MongoDB Diffusion adapter demo

This project contains example code that demonstrates reflection of a MongoDB collection into part of the Diffusion/Reappt topic tree.

MongoDB replication must be enabled, and the adapter should be connected to the primary instance.

Yes, but why?

Reflecting Mongo documents as topics makes it possible to subscribe to changes effecting that document.

TL;DR

Reflect a MongoDB collection into the Diffusion/Reappt topic tree.

Simplest establishment of a suitable MongoDB server

Establish the simplest MongoDB with replication enabled.

% mongo --nodb
> replicaSet = new ReplSetTest({"nodes" : 1, "nodeOptions": {"dbpath": "/tmp/mongodb"} })
> replicaSet.startSet()
> replicaSet.initiate()

This may make that terminal quite noisy, so replace it with another. Log into your Mongo server:

% mongo localhost:20001
> use someMongoDatabase
> for (i=0; i<100; i++) { db.someMongoCollection.insert({count: i}) }

Which will create database someMongoDatabase and collection someMongoCollection holding 100 brief documents.

Usage

Start your Diffusion server, then start the adapter:

java com.pushtechnology.example.mongo.Adapter \
    -du ws://localhost:8080 -dp admin -dc password \
    -mh localhost:20001 -md someMongoDatabase -mc someMongoCollection

Documents from someMongoDatabase.someMongoCollection will appear as topics under MongoDB/someMongoDatabase/someMongoCollection where the OjectID is reused as the topic name.