Monthly Archives: March 2006

Jeffrey Palermo 2:44 pm on March 30, 2006
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Consider voting for my Birds of a Feather session at Tech Ed – level 100

I have submitted two BoF sessions for consideration.  These two subjects are ones I deal with ona  day-to-day basis.  If you are going to Tech Ed and are interested in these topics, go to https://www.msteched.com/cfp/bofvoting.aspx and vote.

Voting closes on Friday!

Executable requirements with FIT and FitNesse

What
if your requirements documents could be fed into a tool and executed to
validate the software? That’s exactly what FIT is. The customer can
define requirements and run them. Not only can software be validated at
any time, but requirements are guaranteed to remain current
documentation of the system. Come discuss this emerging concept and
tools to support it.
Intended Audience: IT Pro; Developer
Submitted By: Jeffrey Palermo, DataCert, Inc

Agile Development with .Net

Agile
development is gaining wide adoption and for good reason. Come discuss
the range of practices available to speed development with .Net. We’ll
discuss the many practices in the Agile umbrella that can be used by
themselves and combined together. This discussion will also talk about
tools available to help with development.
Intended Audience: Developer
Submitted By: Jeffrey Palermo, DataCert, Inc

Jeffrey Palermo 3:32 am on March 29, 2006
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Juice is an open source podcast downloader – level 100

Blake Caraway made me aware of this cool program.  Juice is a
podcast downloader and manager.  Install this small program and
subscribe to your podcast feeds.  Juice will automatically take
care of updating these feeds and sucking down the new podcasts. 
Once set up, all you have to do is copy the files to your MP3 player
every once in a while. 

Until I found this, I’d been manually saving off each podcast
file.  This program fills a very specific niche, and I thank the
authors!

Jeffrey Palermo 2:30 am on March 29, 2006
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Rocky gets it all wrong about Test-Driven Development (TDD) – level 200

I’m listening to the latest .Net Rocks show with Rocky Lhotka, and I’m saddened that he gets it so wrong about TDD.  DNR’s last episode ROCKED with Jean Paul Boodhoo,
who talked about TDD and other Agile concepts.  Jean Paul is a
practitioner of TDD, as am I, and he explained the process and its
benefits very well.  Congrats, Jean Paul on a job well done.

Rocky, on the other hand, gets it all wrong.  I respect Rocky and
his contributions to the developer community, but he’s wrong on this
issue.  Let me recap:

At the beginning of the dnr show, he comments on TDD.  He makes
some invalid points.  His points are bulleted, and my responses
are in green:

  • It comes from the premise that you don’t have intellisense in the IDE.
    • I’m really not sure how he came up with this since most other good IDEs have intellisense. 
  • In the Microsoft space, you lose so much by going down the road to TDD.
    • This is a very vague statement, but I’ve
      gained so much by doing TDD.  My rate of development has sped up
      because my debugging time has gone almost down to zero!
  • Rocky misunderstands the process because he states that it involves writing a bunch of tests first before coding.
    • TDD involves writing a single test first and writing code to fulfill it.
  • He states that on large systems, you can’t do it one test method at a time.
    • Can’t?  Any large system is made up
      of smaller parts, down to actual classes and methods as the building
      blocks.  TDD helps define the classes and methods.  TDD
      forces you to start small, but helps build a solid foundation.
  • He says that developers don’t think the way of “test-first”.
    • This is actually a true statement but in
      no way is a weakness of TDD.  Test-first is a learned method just
      like programming as a whole.  Learning to think first is very
      similar to understanding the purpose of the code first.  If you
      can understand the purpose of the code before writing the code, you end
      up with less code churn and a clean class design.
  • Rocky relates that he has always made small test projects or console apps to be test harnesses to test code.
    • I used to do that also, until I graduated to NUnit.
    • These test harnesses are valuable, but as
      you accumulate them, they are hard to manage, and since they are
      valuable, you don’t want to throw them away.  NUnit allows these
      test harnesses to be managed effectively.  Each test method is a
      test harness.

Another false point made in conversation is that once these test
fixtures are created, developers will be hesitant to refactor code
because it would cause them to have to refactor all the tests that use
the code.  Let me say from experience that unit test coverage
makes me want to refactore MORE!  I am so comfortable refactoring
because I have unit test coverage that assures me that I haven’t broken
anything.  In fact, when I am in parts of the code that is older
and doesn’t have good test coverage, I am scared of refactoring because
I have no way of being sure that I didn’t break anything.  Note,
that I also use Resharper, and I would not want to code at all without
it or the DevExpress tools.

