Event based and Map reduce patterns

Event based

This pattern talks about how the composed of components can post events or listen to events and a medium which is act as the bridge between the listeners and announcers. The medium dispatches the received events to affected listeners and allows listener to register and listen to events of their choice. Nicely written pattern and I used this in CS427 when I developed an android application.

Map reduce

I have introduced to this one when I did functional programming last semester using Ocaml. The idea is applied with parallelism here. The map function is applied in parallel to each object in a set, then the results are collected and combined by the reduce function to get the output. This is implicitly implemented so user’s just needs to supply the map and reduction and everything else will be taken care by the framework. This is very useful pattern as we have larger data sets and like to apply the reductions on it.