io.helidon.docs.mp.reactivemessaging.IntroductionSnippets Maven / Gradle / Ivy
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* Copyright (c) 2024 Oracle and/or its affiliates.
*
* Licensed 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 io.helidon.docs.mp.reactivemessaging;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionStage;
import io.helidon.common.reactive.Multi;
import jakarta.enterprise.context.ApplicationScoped;
import jakarta.inject.Inject;
import jakarta.ws.rs.Consumes;
import jakarta.ws.rs.PUT;
import jakarta.ws.rs.Path;
import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.Response;
import org.eclipse.microprofile.config.Config;
import org.eclipse.microprofile.reactive.messaging.Acknowledgment;
import org.eclipse.microprofile.reactive.messaging.Channel;
import org.eclipse.microprofile.reactive.messaging.Emitter;
import org.eclipse.microprofile.reactive.messaging.Incoming;
import org.eclipse.microprofile.reactive.messaging.Message;
import org.eclipse.microprofile.reactive.messaging.Outgoing;
import org.eclipse.microprofile.reactive.messaging.spi.Connector;
import org.eclipse.microprofile.reactive.messaging.spi.IncomingConnectorFactory;
import org.eclipse.microprofile.reactive.messaging.spi.OutgoingConnectorFactory;
import org.eclipse.microprofile.reactive.streams.operators.PublisherBuilder;
import org.eclipse.microprofile.reactive.streams.operators.ReactiveStreams;
import org.eclipse.microprofile.reactive.streams.operators.SubscriberBuilder;
import org.reactivestreams.Processor;
import org.reactivestreams.Publisher;
import org.reactivestreams.Subscriber;
@SuppressWarnings("ALL")
class IntroductionSnippets {
class Snippet1 {
// tag::snippet_1[]
@Incoming("example-channel-2")
public void printMessage(String msg) {
System.out.println("Just received message: " + msg);
}
// end::snippet_1[]
}
class Snippet2 {
// tag::snippet_2[]
@Incoming("example-channel-2")
public Subscriber printMessage() {
return ReactiveStreams.builder()
.forEach(msg -> System.out.println("Just received message: " + msg))
.build();
}
// end::snippet_2[]
}
class Snippet3 {
class MyBean {
// tag::snippet_3[]
@Inject
public MyBean(@Channel("example-channel-1") Multi multiChannel) {
multiChannel
.map(String::toUpperCase)
.forEach(s -> System.out.println("Received " + s));
}
// end::snippet_3[]
}
}
class Snippet4 {
// tag::snippet_4[]
@Outgoing("example-channel-1")
public String produceMessage() {
return "foo";
}
// end::snippet_4[]
}
class Snippet5 {
// tag::snippet_5[]
@Outgoing("example-channel-1")
public Publisher printMessage() {
return ReactiveStreams.of("foo", "bar", "baz").buildRs();
}
// end::snippet_5[]
}
class Snippet6 {
// tag::snippet_6[]
@Inject
@Channel("example-channel-1")
private Emitter emitter;
@PUT
@Path("/sendMessage")
@Consumes(MediaType.TEXT_PLAIN)
public Response sendMessage(final String payload) {
emitter.send(payload);
return Response.ok().build();
}
// end::snippet_6[]
}
class Snippet7 {
// tag::snippet_7[]
@Incoming("example-channel-1")
@Outgoing("example-channel-2")
public String processMessage(String msg) {
return msg.toUpperCase();
}
// end::snippet_7[]
}
class Snippet8 {
// tag::snippet_8[]
@Incoming("example-channel-1")
@Outgoing("example-channel-2")
public Processor processMessage() {
return ReactiveStreams.builder()
.map(String::toUpperCase)
.buildRs();
}
// end::snippet_8[]
}
class Snippet9 {
// tag::snippet_9[]
@Incoming("example-channel-1")
@Outgoing("example-channel-2")
public Publisher processMessage(String msg) {
return ReactiveStreams.of(msg.toUpperCase(), msg.toLowerCase()).buildRs();
}
// end::snippet_9[]
}
// tag::snippet_10[]
@ApplicationScoped
@Connector("example-connector")
public class ExampleConnector implements IncomingConnectorFactory, OutgoingConnectorFactory {
@Override
public PublisherBuilder> getPublisherBuilder(Config config) {
return ReactiveStreams.of("foo", "bar")
.map(Message::of);
}
@Override
public SubscriberBuilder, Void> getSubscriberBuilder(Config config) {
return ReactiveStreams.>builder()
.map(Message::getPayload)
.forEach(o -> System.out.println("Connector says: " + o));