I love .Net Rocks, and I’ve listened to it from the very first show (and I’ve been a guest),
and I’m glad all viewpoints are represented, but the above bullet
points are incorrect, and I hope some of you will comment on them as well.

Jeffrey Palermo 1:10 pm on March 24, 2006
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Keep Virtual PC from hogging your computer while installing Windows Vista ctp – level 200

I’m installing the CTP of Vista on a Virtual PC to check it out, but the install is going to take a while, and I don’t want VirtualPC to hog my CPU while I work (no dual core proc for me yet).  I have plenty of RAM, so that’s not an issue, so my CPU is the bottleneck in computer speed.  I found a simple solution that allows me to continue to work while a Virtual PC is cranking away.

Set the thread priority of Virtual PC to “low”.  Windows will now allow anything else to run more often than Virtual PC (cpu timeslicing).  If you’ve never adjusted thread priorities before, you can do this with Task Manager.  Notice that my Commit charge is high, but I have 2GB of RAM, so I’m not worried.  At the top, notice that I have a NAnt build running.  I want NAnt to go fast, so it’s normal priority.  The only process I’ve changed is Virtual PC.

Note:  I almost never change thread priorities, and I don’t recommend doing so, but in this case, it serves a specific purpose.

Windows Vista is slowly installing in the background while I’m able to continue to work without being affected.  Virtual PC is effectively only using idle CPU time.

Jeffrey Palermo 2:37 pm on March 21, 2006
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Web service versioning for dummies – level 200

This post is aimed at providing a good way to version web services.  Note that there are many ways to do this, and this is just one way.

When versioning a service, it’s important to be able to run multiple versions side by side.  When you upgrade the web service for one client, you can’t immediately take away the current version from existing clients.  Existing clients will move to the new version if/when they can/want to.

The identifier for the web service is the Url, so the version number must be embedded in the url.

Here is one way to do it:
https://theServer/v1_0/theService.asmx
When you want to modify the web service, do so, but deploy it side-by-side with the current version:
https://theServer/v1_5/theService.asmx

With this versioning strategy, you will be able to publish upgraded web services while maintaining service to existing customers.  Down the road, when you have confirmed that all customers of the v1.0 service have moved to the v1.5 service, you can discontinue the v1.0 version.

I’ve learned that if there are urls with dots (.) in the path, then the IIS lockdown tool won’t work with them.  For that reason, it’s probably good to use (_) instead of (.) for the version delimiter.  I also agree with the first commenter that major and minor versions are enough.

There are plenty of folks talking about web service versioning:
http://www-128.ibm.com/developerworks/webservices/library/ws-version/
http://www.webservicesarchitect.com/content/articles/irani04.asp

Jeffrey Palermo 2:22 pm on March 14, 2006
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Integrate FitNesse tests with CruiseControl.Net – level 400

On my team, we have FitNesse tests surrounding our system.  We’ve integrated them into our cruise build as well.  We developed custom Xsl sheets so that the cruise build report includes fitnesse information.  We even have our regression FitNesse suite fail the build if any FIT tests fail.  When this happens, the cruise build report shows us the actual FitNesse test that failed with the actual fixture tables.  It’s a great way to report this status.  If you are interested in this technique, my colleague, Steve Donie has posted the Xsl stylesheet on his blog.

Jeffrey Palermo 2:00 pm on March 14, 2006
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Using enum strings with NHibernate persistence – level 400

One of the things that is not very obvious when using NHibernate is how to using Enumerations.  If you merely map an enum with the hbm.xml, NHibernate will persist that class member as an int, which is the underlying type of an Enum value type.  Even if you have your database table configured with a string field, you’ll get an integer in your string field.

