GH-2159 - Neo4jClient support for database selection.

This also eliminates the need for the database selection definition
in the (Reactive)Neo4jTemplate.

Author: meistermeier

src/main/java/org/springframework/data/neo4j/config/AbstractNeo4jConfig.java

@@ -54,15 +54,14 @@ public abstract class AbstractNeo4jConfig extends Neo4jConfigurationSupport {
 	 * @return A imperative Neo4j client.
 	 */
 	@Bean(Neo4jRepositoryConfigurationExtension.DEFAULT_NEO4J_CLIENT_BEAN_NAME)
-	public Neo4jClient neo4jClient(Driver driver) {
-		return Neo4jClient.create(driver);
+	public Neo4jClient neo4jClient(Driver driver, DatabaseSelectionProvider databaseSelectionProvider) {
+		return Neo4jClient.create(driver, databaseSelectionProvider);
 	}
 
 	@Bean(Neo4jRepositoryConfigurationExtension.DEFAULT_NEO4J_TEMPLATE_BEAN_NAME)
-	public Neo4jOperations neo4jTemplate(final Neo4jClient neo4jClient, final Neo4jMappingContext mappingContext,
-			DatabaseSelectionProvider databaseNameProvider) {
+	public Neo4jOperations neo4jTemplate(final Neo4jClient neo4jClient, final Neo4jMappingContext mappingContext) {
 
-		return new Neo4jTemplate(neo4jClient, mappingContext, databaseNameProvider);
+		return new Neo4jTemplate(neo4jClient, mappingContext);
 	}
 
 	/**

src/main/java/org/springframework/data/neo4j/config/AbstractReactiveNeo4jConfig.java

@@ -60,9 +60,9 @@ public ReactiveNeo4jClient neo4jClient(Driver driver) {
 
 	@Bean(ReactiveNeo4jRepositoryConfigurationExtension.DEFAULT_NEO4J_TEMPLATE_BEAN_NAME)
 	public ReactiveNeo4jTemplate neo4jTemplate(final ReactiveNeo4jClient neo4jClient,
-			final Neo4jMappingContext mappingContext, final ReactiveDatabaseSelectionProvider databaseNameProvider) {
+			final Neo4jMappingContext mappingContext) {
 
-		return new ReactiveNeo4jTemplate(neo4jClient, mappingContext, databaseNameProvider);
+		return new ReactiveNeo4jTemplate(neo4jClient, mappingContext);
 	}
 
 	/**

src/main/java/org/springframework/data/neo4j/config/Neo4jCdiConfigurationSupport.java

@@ -15,12 +15,6 @@
  */
 package org.springframework.data.neo4j.config;
 
-import javax.enterprise.context.ApplicationScoped;
-import javax.enterprise.inject.Any;
-import javax.enterprise.inject.Instance;
-import javax.enterprise.inject.Produces;
-import javax.inject.Singleton;
-
 import org.apiguardian.api.API;
 import org.neo4j.driver.Driver;
 import org.springframework.data.neo4j.core.DatabaseSelectionProvider;
@@ -32,6 +26,12 @@
 import org.springframework.data.neo4j.core.transaction.Neo4jTransactionManager;
 import org.springframework.transaction.PlatformTransactionManager;
 
+import javax.enterprise.context.ApplicationScoped;
+import javax.enterprise.inject.Any;
+import javax.enterprise.inject.Instance;
+import javax.enterprise.inject.Produces;
+import javax.inject.Singleton;
+
 /**
  * Support class that can be used as is for all necessary CDI beans or as a blueprint for custom producers.
  *
@@ -66,10 +66,9 @@ public DatabaseSelectionProvider databaseSelectionProvider() {
 	@Produces @Builtin @Singleton
 	public Neo4jOperations neo4jOperations(
 			@Any Instance<Neo4jClient> neo4jClient,
-			@Any Instance<Neo4jMappingContext> mappingContext,
-			@Any Instance<DatabaseSelectionProvider> databaseNameProvider
+			@Any Instance<Neo4jMappingContext> mappingContext
 	) {
-		return new Neo4jTemplate(resolve(neo4jClient), resolve(mappingContext), resolve(databaseNameProvider));
+		return new Neo4jTemplate(resolve(neo4jClient), resolve(mappingContext));
 	}
 
