I'm seeking ideas for a sample application to demonstrate the capabilities of Rhino Commons. Anyone has suggestions?

It should be geared toward showing the benefits of using this approach, and yet simple enough so it wouldn't take too long to create. And I am kinda sick of bug tracking systems.

Okay, it looks like I can track down fairly easily what books I read, when I read Working Effectively with Legacy Code, I wrote Rhino Mocks. Now I am reading Applying Domain-Driven Design and Patterns, and I wrote the NHibernate Query Generator.

So, what is this all about?

NHibernate has two major API for querying objects. The first one is called the query API, and uses HQL, a language similar to SQL but with OOP aspirations. The second is called the criteria API, and it is far simpler API, but it is also much easier to use.

Here is a simple example of using the criteria API using my Repository sample from yesterday:

Now, those of you that already knows me know that I have a passionate dislike to strings. I wrote a mock objects library because of this issue, so I may need physcological therapy in the future, but I hate strings.

Well, what do I do when there is something that I don't like? I fix it.

In this case, there where two main options, run time proxying and code generation.

Run time proxying is similar to what I do in Rhino Mocks, and it may look like this:

This has the disadvantages of being both ugly and complex, so I turned to the other route. I build a small application which takes an NHibernate mapping file (hbm.xml) file, and output a strongly typed query wrapper. The above query can now be used like this:

This is much better, and of course that you get all the other nice things about the expression API (like Between, In, etc).

You can get it here, binaries only. Source would have to wait for a while, my subversion provider has run out of room. Note that the code it generates relies on a class called NamedExpression. The class is included in the binary, so just add it to your project and you are done.

I also added support for queries, since I didn't want to leave the other side of the API high and dry, it means that you can do this:

Here is a little FAQ

• What does it generate:
  The tool generate strongly typed wrappers for each of the mapped entities and each of their properties. At the moment, is supports querying against properties, many-to-one, and ids.
• How to make it work for all the files in a directory?
  Simply use the batch capabilities of the shell, like this:
  
  for %f in (*.hbm.xml) DO "NHibernate.Query.Generator.exe" %f D:\Queries
  This will run the tool over all the files in the directory, and output them all to the Queries dir.
• How to make it work with ActiveRecord?
  You need to use the isDebug="true" flag in the configuration, and then point the tool to the resulting mapping files.
• Can I get is as a custom tool for Visual Studio?
  It shouldn't be hard to do, but I don't have the time at the moment. Feel free to send me a patch for it when I release the code.

I just realized that I was posting about it all day, but I forgot to mention where you can get it.

You can browse the source repository online here, or get the source using:

You may have noticed that I like to play word games with code, so here is the Inversion of Control interface in Rhino Commons:

The main goal is to be able to say:

The Initialize() method is called at application start, and will set everything up for the rest of the application. This class is to fetch the repositories, so I can generate a complex object graph and handle some interesting scenarios from the start, using generic decorators.

In the end, I didn't go with NHibernate / Transaction integration, for the simple reason that the Repository<T> and With.Transaction{} made them unnececary.

You probably have heard that NDoc's lead developer, Kevin Downs, has announce that the NDoc is Dead. It also came up in the NHibernate devel mailing list, mostly as questions as to the viablity of open source.

I can't tell why other people are working on OSS, some do it for fun, others because it gives them tools or advantages for later on. It is rare that people are getting paid to work on Open Source Software. I know that I started this to sharpen my skills, and right now I am doing this because I like it and because it gives me the chance to do things that I like doing.

I am involved in a number of OSS projects, so I feel that I speak from experiance here. There are no guarantees of the amount of time that an OSS will go if you are not willing to invest time/money in it. If you do, you can either invest your time in fixing bugs, and send the patches to the project, where they are likely to be accepted.

The best way to influence the development of a product is to say what you want, and either help make it happen, or agree to pay for it. Even if your needs will not always fit the mainstream (you want to support NeverHeardOfDB, for instance) release, it can usually be fitted as a native extention to the product.

So, to cut it short, complaining about not getting what you want is not really going to help. You are getting your money's worth.

I forgot to add that I am using a static forwarder class to get a better syntax, so I have this (after the change from RegisterSave()/RegisterDelete() to Save()/Delete() ).

Another thing that I wanted to talk about was the FindAll()/FindOne() methods. While they have their overloads for working with ICriterion (and wait for a surprise there too), they also have overloads for queries.

Now, I believe that one of the responsabilities of good API is to encourage good code, so I don't have any overload which accept a literal query, instead, all the overloads accept the name of a named query, and its parameters.

I'm currently building the API for the my Repository interface (I talked about it here). Here is what I have so far:

Couple of things to note, I don't have Delete or Save methods, instead, I use RegisterSave() and RegisterDelete(), both of those make it clearer that a Unit Of Work is in action here. To make it more explicit (and to allow several repositories to use in a single Unit Of Work, I made the Unit Of Work an explicit concept:

A sample code using this framework will look like this:

Looking at the code, I don't know if RegisterSave() gives anything, to tell you the truth.

I'm using the commit only flush mode with NHibernate, which mean that if you are not commit the transaction, it will not be saved to the database. The problem is that then all my writing to the database will be inside a With.Transaction() block, which mostly make the Register***() mote.

How would you go about testing code that generate code? I can think of only those two approaches:

• Compare strings - very fragile.
• Compiling the generated code and test that - may be complex if what you are generating is basically helper code.

Anything else?

This post is dedicated to HBool, which is always false on Sunday.

I am currently building a "lecture arsenal", which means that I should have a set of lectures that I can give at a moment notice. The idea came from Justin, who usually walks around with a portable projector, so he literally can be in the middle of a talk and start saying: "You know, I have a lecture of that. Give me three minutes and we can start" :-)

What I have at the moment is the following:

• Inversion of Control & Dependency Injection - Introduction
• Inversion of Control & Dependency Injection -
• Using Mocks For Testing – Basic
• Using Mocks For Testing – Advanced
• Introduction to Object Relational Mapping – Nhibernate & Active Record
• Building a web site using Active Record
• Complex scenarios for using OR/M - Taking design patterns into the database layer.
• MonoRail: An MVC web framework for .Net

Anything else that you think that I am qualified to talk about? I thought about:

• Ranting about things that I don't like in ASP.Net

But I don't think that this will be a very good one :-)