Method Detail

• initialize

  public static void initialize()

  Registers an Hooks.onOperatorError(BiFunction) with Reactor that provides a default error handling strategy of forwarding exceptions to the execution error handler.

  This method is idempotent. It only needs to be called once per JVM, regardless of how many Ratpack applications are running within the JVM.

  For a Java application, a convenient place to call this is in the handler factory implementation.

  
   import ratpack.core.error.ServerErrorHandler;
   import ratpack.reactor.ReactorRatpack;
   import ratpack.test.embed.EmbeddedApp;
   import rx.Observable;
   import static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static void main(String... args) throws Exception {
   ReactorRatpack.initialize(); // must be called once for the life of the JVM
   <p>
   EmbeddedApp.fromHandlers(chain -> chain
   .register(s -> s
   .add(ServerErrorHandler.class, (ctx, throwable) ->
   ctx.render("caught by error handler: " + throwable.getMessage())
   )
   )
   .get(ctx -> Observable.<String>error(new Exception("!")).subscribe(ctx::render))
   ).test(httpClient ->
   assertEquals("caught by error handler: !", httpClient.getText())
   );
   }
   }
   

• flux

  public static Flux<Void> flux​(Operation operation)

  Converts a Operation into a Flux.

  The returned flux emits completes upon completion of the operation without emitting a value, and emits the error (i.e. via errer()) if it fails.

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.exec.Operation;
   import ratpack.test.exec.ExecHarness;
   <p>
   import public static org.junit.jupiter.api.Assertions.assertTrue;
   <p>
   public class Example {
   public static boolean executed;
   public static void main(String... args) throws Exception {
   ExecHarness.runSingle(e ->
   Operation.of(() -> executed = true)
   .to(ReactorRatpack::observe)
   .subscribe()
   );
   <p>
   assertTrue(executed);
   }
   }
   

  Parameters:

  operation - the operation

  Returns:

  an observable for the operation

• flux

  public static <T> Flux<T> flux​(Promise<T> promise)

  Converts a Promise into an Flux.

  The returned observable emits the promise's single value if it succeeds, and emits the error (i.e. via onError()) if it fails.

  This method works well as a method reference to the Promise.to(Function) method.

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.exec.Promise;
   import ratpack.test.exec.ExecHarness;
   <p>
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static String value;
   public static void main(String... args) throws Exception {
   ExecHarness.runSingle(e ->
   Promise.value("hello world")
   .to(ReactorRatpack::observe)
   .map(String::toUpperCase)
   .subscribe(s -> value = s)
   );
   <p>
   assertEquals("HELLO WORLD", value);
   }
   }
   

  Type Parameters:

  T - the type of value promised

  Parameters:

  promise - the promise

  Returns:

  an observable for the promised value

• fluxEach

  public static <T,​I extends Iterable<T>> Flux<T> fluxEach​(Promise<I> promise)

  Converts a Promise for an iterable into an Flux.

  The promised iterable will be emitted to the observer one element at a time, like Flux.fromIterable(Iterable).

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.exec.Promise;
   import ratpack.test.exec.ExecHarness;
   <p>
   import java.util.Arrays;
   import java.util.LinkedList;
   import java.util.List;
   <p>
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static void main(String... args) throws Exception {
   final List<String> items = new LinkedList<>();
   ExecHarness.runSingle(e ->
   Promise.value(Arrays.asList("foo", "bar"))
   .to(ReactorRatpack::observeEach)
   .subscribe(items::add)
   );
   <p>
   assertEquals(Arrays.asList("foo", "bar"), items);
   }
   }
   

  Type Parameters:

  T - the element type of the promised iterable

  I - the type of iterable

  Parameters:

  promise - the promise

  Returns:

  an observable for each element of the promised iterable

  See Also:

  flux(ratpack.exec.Promise)

• mono

  public static <T> Mono<T> mono​(Promise<T> promise)

  Converts a Promise into a Mono.

  The returned Single emits the promise's single value if it succeeds, and emits the error (i.e. via onError()) if it fails.

  This method works well as a method reference to the Promise.to(Function) method.

