I love Lightwire for dependency injection, it’s lightweight, it’s not XML based, and allows for mixins which saves me from having to constantly add constructor properties or setters. However, I was recently confronted with a problem. When using Lightwire for transient beans, I often found myself wanting to inject dependencies, but also pass in some properties/dependencies at runtime (for example, some data somebody entered in a form). Now, an obvious way to do this would be to define the bean without that dependency, create a setter for it, and then add whatever you need to the bean using that. Somehow, it felt like kind of a roundabout way of doing it, so I figured I’d look for a way to be able to do it at the time of bean invocation. In terms of code, here’s what I was looking for:

myBean = application.lightwire.getBean("myBean", form.runTimeData, form.moreData);

INSTEAD OF

myBean = application.lightwire.getBean("myBean");
myBean.setRuntimeData(form.runTimeData);
myBean.setMoreData(form.moreData);

Note that you could also do the above with one setter that would set all the runtime data you want at once. Still, it’s an extra call, and that just bothers me to no end! So after some modifications to the Lightwire code I was almost able to do what I wanted, with a small caveat. I wasn’t able to use numbered arguments, had to settle for named arguments for now (though I’m still working on it). So right now I’m able to do this:

myBean = application.lightwire.getBean(
	objectName="myBean",
	runTimeData=form.runTimeData,
	moreData=form.moreData
);

I’m not 100% happy with it because I’d like to get it working with numbered argument and avoid all that typing, but the arguments/argumentCollection object is a weird one and I haven’t been able to swing that yet. Hoping I’ll come up with some sort of solution eventually (if anybody has some insights in the Java internals of argumentCollection and how to manipulate that, I’m all ears). But for now this works for me.

I’m interested in knowing if anybody else would find this feature useful, or if for any reason this would be bad practice and maybe I’m going about things all wrong. Again, I know it’s kind of a small nitpicky thing, but when you’re coding all day, small details make a big difference!