mongodb-rx

mongodb-rx

MongoDB RxJava Driver: provides composable asynchronous and event-based observable sequences for MongoDB.

A MongoDB based driver providing support for ReactiveX (Reactive Extensions) by using the RxJava library. All database calls return an Observable allowing for efficient execution, concise code, and functional composition of results.

This module depends on rx module, please read the documentation of rx module before using mongodb-rx.

dependency

<dependency>
 <groupId>org.jooby</groupId>
 <artifactId>jooby-mongodb-rx</artifactId>
 <version>1.5.1</version>
</dependency>

exports

  • MongoClient
  • MongoDatabase (when mongo connection string has a database)
  • MongoCollection (when mongo connection string has a collection)
  • Route.Mapper for mongo observables

usage

import org.jooby.rx.Rx;
import org.jooby.mongodb.MongoRx;

{
  // required
  use(new Rx());

  use(new MongoRx());

  get("/", req -> {
    MongoClient client = require(MongoClient.class);
    // work with client:
  });

}

The mongo-rx module connects to mongodb://localhost. You can change the connection string by setting the db property in your application.conf file:

db = "mongodb://localhost/mydb"

Or at creation time:

{
  // required
  use(new Rx());

  use(new MongoRx("mongodb://localhost/mydb"));
}

If your connection string has a database, then you can require a MongoDatabase object:

{
  // required
  use(new Rx());

  use(new MongoRx("mongodb://localhost/mydb"));

  get("/", req -> {

    MongoDatabase mydb = require(MongoDatabase.class);
    return mydb.listCollections();
  });

}

And if your connection string has a collection:

{
  // required
  use(new Rx());

  use(new MongoRx("mongodb://localhost/mydb.mycol"));

  get("/", req -> {
    MongoCollection mycol = require(MongoCollection.class);
    return mycol.find();
  });

}

query the collection

The module let you return MongoObservable from routes:

{
  // required
  use(new Rx());

  use(new MongoRx());

  get("/pets", req -> {
    MongoDatabase db = require(MongoDatabase.class);
    return db.getCollection("pets")
       .find();
  });

}

Previous example will list all the Pets from a collection. Please note you don’t have to deal with MongoObservable, instead the module converts MongoObservable to Jooby async semantics.

multiple databases

Multiple databases are supported by adding multiple MongoRx instances to your application:

{
  // required
  use(new Rx());

  use(new MongoRx("db1"));

  use(new MongoRx("db2"));

  get("/do-with-db1", req -> {
    MongoDatabase db1 = require("db1", MongoDatabase.class);
    // work with db1
  });

  get("/do-with-db2", req -> {
    MongoDatabase db2 = require("db2", MongoDatabase.class);
    // work with db2
  });

}

The keys db1 and db2 are connection strings in your application.conf:

db1 = "mongodb://localhost/db1"

db2 = "mongodb://localhost/db2"

observable adapter

ObservableAdapter provides a simple way to adapt all Observables returned by the driver. On such use case might be to use a different Scheduler after returning the results from MongoDB therefore freeing up the connection thread.

{
  // required
  use(new Rx());

  use(new MongoRx()
      .observableAdapter(o -> o.observeOn(Schedulers.io())));
}

Any computations on Observables returned by the MongoDatabase or MongoCollection will use the IO scheduler, rather than blocking the MongoDB Connection thread.

Please note the observableAdapter(Function) works if (and only if) your connection string points to a database. It won’t work on mongo://localhost connection string because there is no database in it.

driver options

Driver options are available via connection string.

It is also possible to configure specific options:

db = "mongodb://localhost/pets"

mongo {
  readConcern: default
  writeConcern: ACKNOWLEDGED

  cluster {
    replicaSetName: name
    requiredClusterType: REPLICA_SET
  }

  pool {
    maxSize: 100
    minSize: 10
  }

}

Each option matches a MongoClientSettings method.