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Introduce high-level API for flows composition (#3624)

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* Introduce high-level API for flows composition

For better end-user experience and more smooth integration logic
decomposition and distribution introduce an `IntegrationFlows.from(IntegrationFlow)`
to let to start the current flow from existing one.
On the other hand introduce an `BaseIntegrationFlowDefinition.to(IntegrationFlow)`
to let to continue the flow logic in the other existing one.
This way we can extract some templating logic into separate `IntegrationFlow` definitions
allowing at the same time to decompose a complex flow definition into logical reusable parts

* * Add more tests

* * Fix Checkstyle violation
* Add `@SuppressWarnings("overloads")` to new `from(IntegrationFlow)` and existing `from(Publisher)`.
Technically it does not make sense since `PublisherIntegrationFlow` is not a `public` class

* * Add docs
* Fix language in JavaDocs according review

* Fix language in the docs after review

Co-authored-by: Gary Russell <grussell@vmware.com>

Co-authored-by: Gary Russell <grussell@vmware.com>
This commit is contained in:
Artem Bilan
2021-09-08 17:14:29 -04:00
committed by GitHub
parent b8785e5f9c
commit 4456caffa1
10 changed files with 379 additions and 4 deletions
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4
spring-integration-core/src/main/java/org/springframework/integration/config/ConsumerEndpointFactoryBean.java
View File

@@ -137,6 +137,10 @@ public class ConsumerEndpointFactoryBean
}
}
public MessageHandler getHandler() {
return this.handler;
}
public void setInputChannel(MessageChannel inputChannel) {
this.inputChannel = inputChannel;
}

12
spring-integration-core/src/main/java/org/springframework/integration/dsl/BaseIntegrationFlowDefinition.java
View File

@@ -2917,6 +2917,18 @@ public abstract class BaseIntegrationFlowDefinition<B extends BaseIntegrationFlo
.get();
}
/**
* Finish this flow with delegation to other {@link IntegrationFlow} instance.
* @param other the {@link IntegrationFlow} to compose with.
* @return The {@link IntegrationFlow} instance based on this definition.
* @since 5.5.4
*/
public IntegrationFlow to(IntegrationFlow other) {
MessageChannel otherFlowInputChannel = obtainInputChannelFromFlow(other);
return channel(otherFlowInputChannel)
.get();
}
/**
* Represent an Integration Flow as a Reactive Streams {@link Publisher} bean.
* @param <T> the expected {@code payload} type

13
spring-integration-core/src/main/java/org/springframework/integration/dsl/IntegrationFlow.java
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@@ -1,5 +1,5 @@
/*
* Copyright 2016-2019 the original author or authors.
* Copyright 2016-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -16,6 +16,8 @@
package org.springframework.integration.dsl;
import java.util.Map;
import org.springframework.messaging.MessageChannel;
/**
@@ -92,4 +94,13 @@ public interface IntegrationFlow {
return null;
}
/**
* Return a map of integration components managed by this flow (if any).
* @return the map of integration components managed by this flow.
* @since 5.5.4
*/
default Map<Object, String> getIntegrationComponents() {
return null;
}
}

7
spring-integration-core/src/main/java/org/springframework/integration/dsl/IntegrationFlowAdapter.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2016-2020 the original author or authors.
* Copyright 2016-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@
package org.springframework.integration.dsl;
import java.util.Map;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Consumer;
import java.util.function.Supplier;
@@ -79,6 +80,10 @@ public abstract class IntegrationFlowAdapter implements IntegrationFlow, Managea
return this.targetIntegrationFlow.getInputChannel();
}
@Override public Map<Object, String> getIntegrationComponents() {
return this.targetIntegrationFlow.getIntegrationComponents();
}
@Override
public void start() {
assertTargetIntegrationFlow();

61
spring-integration-core/src/main/java/org/springframework/integration/dsl/IntegrationFlows.java
View File

