From 13ea2d9111c89c25bda2723e12935edce3348886 Mon Sep 17 00:00:00 2001
From: Artem Bilan <abilan@pivotal.io>
Date: Sat, 1 Nov 2014 13:11:17 +0200
Subject: [PATCH] DSL: Fix `RouterSpec` for several subflows

The root of the issue is the order of bean registration in the beanFactory.
In this case the first subflows is registered correctly, but the next one has been registered after `RouterSubFlowMappingProvider`.
In this case the input `channel` of the next subflow hasn't been registered yet, hence `NPE` in the `this.router.setChannelMapping`
from `@PostConstruct` of `RouterSubFlowMappingProvider`.

Move the `RouterSubFlowMappingProvider` to end of `componentsToRegister` collection to give a chance to register all subflows before the `RouterSubFlowMappingProvider`.
---
 .../integration/dsl/RouterSpec.java           |  4 ++-
 .../dsl/test/flows/IntegrationFlowTests.java  | 33 +++++++++++++++++++
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/RouterSpec.java b/spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/RouterSpec.java
index 1a610a1..b642934 100644
--- a/spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/RouterSpec.java
+++ b/spring-integration-java-dsl/src/main/java/org/springframework/integration/dsl/RouterSpec.java
@@ -90,7 +90,6 @@ public final class RouterSpec<R extends AbstractMappingMessageRouter> extends Ab
 
 		if (this.mappingProvider == null) {
 			this.mappingProvider = new RouterSubFlowMappingProvider(this.target);
-			this.subFlows.add(this.mappingProvider);
 		}
 		this.mappingProvider.addMapping(key, channel);
 		return _this();
@@ -98,6 +97,9 @@ public final class RouterSpec<R extends AbstractMappingMessageRouter> extends Ab
 
 	@Override
 	public Collection<Object> getComponentsToRegister() {
+		if (this.mappingProvider != null) {
+			this.subFlows.add(this.mappingProvider);
+		}
 		return this.subFlows;
 	}
 
diff --git a/spring-integration-java-dsl/src/test/java/org/springframework/integration/dsl/test/flows/IntegrationFlowTests.java b/spring-integration-java-dsl/src/test/java/org/springframework/integration/dsl/test/flows/IntegrationFlowTests.java
index bf54125..7b89955 100644
--- a/spring-integration-java-dsl/src/test/java/org/springframework/integration/dsl/test/flows/IntegrationFlowTests.java
+++ b/spring-integration-java-dsl/src/test/java/org/springframework/integration/dsl/test/flows/IntegrationFlowTests.java
@@ -18,6 +18,7 @@ package org.springframework.integration.dsl.test.flows;
 
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.instanceOf;
+import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
@@ -563,7 +564,27 @@ public class IntegrationFlowTests {
 			assertNotNull(receive);
 			assertEquals(payloads[i * 2 + 1], receive.getPayload());
 		}
+	}
 
+	@Autowired
+	@Qualifier("routerTwoSubFlows.input")
+	private MessageChannel routerTwoSubFlowsInput;
+
+	@Autowired
+	@Qualifier("routerTwoSubFlowsOutput")
+	private PollableChannel routerTwoSubFlowsOutput;
+
+	@Test
+	public void testRouterWithTwoSubflows() {
+		this.routerTwoSubFlowsInput.send(new GenericMessage<Object>(Arrays.asList(1, 2, 3, 4, 5, 6)));
+		Message<?> receive = this.routerTwoSubFlowsOutput.receive(5000);
+		assertNotNull(receive);
+		Object payload = receive.getPayload();
+		assertThat(payload, instanceOf(List.class));
+		@SuppressWarnings("unchecked")
+		List<Integer> results = (List<Integer>) payload;
+
+		assertArrayEquals(new Integer[] {3, 4, 9, 8, 15, 12}, results.toArray(new Integer[results.size()]));
 	}
 
 	@Test
@@ -1191,6 +1212,18 @@ public class IntegrationFlowTests {
 					.get();
 		}
 
+
+		@Bean
+		public IntegrationFlow routerTwoSubFlows() {
+			return f -> f
+					.split()
+					.<Integer, Boolean>route(p -> p % 2 == 0, m -> m
+							.subFlowMapping("true", sf -> sf.<Integer>handle((p, h) -> p * 2))
+							.subFlowMapping("false", sf -> sf.<Integer>handle((p, h) -> p * 3)))
+					.aggregate()
+					.channel(c -> c.queue("routerTwoSubFlowsOutput"));
+		}
+
 		@Bean
 		public RoutingTestBean routingTestBean() {
 			return new RoutingTestBean();