A day in the life of...

Sometimes you have a list of objects (say List<PurchaseOrder>) and you want to get all associated objects (say OrderLines) for all the orders in the list. There are 2 ways of doing this in ECO You call a PersistenceService method which takes the list of orders and a string identifying the association name. I don't like this approach because the name of the association may change during modelling and this wont be picked up as an error until runtime. You use the overloaded method which takes an IAssociationEnd. I don't like this either because you have to find the IAssociationEnd instance from the meta-model at runtime, and to do this you'd probably use a name anyway. So, what's the alternative? public static void EnsureRelatedObjects<T>(this IPersistenceService instance, IEnumerable<T> objects, Expression<Func<T, object>> member) where T : IEcoObject {     MemberExpression memberExpression = (MemberExpression)member.Body;     instance.Ensure

I am playing with Prism’s new Aspect Oriented Programming feature. As a learning exercise I am implementing some of the features ECO requires on a class. If all goes well I will end up with aspects I can apply to plain classes and have them run in ECO. One of those features is the ILoopBack2 interface. In order to tackle this interface a small piece at a time I have created my own ILoopBack2 interface, so far with only one method. ILoopBack2 = public interface   function GetValueByIndex(I: Integer): System.Object; end; This method allows the ECO to evaluate OCL (Object Constraint Language) expressions such as "self.FirstName" and have them route via the class’s property, just in case there is any logic in the getter. By implementing an interface which uses an index to identify the property to read it is possible to avoid reflection. So, getting on with it, here is my class definition type   [aspect: EcoAspects.BusinessClass(’DomainClasses.Package1’)]   Person = public cla

This is fun :-) I’ve created an aspect like so type   BusinessClassAttribute = public class(System.Attribute, ITypeInterfaceDecorator)   private     FPackageName: String;     property PackageName: String read FPackageName;   protected   public     constructor (PackageName: String);     method HandleInterface(Services: RemObjects.Oxygene.Cirrus.IServices; aType: RemObjects.Oxygene.Cirrus.ITypeDefinition);   end; I can now decorator my class like so type   [aspect: BusinessClass(’DomainClasses.Package1’)]   Person = class   end; I can ensure this class  exists in the aspect implementation method. constructor BusinessClassAttribute(PackageName: String); begin   FPackageName := PackageName; end; method BusinessClassAttribute.HandleInterface(Services: RemObjects.Oxygene.Cirrus.IServices; aType: RemObjects.Oxygene.Cirrus.ITypeDefinition); var   PackageType: ITypeReference; begin   PackageType := Services.FindType(PackageName);   if (PackageType = nil) then     Services.EmitError(’Package cl

Here’s what I did. 01: I created a support project which just has a logger class in it. namespace EcoSupport.pas; interface uses   System.Collections.Generic,   System.Linq,   System.Text; type   Logger = public class   private   protected   public     class procedure Log(Message : String);   end; implementation class procedure Logger.Log(Message : String); begin   System.Diagnostics.Debug.WriteLine(’Log: ’ + Message); end; end. 02: I created an Aspect which decorates methods, giving me the opportunity to intercept all method calls on the class it decorates. namespace EcoAspects; interface uses   System.Collections.Generic,   System.Linq,   System.Text,   RemObjects.Oxygene.Cirrus,   EcoSupport; type   [AttributeUsage(AttributeTargets.Class)]   LogAspect = public class(System.Attribute, RemObjects.Oxygene.Cirrus.IMethodImplementationDecorator)   private   protected   public     method HandleImplementation(Services: IServices; aMethod: IMethodDefinition);   end; implementation method

http://blogs.remobjects.com/blogs/ck/2009/02/06/p251 Read the comments I posted to see why I like it!

My employer's support contract has finally come to an end which means I have to look for another job, haven't had to do that in a while! Drop me an email if you have any positions vacant, in the meantime it's time to do a little "networking".

The outcome of this fairly long exchange on codeplex has made me very happy!