@@ -16,22 +16,29 @@
package org.springframework.integration.dsl;
import java.util.Map;
import java.util.function.Consumer;
import java.util.function.Supplier;
import org.reactivestreams.Publisher;
import org.springframework.aop.framework.Advised;
import org.springframework.beans.factory.BeanCreationException;
import org.springframework.integration.channel.DirectChannel;
import org.springframework.integration.channel.FluxMessageChannel;
import org.springframework.integration.channel.PublishSubscribeChannel;
import org.springframework.integration.config.ConsumerEndpointFactoryBean;
import org.springframework.integration.core.MessageSource;
import org.springframework.integration.dsl.support.FixedSubscriberChannelPrototype;
import org.springframework.integration.dsl.support.MessageChannelReference;
import org.springframework.integration.endpoint.AbstractMessageSource;
import org.springframework.integration.endpoint.MessageProducerSupport;
import org.springframework.integration.gateway.MessagingGatewaySupport;
import org.springframework.integration.handler.AbstractMessageProducingHandler;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageChannel;
import org.springframework.messaging.MessageHandler;
import org.springframework.util.Assert;
/**
@@ -328,12 +335,52 @@ public final class IntegrationFlows {
* @param publisher the {@link Publisher} to subscribe to.
* @return new {@link IntegrationFlowBuilder}.
*/
@SuppressWarnings("overloads")
public static IntegrationFlowBuilder from(Publisher<? extends Message<?>> publisher) {
FluxMessageChannel reactiveChannel = new FluxMessageChannel();
reactiveChannel.subscribeTo(publisher);
return from((MessageChannel) reactiveChannel);
}
/**
* Start the flow with a composition from the {@link IntegrationFlow}.
* @param other the {@link IntegrationFlow} from which to compose.
* @return new {@link IntegrationFlowBuilder}.
* @since 5.5.4
*/
@SuppressWarnings("overloads")
public static IntegrationFlowBuilder from(IntegrationFlow other) {
Map<Object, String> integrationComponents = other.getIntegrationComponents();
Assert.notNull(integrationComponents, () ->
"The provided integration flow to compose from '" + other +
"' must be declared as a bean in the application context");
Object lastIntegrationComponentFromOther =
integrationComponents.keySet().stream().reduce((prev, next) -> next).orElse(null);
if (lastIntegrationComponentFromOther instanceof MessageChannel) {
return from((MessageChannel) lastIntegrationComponentFromOther);
}
else if (lastIntegrationComponentFromOther instanceof ConsumerEndpointFactoryBean) {
MessageHandler handler = ((ConsumerEndpointFactoryBean) lastIntegrationComponentFromOther).getHandler();
handler = extractProxyTarget(handler);
if (handler instanceof AbstractMessageProducingHandler) {
return buildFlowFromOutputChannel((AbstractMessageProducingHandler) handler);
}
lastIntegrationComponentFromOther = handler; // for the exception message below
}
throw new BeanCreationException("The 'IntegrationFlow' to start from must end with " +
"a 'MessageChannel' or reply-producing endpoint to let the result from that flow to be " +
"processed in this instance. The provided flow ends with: " + lastIntegrationComponentFromOther);
}
private static IntegrationFlowBuilder buildFlowFromOutputChannel(AbstractMessageProducingHandler handler) {
MessageChannel outputChannel = handler.getOutputChannel();
if (outputChannel == null) {
outputChannel = new PublishSubscribeChannel();
handler.setOutputChannel(outputChannel);
}
return from(outputChannel);
}
private static IntegrationFlowBuilder from(MessagingGatewaySupport inboundGateway,
@Nullable IntegrationFlowBuilder integrationFlowBuilderArg) {
@@ -360,6 +407,20 @@ public final class IntegrationFlows {
return null;
}
@SuppressWarnings("unchecked")
private static <T> T extractProxyTarget(T target) {
if (!(target instanceof Advised)) {
return target;
}
Advised advised = (Advised) target;
try {
return (T) extractProxyTarget(advised.getTargetSource().getTarget());
}
catch (Exception e) {
throw new BeanCreationException("Could not extract target", e);
}
}
private IntegrationFlows() {
}

3
spring-integration-core/src/main/java/org/springframework/integration/dsl/context/IntegrationFlowBeanPostProcessor.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2016-2020 the original author or authors.
* Copyright 2016-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -321,6 +321,7 @@ public class IntegrationFlowBeanPostProcessor
new NameMatchMethodPointcutAdvisor(new IntegrationFlowLifecycleAdvice(target));
integrationFlowAdvice.setMappedNames(
"getInputChannel",
"getIntegrationComponents",
"start",
"stop",
"isRunning",

8
spring-integration-core/src/main/java/org/springframework/integration/dsl/context/IntegrationFlowLifecycleAdvice.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2018-2019 the original author or authors.
* Copyright 2018-2021 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -75,6 +75,12 @@ class IntegrationFlowLifecycleAdvice implements MethodInterceptor {
result = this.delegate.getInputChannel();
}
}
else if ("getIntegrationComponents".equals(method)) {
result = invocation.proceed();
if (result == null) {
result = this.delegate.getIntegrationComponents();
}
}
else {
if (target instanceof SmartLifecycle) {
result = invocation.proceed();