربي:

محمد مليجي تكلم عن الـ ORM (Object Relational Mapping) و هي برامج مساعدة تستطيع من خلالها نقل المعلومات و تحويلها من طبيعة قاعدة البيانات إلى طبيعة البرامج المبنية بأسلوب الـ Object Oriented. حلقة غنية بالتفاصيل و المعلومات القيمة جدا.

• يمكنكم الاستماع للحلقة و متابعة تقاصيلها كاملة على صفحتها بالموقع
• أو تحميل الحلقة برابط مباشر بصيغة MP3.
• أو الاستماع إليها من خلال هذه الصفحة بالأسفل:

Related Links:

• DotNetArabi Arabic Podcasts Website - Homepage (Arabic)
• DotNetArabi Arabic Podcasts Website – Episodes Archive (Arabic)
• DotNetArabi Episode 5: Mohamed Meligy Talking about ORMs – Homepage (Arabic)
• DotNetArabi Episode 5: Mohamed Meligy Talking about ORMs – Direct Download (Arabic - MP3)
• Emad Ashi – Host of DotNetArabi (Weblog – Twitter: @splashup)
• Mohamed Meligy – Me! (Google Reader – Twitter: @Mohamed_Meligy)

Here’s another email from the internal mailing list of Injazat .NET Ninjas (Ninjazat, AKA  as we call ourselves), that I’m sharing with blog readers as well.

Just a place holder, until I move one of my 18 (just discovered the number now – terrifying!) drafts in my Windows Live Writer into a published post, or delete them all!

Subject: [Learning] Some very interesting videos

Some videos from NDC 2009 event (Norwegian Developers Conference 2009) - about software design and related issues:

· NDC Video – Robert Martin – S.O.L.I.D Principles of OO class design

· NDC Video – Robert Martin – Craftsmanship and Ethics

· NDC Video – Robert Martin – Component Principles

· NDC Video – Robert Martin – Clean Code III – Functions

· NDC Video – Michael Feathers – Working Effectively with Legacy Code

· NDC Video – Jeremy D. Miller – Convention Over Configuration

· NDC Video – Michael Feathers – Seven Blind Alleys in Software Design

· NDC Video – Ted Neward – WCF Patterns

· NDC Video: Michael Feathers – Design Sense

For the complete list of videos from this event check videos from:

· Day 1

· Day 2

· Day 3

My favorite topics are (recommendations):

· NDC Video – Robert Martin – S.O.L.I.D Principles of OO class design

· NDC Video – Michael Feathers – Working Effectively with Legacy Code

Of course the other topics are interesting as well.

Enjoy!