/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.jooby.rx;
import static java.util.Objects.requireNonNull;
import static javaslang.API.$;
import static javaslang.API.Case;
import static javaslang.API.Match;
import static javaslang.Predicates.instanceOf;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Executor;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Function;
import org.jooby.Deferred;
import org.jooby.Env;
import org.jooby.Route;
import org.jooby.exec.Exec;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.google.inject.Binder;
import com.typesafe.config.Config;
import com.typesafe.config.ConfigFactory;
import rx.Completable;
import rx.Observable;
import rx.Scheduler;
import rx.Single;
import rx.Subscriber;
import rx.plugins.RxJavaPlugins;
import rx.plugins.RxJavaSchedulersHook;
import rx.schedulers.Schedulers;
/**
* <h1>rxjava</h1>
* <p>
* Reactive programming via <a href="https://github.com/ReactiveX/RxJava">RxJava library</a>.
* </p>
* <p>
* RxJava is a Java VM implementation of <a href="http://reactivex.io">Reactive Extensions</a>: a
* library for composing asynchronous and event-based programs by using observable sequences.
* </p>
*
* <h2>exports</h2>
* <ul>
* <li>Route mapper that converts {@link Observable} (and family) into {@link Deferred} API.
* </li>
* <li>
* manage the lifecycle of {@link Scheduler schedulers} and make sure they go down on application
* shutdown time.
* </li>
* </ul>
*
* <h2>usage</h2>
* <pre>{@code
* ...
* import org.jooby.rx.Rx;
* ...
*
* {
* use(new Rx());
*
* get("/", req -> Observable.from("reactive programming in jooby!"));
* }
* }</pre>
*
* <h2>how it works?</h2>
* <p>
* Previous example is translated to:
* </p>
* <pre>{@code
* {
* use(new Rx());
*
* get("/", req -> {
*
* return new Deferred(deferred -> {
* Observable.from("reactive programming in jooby!")
* .subscribe(deferred::resolve, deferred::reject);
* });
*
* });
* }
* }</pre>
*
* <p>
* Translation is done via {@link Rx#rx()} route mapper. If you are a
* <a href="https://github.com/ReactiveX/RxJava">rxjava</a> programmer then you don't need to worry
* for learning a new API and semantic. The {@link Rx#rx()} route mapper deal and take cares of
* the {@link Deferred} API.
* </p>
*
* <h2>rx mapper</h2>
* <p>
* Advanced observable configuration is allowed via function adapter:
* </p>
*
* <pre>{@code
* ...
* import org.jooby.rx.Rx;
* ...
*
* {
* use(new Rx()
* .withObservable(observable -> observable.observeOn(Scheduler.io()),
* .withSingle(single -> single.observeOn(Scheduler.io()),
* .withCompletable(completable -> completable.observeOn(Scheduler.io()));
*
* get("/observable", req -> Observable...);
*
* get("/single", req -> Single...);
*
* ....
*
* get("/completable", req -> Completable...);
*
* }
* }</pre>
*
* <p>
* Here every Observable/Single/Completable from a route handler will observe on the <code>io</code>
* scheduler.
* </p>
*
* <h2>schedulers</h2>
* <p>
* This module provides the default {@link Scheduler} from
* <a href="https://github.com/ReactiveX/RxJava">rxjava</a>. But also let you define your own
* {@link Scheduler scheduler} using the {@link Exec} module.
* </p>
*
* <pre>
* rx.schedulers.io = forkjoin
* rx.schedulers.computation = fixed
* rx.schedulers.newThread = "fixed = 10"
* </pre>
*
* <p>
* The previous example defines a:
* </p>
* <ul>
* <li>forkjoin pool for {@link Schedulers#io()}</li>
* <li>fixed thread pool equals to the number of available processors for
* {@link Schedulers#computation()}</li>
* <li>fixed thread pool with a max of 10 for {@link Schedulers#newThread()}</li>
* </ul>
*
* <p>
* Of course, you can define/override all, some or none of them. In any case the {@link Scheduler}
* will be shutdown at application shutdown time.
* </p>
*
* @author edgar
* @since 1.0.0.CR3
*/
@SuppressWarnings("rawtypes")
public class Rx extends Exec {
static class DeferredSubscriber extends Subscriber<Object> {
private Deferred deferred;
private AtomicBoolean done = new AtomicBoolean(false);
public DeferredSubscriber(final Deferred deferred) {
this.deferred = deferred;
}
@Override
public void onCompleted() {
if (done.compareAndSet(false, true)) {
deferred.resolve((Object) null);
}
deferred = null;
}
@Override
public void onError(final Throwable cause) {
done.set(true);
deferred.reject(cause);
}
@Override
public void onNext(final Object value) {
if (done.compareAndSet(false, true)) {
deferred.resolve(value);
}
}
}
/** The logging system. */
private final Logger log = LoggerFactory.getLogger(getClass());
private Function<Observable, Observable> observable = Function.identity();
private Function<Single, Single> single = Function.identity();
private Function<Completable, Completable> completable = Function.identity();
/**
* Creates a new {@link Rx} module.
*/
public Rx() {
// daemon by default.
daemon(true);
}
/**
* Map a rx object like {@link Observable}, {@link Single} or {@link Completable} into a
* {@link Deferred} object.
*
* <pre>{@code
* ...
* import org.jooby.rx.Rx;
* ...
*
* {
* with(() -> {
* get("/1", req -> Observable...);
*
* get("/2", req -> Single...);
*
* ....
*
* get("/N", req -> Completable...);
*
* }).map(Rx.rx());
* }
* }</pre>
*
* @return A new mapper.
