Clojure Adaptor for RxJava

This adaptor provides functions and macros to ease Clojure/RxJava interop. In particular, there are functions and macros for turning Clojure functions and code into RxJava Func* and Action* interfaces without the tedium of manually reifying the interfaces.

Basic Usage

Requiring the interop namespace

The first thing to do is to require the namespace:

(ns my.namespace
  (:require [rx.lang.clojure.interop :as rx])
  (:import [rx Observable]))

or, at the REPL:

(require '[rx.lang.clojure.interop :as rx])

Using rx/fn

Once the namespace is required, you can use the rx/fn macro anywhere RxJava wants a rx.util.functions.Func object. The syntax is exactly the same as clojure.core/fn:

(-> my-observable
    (.map (rx/fn [v] (* 2 v))))

If you already have a plain old Clojure function you'd like to use, you can pass it to the rx/fn* function to get a new object that implements rx.util.functions.Func:

(-> my-numbers
    (.reduce (rx/fn* +)))

Using rx/action

The rx/action macro is identical to rx/fn except that the object returned implements rx.util.functions.Action interfaces. It's used in subscribe and other side-effect-y contexts:

(-> my-observable
    (.map (rx/fn* transform-data))
    (.finallyDo (rx/action [] (println "Finished transform")))
    (.subscribe (rx/action [v] (println "Got value" v))
                (rx/action [e] (println "Get error" e))
                (rx/action [] (println "Sequence complete"))))

Gotchas

Here are a few things to keep in mind when using this interop:

• Keep in mind the (mostly empty) distinction between Func and Action and which is used in which contexts
• If there are multiple Java methods overloaded by Func arity, you'll need to use a type hint to let the compiler know which one to choose.
• Methods that take a predicate (like filter) expect the predicate to return a boolean value. A function that returns a non-boolean value will result in a ClassCastException.

Binaries

Binaries and dependency information for Maven, Ivy, Gradle and others can be found at http://search.maven.org.

Example for Maven:

<dependency>
    <groupId>com.netflix.rxjava</groupId>
    <artifactId>rxjava-clojure</artifactId>
    <version>x.y.z</version>
</dependency>

and for Ivy:

<dependency org="com.netflix.rxjava" name="rxjava-clojure" rev="x.y.z" />

and for Leiningen:

[com.netflix.rxjava/rxjava-clojure "x.y.z"]