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.exec.Promise;
   import ratpack.test.exec.ExecHarness;
   <p>
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static String value;
   public static void main(String... args) throws Exception {
   ExecHarness.runSingle(e ->
   Promise.value("hello world")
   .to(ReactorRatpack::mono)
   .map(String::toUpperCase)
   .subscribe(s -> value = s)
   );
   <p>
   assertEquals("HELLO WORLD", value);
   }
   }
   

  Type Parameters:

  T - the type of value promised

  Parameters:

  promise - the promise

  Returns:

  a single for the promised value

• promise

  public static <T> Promise<List<T>> promise​(Flux<T> flux)
                                      throws UnmanagedThreadException

  Converts a Flux into a Promise, for all of the observable's items.

  This method can be used to simply adapt an observable to a promise, but can also be used to bind an observable to the current execution.

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.test.exec.ExecHarness;
   import reactor.core.publisher.flux;
   import java.util.List;
   import java.util.Arrays;
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static class AsyncService {
   public <T> Flux<T> flux(final T value) {
   return Flux.create(subscriber ->
   new Thread(() -> {
   subscriber.next(value);
   subscriber.complete();
   }).start()
   );
   }
   }
   <p>
   public static void main(String[] args) throws Throwable {
   List<String> results = ExecHarness.yieldSingle(execution ->
   ReactorRatpack.promise(new AsyncService().flux("foo"))
   ).getValue();
   <p>
   assertEquals(Arrays.asList("foo"), results);
   }
   }
   

  This method uses Flux.collectList() to collect the observable's contents into a list. It therefore should not be used with observables with many or infinite items.

  If it is expected that the observable only emits one element, it is typically more convenient to use promiseSingle(Mono).

  If the observable emits an error, the returned promise will fail with that error.

  This method must be called during an execution.

  Type Parameters:

  T - the type of the value observed

  Parameters:

  flux - the flux

  Returns:

  a promise that returns all values from the observable

  Throws:

  UnmanagedThreadException - if called outside of an execution

  See Also:

  promiseSingle(Mono)

• promiseSingle

  public static <T> Promise<T> promiseSingle​(Mono<T> mono)
                                      throws UnmanagedThreadException

  Converts a Mono into a Promise, for the mono's single item.

  This method can be used to simply adapt an observable to a promise, but can also be used to bind an observable to the current execution.

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.test.exec.ExecHarness;
   import reactor.core.publisher.Mono;
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static class AsyncService {
   public <T> Observable<T> observe(final T value) {
   return Mono.create(subscriber ->
   new Thread(() -> {
   subscriber.success(value);
   subscriber.onCompleted();
   }).start()
   );
   }
   }
   <p>
   public static void main(String[] args) throws Throwable {
   String result = ExecHarness.yieldSingle(execution ->
   ReactorRatpack.promiseSingle(new AsyncService().observe("foo"))
   ).getValue();
   <p>
   assertEquals("foo", result);
   }
   }
   

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.test.exec.ExecHarness;
   import reactor.core.publisher.Flux;
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static void main(String[] args) throws Throwable {
   String result = ExecHarness.yieldSingle(execution ->
   ReactorRatpack.promiseSingle(Mono.<String>just("foo"))
   ).getValue();
   assertEquals("foo", result);
   }
   }
   

  If it is expected that the observable may emit more than one element, use promise(Flux).

  If the observable emits an error, the returned promise will fail with that error. If the observable emits no items, the returned promise will fail with a NoSuchElementException. If the observable emits more than one item, the returned promise will fail with an IllegalStateException.

  This method must be called during an execution.

  Type Parameters:

  T - the type of the value observed

  Parameters:

  mono - the mono

  Returns:

  a promise that returns the sole value from the observable

  Throws:

  UnmanagedThreadException

  See Also:

  promise(Flux)

• publisher

  public static <T> TransformablePublisher<T> publisher​(Flux<T> flux)

  Converts a Flux into a Publisher, for all of the observable's items.

  This method can be used to simply adapt an observable to a ReactiveStreams publisher.

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.exec.stream.Streams;
   import ratpack.test.exec.ExecHarness;
   import reactor.core.publisher.Flux;
   import java.util.List;
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static class AsyncService {
   public <T> Observable<T> flux(final T value) {
   return Flux.create(subscriber ->
   new Thread(() -> {
   subscriber.next(value);
   subscriber.complete();
   }).start()
   );
   }
   }
   <p>
   public static void main(String[] args) throws Throwable {
   List<String> result = ExecHarness.yieldSingle(execution ->
   ReactorRatpack.publisher(new AsyncService().flux("foo")).toList()
   ).getValue();
   assertEquals("foo", result.get(0));
   }
   }
   

  Type Parameters:

  T - the type of the value observed

  Parameters:

  flux - the flux

  Returns:

  a ReactiveStreams publisher containing each value of the flux

• bindExec

  public static <T> Flux<T> bindExec​(Flux<T> source)

  Binds the given flux to the current execution, allowing integration of third-party asynchronous fluxes with Ratpack's execution model.

