Decorators

For version 1.0, Lamar's only support for interception is decorators. If you look in the Lamar codebase, you'll find dozens of tests that use a fake type named IWidget:

public interface IWidget
{
    void DoSomething();
}

Let's say that we have service registrations in our system for that IWidget interface, but we want each of them to be decorated by another form of IWidget like this:

public class WidgetDecorator : IWidget
{
    public WidgetDecorator(IThing thing, IWidget inner)
    {
        Inner = inner;
    }

    public IWidget Inner { get; }
    
    public void DoSomething()
    {
        
    }
}

We can configure Lamar to add a decorator around all other IWidget registrations with this syntax:

var container = new Container(_ =>
{
    // This usage adds the WidgetHolder as a decorator
    // on all IWidget registrations
    _.For<IWidget>().DecorateAllWith<WidgetDecorator>();
    
    // The AWidget type will be decorated w/ 
    // WidgetHolder when you resolve it from the container
    _.For<IWidget>().Use<AWidget>();
    
    _.For<IThing>().Use<Thing>();
});

// Just proving that it actually works;)
container.GetInstance<IWidget>()
    .ShouldBeOfType<WidgetDecorator>()
    .Inner.ShouldBeOfType<AWidget>();