GH-2888 - Respect multiple Neo4jTransactionManagers.

There might be different transaction managers in place for different
Neo4jTemplates.

The change is also applied to the ReactiveNeo4jTemplate.

Co-authored-by: Michael Simons <[email protected]>

Author: meistermeier

src/main/java/org/springframework/data/neo4j/core/Neo4jTemplate.java

@@ -158,8 +158,17 @@ public Neo4jTemplate(Neo4jClient neo4jClient, Neo4jMappingContext neo4jMappingCo
 		this(neo4jClient, neo4jMappingContext, EntityCallbacks.create());
 	}
 
+	public Neo4jTemplate(Neo4jClient neo4jClient, Neo4jMappingContext neo4jMappingContext, PlatformTransactionManager transactionManager) {
+		this(neo4jClient, neo4jMappingContext, EntityCallbacks.create(), transactionManager);
+	}
+
 	public Neo4jTemplate(Neo4jClient neo4jClient, Neo4jMappingContext neo4jMappingContext,
 						 EntityCallbacks entityCallbacks) {
+		this(neo4jClient, neo4jMappingContext, entityCallbacks, null);
+	}
+
+	public Neo4jTemplate(Neo4jClient neo4jClient, Neo4jMappingContext neo4jMappingContext,
+						 EntityCallbacks entityCallbacks, @Nullable PlatformTransactionManager platformTransactionManager) {
 
 		Assert.notNull(neo4jClient, "The Neo4jClient is required");
 		Assert.notNull(neo4jMappingContext, "The Neo4jMappingContext is required");
@@ -170,6 +179,7 @@ public Neo4jTemplate(Neo4jClient neo4jClient, Neo4jMappingContext neo4jMappingCo
 		this.eventSupport = EventSupport.useExistingCallbacks(neo4jMappingContext, entityCallbacks);
 		this.renderer = Renderer.getDefaultRenderer();
 		this.elementIdOrIdFunction = SpringDataCypherDsl.elementIdOrIdFunction.apply(null);
+		setTransactionManager(platformTransactionManager);
 	}
 
 	ProjectionFactory getProjectionFactory() {
@@ -1102,20 +1112,35 @@ public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
 		this.elementIdOrIdFunction = SpringDataCypherDsl.elementIdOrIdFunction.apply(cypherDslConfiguration.getDialect());
 		this.cypherGenerator.setElementIdOrIdFunction(elementIdOrIdFunction);
 
-		PlatformTransactionManager transactionManager = beanFactory.getBeanProvider(PlatformTransactionManager.class).getIfUnique(() -> beanFactory.getBean(Neo4jTransactionManager.class));
-		this.transactionTemplate = new TransactionTemplate(transactionManager);
-		this.transactionTemplateReadOnly = new TransactionTemplate(transactionManager, readOnlyTransactionDefinition);
+		if (this.transactionTemplate != null && this.transactionTemplateReadOnly != null) {
+			return;
+		}
+		PlatformTransactionManager transactionManager = null;
+		var it = beanFactory.getBeanProvider(PlatformTransactionManager.class).stream().iterator();
+		while (it.hasNext()) {
+			PlatformTransactionManager transactionManagerCandidate = it.next();
+			if (transactionManagerCandidate instanceof Neo4jTransactionManager neo4jTransactionManager) {
+				if (transactionManager != null) {
+					throw new IllegalStateException("Multiple Neo4jTransactionManagers are defined in this context. " +
+							"If this in intended, please pass the transaction manager to use with this Neo4jTemplate in the constructor");
+				}
+				transactionManager = neo4jTransactionManager;
+			}
+		}
+		setTransactionManager(transactionManager);
 	}
 
 	// only used for the CDI configuration
 	public void setCypherRenderer(Renderer rendererFromCdiConfiguration) {
 		this.renderer = rendererFromCdiConfiguration;
 	}
 
-	// only used for the CDI configuration
-	public void setTransactionManager(PlatformTransactionManager platformTransactionManager) {
-		this.transactionTemplate = new TransactionTemplate(platformTransactionManager);
-		this.transactionTemplateReadOnly = new TransactionTemplate(platformTransactionManager, readOnlyTransactionDefinition);
+	public void setTransactionManager(@Nullable PlatformTransactionManager transactionManager) {
+		if (transactionManager == null) {
+			return;
+		}
+		this.transactionTemplate = new TransactionTemplate(transactionManager);
+		this.transactionTemplateReadOnly = new TransactionTemplate(transactionManager, readOnlyTransactionDefinition);
 	}
 
 	@Override

src/main/java/org/springframework/data/neo4j/core/ReactiveNeo4jTemplate.java

@@ -150,9 +150,14 @@ public boolean isReadOnly() {
 	private ProjectionFactory projectionFactory;
 
 	private Renderer renderer;
+
 	private Function<Named, FunctionInvocation> elementIdOrIdFunction;
 
 	public ReactiveNeo4jTemplate(ReactiveNeo4jClient neo4jClient, Neo4jMappingContext neo4jMappingContext) {
+		this(neo4jClient, neo4jMappingContext, null);
+	}
+
+	public ReactiveNeo4jTemplate(ReactiveNeo4jClient neo4jClient, Neo4jMappingContext neo4jMappingContext, @Nullable ReactiveTransactionManager transactionManager) {
 