  This method is useful when you want to consume an asynchronous flux within a Ratpack execution, as a flux. It is just a combination of promise(Flux) and fluxEach(Promise).

  
   import reactor.core.publisher.Flux;
   import ratpack.test.exec.ExecHarness;
   import ratpack.reactor.ReactorRatpack;
   import java.util.Arrays;
   import java.util.List;
   import public static org.junit.Assert.*;
   <p>
   public class Example {
   public static void main(String... args) throws Exception {
   Flux<String> asyncFlux = Flux.create(subscriber ->
   new Thread(() -> {
   subscriber.next("foo");
   subscriber.next("bar");
   subscriber.complete();
   }).start()
   );
   <p>
   List<String> strings = ExecHarness.yieldSingle(e ->
   ReactorRatpack.promise(asyncFlux.compose(ReactorRatpack::bindExec))
   ).getValue();
   <p>
   assertEquals(Arrays.asList("foo", "bar"), strings);
   }
   }
   

  Type Parameters:

  T - the type of item observed

  Parameters:

  source - the observable source

  Returns:

  an observable stream equivalent to the given source

  See Also:

  fluxEach(Promise), promise(Flux)

• fork

  public static <T> Flux<T> fork​(Flux<T> observable)

  Parallelize a flux by forking it's execution onto a different Ratpack compute thread and automatically binding the result back to the original execution.

  This method can be used for simple parallel processing. It's behavior is similar to the subscribeOn but allows the use of Ratpack compute threads. Using fork modifies the execution of the upstream observable.

  This is different than forkEach which modifies where the downstream is executed.

  
   import ratpack.func.Pair;
   import ratpack.reactor.ReactorRatpack;
   import ratpack.test.exec.ExecHarness;
   <p>
   import reactor.core.publisher.Flux;
   <p>
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   import public static org.junit.Assert.assertNotEquals;
   <p>
   public class Example {
   public static void main(String[] args) throws Exception {
   ReactorRatpack.initialize();
   <p>
   try (ExecHarness execHarness = ExecHarness.harness(6)) {
   Integer sum = execHarness.yield(execution -> {
   final String originalComputeThread = Thread.currentThread().getName();
   <p>
   Flux<Integer> unforkedFlux = Flux.just(1);
   <p>
   // `map` is executed upstream from the fork; that puts it on another parallel compute thread
   Flux<Pair<Integer, String>> forkedFlux = Flux.just(2)
   .map((val) -> Pair.of(val, Thread.currentThread().getName()))
   .compose(ReactorRatpack::fork);
   <p>
   return ReactorRatpack.promiseSingle(
   Flux.zip(unforkedFlux, forkedFlux, (Integer intVal, Pair<Integer, String> pair) -> {
   String forkedComputeThread = pair.right;
   assertNotEquals(originalComputeThread, forkedComputeThread);
   return intVal + pair.left;
   })
   );
   }).getValueOrThrow();
   <p>
   assertEquals(sum.intValue(), 3);
   }
   }
   }
   

  Type Parameters:

  T - the element type

  Parameters:

  observable - the observable sequence to execute on a different compute thread

  Returns:

  an observable on the compute thread that fork was called from

  Since:

  1.4

  See Also:

  forkEach(Flux)

• fork

  public static <T> Flux<T> fork​(Flux<T> flux,
                                 Action<? super RegistrySpec> doWithRegistrySpec)
                          throws Exception

  A variant of fork(reactor.core.publisher.Flux<T>) that allows access to the registry of the forked execution inside an Action.

  This allows the insertion of objects via RegistrySpec.add(java.lang.Class<O>, O) that will be available to the forked flux.