*/
public static Route.Mapper<Object> rx() {
return rx(Function.identity(), Function.identity());
}
/**
* Map a rx object like {@link Observable}, {@link Single} or {@link Completable} into a
* {@link Deferred} object.
*
* <pre>{@code
* ...
* import org.jooby.rx.Rx;
* ...
*
* {
* use(new Rx());
*
* with(() -> {
* get("/1", req -> Observable...);
*
* get("/2", req -> Observable...);
*
* ....
*
* get("/N", req -> Observable...);
*
* }).map(Rx.rx(
* observable -> observable.observeOn(Scheduler.io()),
* single -> single.observeOn(Scheduler.io()),
* completable -> completable.observeOn(Scheduler.io())));
* }
* }</pre>
*
* @param observable Observable adapter.
* @param single Single adapter.
* @return A new mapper.
*/
public static Route.Mapper<Object> rx(final Function<Observable, Observable> observable,
final Function<Single, Single> single) {
return rx(observable, single, Function.identity());
}
/**
* Map a rx object like {@link Observable}, {@link Single} or {@link Completable} into a
* {@link Deferred} object.
*
* <pre>{@code
* ...
* import org.jooby.rx.Rx;
* ...
*
* {
* use(new Rx());
*
* with(() -> {
* get("/1", req -> Observable...);
*
* get("/2", req -> Observable...);
*
* ....
*
* get("/N", req -> Observable...);
*
* }).map(Rx.rx(
* observable -> observable.observeOn(Scheduler.io()),
* single -> single.observeOn(Scheduler.io()),
* completable -> completable.observeOn(Scheduler.io())));
* }
* }</pre>
*
* @param observable Observable adapter.
* @param single Single adapter.
* @param completable Completable adapter.
* @return A new mapper.
*/
@SuppressWarnings("unchecked")
public static Route.Mapper<Object> rx(final Function<Observable, Observable> observable,
final Function<Single, Single> single, final Function<Completable, Completable> completable) {
requireNonNull(observable, "Observable's adapter is required.");
requireNonNull(single, "Single's adapter is required.");
requireNonNull(completable, "Completable's adapter is required.");
return Route.Mapper.create("rx", v -> Match(v).of(
/** Observable : */
Case(instanceOf(Observable.class),
it -> new Deferred(deferred -> observable.apply(it)
.subscribe(new DeferredSubscriber(deferred)))),
/** Single : */
Case(instanceOf(Single.class),
it -> new Deferred(deferred -> single.apply(it)
.subscribe(new DeferredSubscriber(deferred)))),
/** Completable : */
Case(instanceOf(Completable.class),
it -> new Deferred(deferred -> completable.apply(it)
.subscribe(new DeferredSubscriber(deferred)))),
/** Ignore */
Case($(), v)));
}
/**
* Apply the given function adapter to observables returned by routes:
*
* <pre>{@code
* {
* use(new Rx().withObservable(observable -> observable.observeOn(Schedulers.io())));
*
* get("observable", -> {
* return Observable...
* });
* }
* }</pre>
*
* @param adapter Observable adapter.
* @return This module.
*/
public Rx withObservable(final Function<Observable, Observable> adapter) {
this.observable = requireNonNull(adapter, "Observable's adapter is required.");
return this;
}
/**
* Apply the given function adapter to single returned by routes:
*
* <pre>{@code
* {
* use(new Rx().withSingle(observable -> observable.observeOn(Schedulers.io())));
*
* get("single", -> {
* return Single...
* });
* }
* }</pre>
*
* @param adapter Single adapter.
* @return This module.
*/
public Rx withSingle(final Function<Single, Single> adapter) {
this.single = requireNonNull(adapter, "Single's adapter is required.");
return this;
}
/**
* Apply the given function adapter to completable returned by routes:
*
* <pre>{@code
* {
* use(new Rx().withObservable(observable -> observable.observeOn(Schedulers.io())));
*
* get("completable", -> {
* return Completable...
* });
* }
* }</pre>
*
* @param adapter Completable adapter.
* @return This module.
*/
public Rx withCompletable(final Function<Completable, Completable> adapter) {
this.completable = requireNonNull(adapter, "Completable's adapter is required.");
return this;
}
@Override
public void configure(final Env env, final Config conf, final Binder binder) {
// dump rx.* as system properties
conf.getConfig("rx")
.withoutPath("schedulers").entrySet()
.forEach(
e -> System.setProperty("rx." + e.getKey(), e.getValue().unwrapped().toString()));
Map<String, Executor> executors = new HashMap<>();
super.configure(env, conf, binder, executors::put);
env.router()
.map(rx(observable, single, completable));
/**
* Side effects of global/evil static state. Hack to turn off some of this errors.
*/
trySchedulerHook(executors);
// shutdown schedulers: silent shutdown in dev mode between app reloads
env.onStop(() -> {
try {
Schedulers.shutdown();
} catch (Throwable ex) {
log.debug("Schedulers.shutdown() resulted in error", ex);
}
});
}
@Override
public Config config() {
return ConfigFactory.parseResources(getClass(), "rx.conf");
}
private void trySchedulerHook(final Map<String, Executor> executors) {
RxJavaPlugins plugins = RxJavaPlugins.getInstance();
try {
plugins.registerSchedulersHook(new ExecSchedulerHook(executors));
} catch (IllegalStateException ex) {
// there is a scheduler hook already, check if ours and ignore the exception
RxJavaSchedulersHook hook = plugins.getSchedulersHook();
if (!(hook instanceof ExecSchedulerHook)) {
throw ex;
}
}
}
}