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ROC Basics Postscript

Well that's the end of the tour. By now you probably think we should have called the book Doing Cheap Tricks with ROC.

I thought I'd just add a few general thoughts about where to go from here. Hopefully you've seen that ROC is pretty cool, pretty powerful and very uniform - anything that seems to be a specific technology is really an implementation of a general pattern on the ROC primitives.

Learning ROC is as much about unlearning, keeping in check your default assumptions, learning to relax and let the infrastructure catch you. Here's a few good principles I keep in mind when developing:

Think local. Don't try to think across layers - what I mean is if you concentrate on each space on its own, the relations between spaces take care of themselves. Take the last example - its actually very simple in its parts but trying to imagine it as a whole gets complicated. I didn't write it that way. I thought about the regular mapped web space first and then just wrapped it. ROC allows you to create very powerful engineered systems. Like any good engineering you get there by composition of simple cleanly designed units. Think local and allow the scale invariance of ROC to work for you.

The other piece of advice is: it pays to work from the edges to the middle. More often than not, you find that there is no middle!

Final word. ROC is simple. It only gets complicated when you lose context. So keep it simple. Test the 1-1 relationship between requestor and endpoint. Remember to use the visualizer - it doesn't lie, it captures and shows absolutely every piece of state and allows you to track through and keep tight hold on the context.

Exercises

  1. Go back through the whole book with the visualizer enabled and use it to see how it provides a more complete explanation of the demos than any amount of documentation ever could!

Have fun.

PJR

11/6/2009