  You do not have access to the original execution inside the Action.

  
   import ratpack.exec.Execution;
   import ratpack.exec.registry.RegistrySpec;
   import ratpack.reactor.ReactorRatpack;
   import ratpack.test.exec.ExecHarness;
   <p>
   import reactor.core.publisher.Flux;
   <p>
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static void main(String[] args) throws Exception {
   ReactorRatpack.initialize();
   <p>
   try (ExecHarness execHarness = ExecHarness.harness(6)) {
   String concatenatedResult = execHarness.yield(execution -> {
   <p>
   Observable<String> notYetForked = Observable.just("foo")
   .map((value) -> value + Execution.current().get(String.class));
   <p>
   Observable<String> forkedObservable = ReactorRatpack.fork(
   notYetForked,
   (RegistrySpec registrySpec) -> registrySpec.add("bar")
   );
   <p>
   return ReactorRatpack.promiseSingle(forkedObservable);
   }).getValueOrThrow();
   <p>
   assertEquals(concatenatedResult, "foobar");
   }
   }
   }
   

  Type Parameters:

  T - the element type

  Parameters:

  flux - the flux sequence to execute on a different compute thread

  doWithRegistrySpec - an Action where objects can be inserted into the registry of the forked execution

  Returns:

  an observable on the compute thread that fork was called from

  Throws:

  Exception

  Since:

  1.4

  See Also:

  fork(Flux)

• forkEach

  public static <T> Flux<T> forkEach​(Flux<T> flux)

  Parallelize an observable by creating a new Ratpack execution for each element.

  
   import ratpack.reactor.ReactorRatpack;
   import ratpack.func.Exceptions;
   import ratpack.test.exec.ExecHarness;
   <p>
   import reactor.core.publisher.Flux;
   <p>
   import java.util.List;
   import java.util.Arrays;
   import java.util.LinkedList;
   import java.util.Collection;
   import java.util.Collections;
   import java.util.concurrent.CyclicBarrier;
   <p>
   import public static org.junit.jupiter.api.Assertions.assertEquals;
   <p>
   public class Example {
   public static void main(String[] args) throws Exception {
   ReactorRatpack.initialize();
   <p>
   CyclicBarrier barrier = new CyclicBarrier(5);
   <p>
   try (ExecHarness execHarness = ExecHarness.harness(6)) {
   List<Integer> values = execHarness.yield(execution ->
   ReactorRatpack.promise(
   Flux.just(1, 2, 3, 4, 5)
   .compose(ReactorRatpack::forkEach) // parallelize
   .doOnNext(value -> Exceptions.uncheck(() -> barrier.await())) // wait for all values
   .map(integer -> integer.intValue() * 2)
   .serialize()
   )
   ).getValue();
   <p>
   List<Integer> sortedValues = new LinkedList<>(values);
   Collections.sort(sortedValues);
   assertEquals(Arrays.asList(2, 4, 6, 8, 10), sortedValues);
   }
   }
   }
   

  Type Parameters:

  T - the element type

  Parameters:

  flux - the observable sequence to process each element of in a forked execution

  Returns:

  an observable

• forkEach

  public static <T> Flux<T> forkEach​(Flux<T> flux,
                                     Action<? super RegistrySpec> doWithRegistrySpec)

  A variant of forkEach(reactor.core.publisher.Flux<T>) that allows access to the registry of each forked execution inside an Action.

  This allows the insertion of objects via RegistrySpec.add(java.lang.Class<O>, O) that will be available to every forked flux.

  You do not have access to the original execution inside the Action.

  Type Parameters:

  T - the element type

  Parameters:

  flux - the flux sequence to process each element of in a forked execution

  doWithRegistrySpec - an Action where objects can be inserted into the registry of the forked execution

  Returns:

  an observable

  Since:

  1.4

  See Also:

  forkEach(Flux), fork(Flux, Action)

• computationScheduler

  public static Scheduler computationScheduler​(ExecController execController)

  A scheduler that uses the application event loop and initialises each job as an Execution (via ExecController.fork()).

  Parameters:

  execController - the execution controller to back the scheduler

  Returns:

  a scheduler

• computationScheduler

  public static Scheduler computationScheduler()

  A scheduler that uses the application event loop and initialises each job as an Execution (via ExecController.fork()).

  Returns:

  a scheduler

• ioScheduler

  public static Scheduler ioScheduler​(ExecController execController)

  A scheduler that uses the application io thread pool.

  Parameters:

  execController - the execution controller to back the scheduler

  Returns:

  a scheduler

• ioScheduler

  public static Scheduler ioScheduler()

  A scheduler that uses the application io thread pool.

  Returns:

  a scheduler