Consider a system that has many processes installed in various configurations on many machines.

It’s quite a bit more difficult to do automated integration tests in this environment.

Udi,

I’m not sure I understand the problem with their solutions. You shouldn’t need to intercept anything. The lambda function will simply be an Action which you can store either alongside (or using whatever Spring’s equivalent is to a Windsor’s “Facility”). Then, when you create an instance, invoke all those Action objects on the newly built object.

Is there a specific problem with the need to use the container to set the properties rather than invoke them manually after the container builds the instance? If there is, I’m not sure you could get away with using Expressions without some funky hack, since you would probably want to use the setter, but IIRC Expressions do not allow for using the assignment operator.

Re, “All you need to do is strip out the property name and value both from the expression passed in.”

How do I do that?

Just like in my reply to Jeremy Gray, I still need to generate an instance of the class which allows me to intercept calls to its properties for that to work.

The difficulty is in knowing what the expression (or function) does so that I can use it to configure the underlying component, so I’m afraid that what you showed would run into the same problems.

I think you’re exaggerating the problem though. Any level of automated testing should find those errors in an easy to troubleshoot manner. StructureMap would blow up if any argument was missing and tell you the exact constructor argument that was missing. If your IoC configuration is in any way complex, put some environment tests into your build procedures that check on all the configured instances.

If you really need to get at that configuration information as _data_, you could do the same thing in .NET 3.5 by accepting an Expression rather than an Action as the parameter to OnActivating() – with some minor restrictions.

Cheers

How about considering configuration based on a function? E.g. along the lines of:

builder
.ConfigureComponent(ComponentCallModelEnum.Singleton)
.OnActivating(instance => {
instance.DefaultNumberOfSendThreads = 10;
instance.DefaultNumberOfWorkerThreads = 20;
});

?

Cheers,

Nick

(I don’t know how well the characters will make it through your comment system, but hopefully the point will come across.)

builder.ConfigureComponent(ComponentCallModelEnum.Singleton)
.Configure(o => o.DefaultNumberOfSenderThreads = 10)
.Configure(o => o.DefaultNumberOfWorkerThreads = 10);

or some version that merges both property assignments into one lambda passed into a single .Configure call? These delegates would then be executed directly against the instantiated component, and could even be typed as Expression instead of Func if you wanted to be able to generate their text representation at runtime to provide diagnostic output.