To have NHibernate use the string representation of the enum for storing in the database, you need to use a special type class.  Below is a simple example of using the EnumStringType that NHibernate provides.  Consider the following enum that I want to use in my class (this is a very simplified example):

    public enum DeliveryStatus
    {
        Pending,
        Ready,
        Sent
    }

When mapping this in my class, NHibernate would persist 0, 1, and 2 in my database.  What I actually want are the strings to be stored in my table (no comments about normalization, please).  Here is a wierd thing you have to do to achieve this goal.  Here is my mapping:
<?xml version=”1.0″ encoding=”utf-8″ ?>
<hibernate-mapping xmlns=”urn:nhibernate-mapping-2.0″>
    <class name=”Palermo.Shipping.Shipment, Palermo.Shipping” table=”Shipment”>
        <id name=”TrackingId” column=”TrackingId” type=”String” length=”30″ >
            <generator class=”assigned”/>
        </id>
       
        <property name=”DeliveryState” column=”DeliveryState”
            type=”Palermo.Shipping.DeliveryStatusType, Palermo.Shipping”/>
       
    </class>

</hibernate-mapping>

Notice that I have a new type referenced for DeliveryState:  DeliveryStatusType.  This is what’s new.  This type helps NHibernate map an enum string instead of the int.  For this, I must define this type in my code:

    public class DeliveryStatusType : EnumStringType
    {
        public DeliveryStatusType() : base(typeof (DeliveryStatus), 30)
        {
        }
    }

Note that this is very simple, and the 30 specifies the max length of the enum string.  I’d recommend setting this number the same as the length of your string field in your database.

With these small steps, NHibernate will now map Pending, Ready, and Sent to the database field.  Normal programmatic interaction is the same.  NHibernate will take care of all the data access.  Without the above solution, one might be tempted to use string constants, but I’d highly recommend using enums when the possible values are known. 

Gabriel Lozano-Moran agrees, and he posts some good principles surrounding it.
Jeffrey Palermo 12:46 pm on March 13, 2006
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INETA speaker Miguel Castro at ADNUG tonight – level 000

Miguel Castro will be talking about custom web controls tonight at the Austin .Net User Group.  If you’ve heard his .Net Rocks show or watched his DNR TV episode1 and episode2, you know that it’ll be a great talk for those wanted to create their own custom controls.

Miguel came into town (Austin, TX) Saturday night, and I spent Sunday showing him around the area.  It’s beautiful hill country, and he was amazed that while driving past houses, complete strangers would smile and wave.  The greater Austin area is so much more than just the city of Austin.  I would say that the city is the smallest part.  The surrounding area is really the draw.  I live two towns away in Leander, TX, and it still only takes me 30 minutes to get in to Austin to work. 

One of the things that amazed Miguel most is that here in Texas, our Wal-marts have gun departments. 🙂

Jeffrey Palermo 8:35 am on March 11, 2006
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EVERY application has a natural domain model – level 200

I’m in the camp that loves OO.  I want smart objects for
everything.  I don’t like data-centric programming.  I don’t
like thowing raw data around in DataSets.  I create custom objects
for everything in my applications.  I was reflecting on a very
simple application, and I realized that every application has a natural
domain model.  I’ve had conversations where a developer has said,
“Our application is different.  It’s not an enterprise
application.  Domain-driven design doesn’t apply.”  I’ve come
up with a really simple example to illustrate my point.

Suppose you have an application that only maintains social security
numbers.  That’s it. It doesn’t store person information, just
social security numbers.  In fact, your entire database is one
table with one char(9) field.  One might just go ahead and
keep the social security numbers in a string.  Would that
work?  Yes, but consider the natural domain object for this:

    public class SocialSecurityNumber
    {
        private string _rawNumber;

        public SocialSecurityNumber(string number)
        {
            _rawNumber = number;
        }

        public string GetWithoutDashes()
        {
            return; //the ssn without dashes.
        }

        public override string ToString()
        {
            //format ssn nicely and output.
            return; //the nice output.
        }

        public override bool Equals(object obj)
        {
            return true; //or false if they don’t match.
            //Use some intelligence to compare for sameness.
        }
    }

You could store the information in a string, but then that is a magic
string floating around your application, and every class _just_ has to
know that it must be a social security number.  There is no strong
typing to enforce that there are exactly 9 numerals in the
string.  What about dashes?  with this SocialSecurityNumber
class, you have your domain model, and now you can enforce all the
rules about the number easily.  Maybe you want to always store it
in the database without dashes but want to display it on the UI with
dashes.  Instead of string manipulation elsewhere, encapsulate
that logic directly inside the domain object.  If you use this
object throughout your system, it’s clear that constraints will always
be enforced, and you never have double check that a social security
number is really there – the compiler picks up that burden for you as
well as runtime strong type checking.

Consider your current applications.  Do you have a prominent
string, bool, or int?  Would it be helpful if that piece of
information could carry around describing and validating
information?  Consider creating a domain object to house that
single piece of information and enforce rules about it.  I think
it’ll make the application a lot simpler.