 		Assert.notNull(neo4jClient, "The Neo4jClient is required");
 		Assert.notNull(neo4jMappingContext, "The Neo4jMappingContext is required");
@@ -163,6 +168,7 @@ public ReactiveNeo4jTemplate(ReactiveNeo4jClient neo4jClient, Neo4jMappingContex
 		this.eventSupport = ReactiveEventSupport.useExistingCallbacks(neo4jMappingContext, ReactiveEntityCallbacks.create());
 		this.renderer = Renderer.getDefaultRenderer();
 		this.elementIdOrIdFunction = SpringDataCypherDsl.elementIdOrIdFunction.apply(null);
+		setTransactionManager(transactionManager);
 	}
 
 	ProjectionFactory getProjectionFactory() {
@@ -1182,10 +1188,32 @@ public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
 		this.renderer = Renderer.getRenderer(cypherDslConfiguration);
 		this.elementIdOrIdFunction = SpringDataCypherDsl.elementIdOrIdFunction.apply(cypherDslConfiguration.getDialect());
 		this.cypherGenerator.setElementIdOrIdFunction(elementIdOrIdFunction);
-		ReactiveTransactionManager reactiveTransactionManager = beanFactory.getBeanProvider(ReactiveTransactionManager.class)
-				.getIfUnique(() -> beanFactory.getBean(ReactiveNeo4jTransactionManager.class));
-		this.transactionalOperatorReadOnly = TransactionalOperator.create(reactiveTransactionManager, readOnlyTransactionDefinition);
+
+		if (this.transactionalOperator != null && this.transactionalOperatorReadOnly != null) {
+			return;
+		}
+
+		ReactiveTransactionManager reactiveTransactionManager = null;
+		var iter = beanFactory.getBeanProvider(ReactiveTransactionManager.class).stream().iterator();
+		while (iter.hasNext()) {
+			ReactiveTransactionManager transactionManagerCandidate = iter.next();
+			if (transactionManagerCandidate instanceof ReactiveNeo4jTransactionManager reactiveNeo4jTransactionManager) {
+				if (reactiveTransactionManager != null) {
+					throw new IllegalStateException("Multiple ReactiveNeo4jTransactionManagers are defined in this context. " +
+							"If this in intended, please pass the transaction manager to use with this ReactiveNeo4jTemplate in the constructor");
+				}
+				reactiveTransactionManager = reactiveNeo4jTransactionManager;
+			}
+		}
+		setTransactionManager(reactiveTransactionManager);
+	}
+
+	private void setTransactionManager(@Nullable ReactiveTransactionManager reactiveTransactionManager) {
+		if (reactiveTransactionManager == null) {
+			return;
+		}
 		this.transactionalOperator = TransactionalOperator.create(reactiveTransactionManager);
+		this.transactionalOperatorReadOnly = TransactionalOperator.create(reactiveTransactionManager, readOnlyTransactionDefinition);
 	}
 
 	@Override

src/test/java/org/springframework/data/neo4j/integration/multiple_ctx_imperative/domain1/Domain1Config.java

@@ -63,9 +63,10 @@ public Neo4jClient domain1Client(@Qualifier("domain1Driver") Driver driver) {
 	@Primary @Bean
 	public Neo4jOperations domain1Template(
 			@Qualifier("domain1Client") Neo4jClient domain1Client,
-			@Qualifier("domain1Context") Neo4jMappingContext domain1Context
+			@Qualifier("domain1Context") Neo4jMappingContext domain1Context,
+			@Qualifier("domain1Manager") PlatformTransactionManager domain1TransactionManager
 	) {
-		return new Neo4jTemplate(domain1Client, domain1Context);
+		return new Neo4jTemplate(domain1Client, domain1Context, domain1TransactionManager);
 	}
 
 	@Primary @Bean
@@ -78,7 +79,7 @@ public PlatformTransactionManager domain1Manager(
 
 	@Primary @Bean
 	public DatabaseSelectionProvider domain1Selection() {
-		return () -> DatabaseSelection.undecided();
+		return DatabaseSelection::undecided;
 	}
 
 	@Primary @Bean

src/test/java/org/springframework/data/neo4j/integration/multiple_ctx_imperative/domain2/Domain2Config.java

@@ -62,9 +62,10 @@ public Neo4jClient domain2Client(@Qualifier("domain2Driver") Driver driver) {
 	@Bean
 	public Neo4jOperations domain2Template(
 			@Qualifier("domain2Client") Neo4jClient domain2Client,
-			@Qualifier("domain2Context") Neo4jMappingContext domain2Context
+			@Qualifier("domain2Context") Neo4jMappingContext domain2Context,
+			@Qualifier("domain2Manager") PlatformTransactionManager domain2TransactionManager
 	) {
-		return new Neo4jTemplate(domain2Client, domain2Context);
+		return new Neo4jTemplate(domain2Client, domain2Context, domain2TransactionManager);
 	}
 
 	@Bean
@@ -77,7 +78,7 @@ public PlatformTransactionManager domain2Manager(
 
 	@Bean
 	public DatabaseSelectionProvider domain2Selection() {
-		return () -> DatabaseSelection.undecided();
+		return DatabaseSelection::undecided;
 	}
 
 	@Bean