}
}
// end::snippet_10[]
class Snippet11 {
// tag::snippet_11[]
@Outgoing("publisher-payload")
public PublisherBuilder streamOfMessages() {
return ReactiveStreams.of(0, 1, 2, 3, 4, 5, 6, 7, 8, 9);
}
@Incoming("publisher-payload")
@Outgoing("wrapped-message")
public Message rewrapMessageManually(Message message) {
return Message.of(Integer.toString(message.getPayload()));
}
@Incoming("wrapped-message")
public void consumeImplicitlyUnwrappedMessage(String value) {
System.out.println("Consuming message: " + value);
}
// end::snippet_11[]
}
class Snippet12 {
// tag::snippet_12[]
@Outgoing("consume-and-ack")
public Publisher> streamOfMessages() {
return ReactiveStreams.of(Message.of("This is Payload", () -> {
System.out.println("This particular message was acked!");
return CompletableFuture.completedFuture(null);
})).buildRs();
}
@Incoming("consume-and-ack")
@Acknowledgment(Acknowledgment.Strategy.MANUAL)
public CompletionStage receiveAndAckMessage(Message msg) {
return msg.ack(); //<1>
}
// end::snippet_12[]
}
class Snippet13 {
// tag::snippet_13[]
@Outgoing("consume-and-ack")
public Publisher> streamOfMessages() {
return ReactiveStreams.of(Message.of("This is Payload", () -> {
System.out.println("This particular message was acked!");
return CompletableFuture.completedFuture(null);
})).buildRs();
}
@Incoming("consume-and-ack")
@Acknowledgment(Acknowledgment.Strategy.MANUAL)
public CompletionStage receiveAndAckMessage(Message msg) {
return msg.ack(); //<1>
}
}
// end::snippet_13[]
class Snippet14 {
// tag::snippet_14[]
@Outgoing("consume-and-ack")
public Publisher> streamOfMessages() {
return ReactiveStreams.of(Message.of("This is Payload", () -> {
System.out.println("This particular message was acked!");
return CompletableFuture.completedFuture(null);
})).buildRs();
}
/**
* Prints to the console:
* > This particular message was acked!
* > Method invocation!
*/
@Incoming("consume-and-ack")
@Acknowledgment(Acknowledgment.Strategy.PRE_PROCESSING)
public CompletionStage receiveAndAckMessage(Message msg) {
System.out.println("Method invocation!");
return CompletableFuture.completedFuture(null);
}
// end::snippet_14[]
}
class Snippet15 {
// tag::snippet_15[]
@Outgoing("consume-and-ack")
public Publisher> streamOfMessages() {
return ReactiveStreams.of(Message.of("This is Payload", () -> {
System.out.println("This particular message was acked!");
return CompletableFuture.completedFuture(null);
})).buildRs();
}
/**
* Prints to the console:
* > Method invocation!
* > This particular message was acked!
*/
@Incoming("consume-and-ack")
@Acknowledgment(Acknowledgment.Strategy.POST_PROCESSING)
public CompletionStage receiveAndAckMessage(Message msg) {
System.out.println("Method invocation!");
return CompletableFuture.completedFuture(null);
}
// end::snippet_15[]
}
class Snippet16 {
// tag::snippet_16[]
@Outgoing("to-connector-channel")
public Publisher produce() {
return ReactiveStreams.of("fee", "fie").buildRs();
}
// > Connector says: fee
// > Connector says: fie
// end::snippet_16[]
}
class Snippet17 {
// tag::snippet_17[]
@Incoming("from-connector-channel")
public void consume(String value) {
System.out.println("Consuming: " + value);
}
// >Consuming:foo
// >Consuming:bar
// end::snippet_17[]
}
class Snippet18 {
// tag::snippet_18[]
@ApplicationScoped
@Connector("example-connector")
public class ExampleConnector implements IncomingConnectorFactory {
@Override
public PublisherBuilder> getPublisherBuilder(final Config config) {
String firstPropValue = config.getValue("channel-specific-prop", String.class); // <1>
String secondPropValue = config.getValue("connector-specific-prop", String.class);
String channelName = config.getValue("channel-name", String.class); // <2>
return ReactiveStreams.of(firstPropValue, secondPropValue)
.map(Message::of);
}
}
// end::snippet_18[]
}
class Snippet19 {
// tag::snippet_19[]
@Incoming("from-connector-channel")
public void consume(String value) {
System.out.println("Consuming: " + value);
}
// > Consuming: foo
// > Consuming: bar
// end::snippet_19[]
}
}
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