 	@Produces @Singleton

src/main/java/org/springframework/data/neo4j/core/DefaultNeo4jClient.java

@@ -56,13 +56,15 @@ class DefaultNeo4jClient implements Neo4jClient {
 
 	private final Driver driver;
 	private final TypeSystem typeSystem;
+	private final DatabaseSelectionProvider databaseSelectionProvider;
 	private final ConversionService conversionService;
 	private final Neo4jPersistenceExceptionTranslator persistenceExceptionTranslator = new Neo4jPersistenceExceptionTranslator();
 
-	DefaultNeo4jClient(Driver driver) {
+	DefaultNeo4jClient(Driver driver, DatabaseSelectionProvider databaseSelectionProvider) {
 
 		this.driver = driver;
 		this.typeSystem = driver.defaultTypeSystem();
+		this.databaseSelectionProvider = databaseSelectionProvider;
 
 		this.conversionService = new DefaultConversionService();
 		new Neo4jConversions().registerConvertersIn((ConverterRegistry) conversionService);
@@ -262,7 +264,11 @@ class DefaultRecordFetchSpec<T> implements RecordFetchSpec<T>, MappingSpec<T> {
 
 		DefaultRecordFetchSpec(String targetDatabase, RunnableStatement runnableStatement,
 				BiFunction<TypeSystem, Record, T> mappingFunction) {
-			this.targetDatabase = targetDatabase;
+			this.targetDatabase = targetDatabase != null
+					? targetDatabase
+					: databaseSelectionProvider != null
+						? databaseSelectionProvider.getDatabaseSelection().getValue()
+						: null;
 			this.runnableStatement = runnableStatement;
 			this.mappingFunction = mappingFunction;
 		}

src/main/java/org/springframework/data/neo4j/core/DefaultReactiveNeo4jClient.java

@@ -15,15 +15,6 @@
  */
 package org.springframework.data.neo4j.core;
 
-import reactor.core.publisher.Flux;
-import reactor.core.publisher.Mono;
-import reactor.util.function.Tuple2;
-
-import java.util.Map;
-import java.util.function.BiFunction;
-import java.util.function.Function;
-import java.util.function.Supplier;
-
 import org.neo4j.driver.Driver;
 import org.neo4j.driver.Record;
 import org.neo4j.driver.reactive.RxQueryRunner;
@@ -41,6 +32,14 @@
 import org.springframework.data.neo4j.core.transaction.ReactiveNeo4jTransactionManager;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+import reactor.util.function.Tuple2;
+
+import java.util.Map;
+import java.util.function.BiFunction;
+import java.util.function.Function;
+import java.util.function.Supplier;
 
 /**
  * Reactive variant of the {@link Neo4jClient}.
@@ -54,13 +53,15 @@ class DefaultReactiveNeo4jClient implements ReactiveNeo4jClient {
 
 	private final Driver driver;
 	private final TypeSystem typeSystem;
+	private final ReactiveDatabaseSelectionProvider databaseSelectionProvider;
 	private final ConversionService conversionService;
 	private final Neo4jPersistenceExceptionTranslator persistenceExceptionTranslator = new Neo4jPersistenceExceptionTranslator();
 
-	DefaultReactiveNeo4jClient(Driver driver) {
+	DefaultReactiveNeo4jClient(Driver driver, @Nullable ReactiveDatabaseSelectionProvider databaseSelectionProvider) {
 
 		this.driver = driver;
 		this.typeSystem = driver.defaultTypeSystem();
+		this.databaseSelectionProvider = databaseSelectionProvider;
 		this.conversionService = new DefaultConversionService();
 		new Neo4jConversions().registerConvertersIn((ConverterRegistry) conversionService);
 	}
@@ -180,7 +181,7 @@ public Mono<ResultSummary> run() {
 
 	class DefaultRecordFetchSpec<T> implements RecordFetchSpec<T>, MappingSpec<T> {
 
-		private final String targetDatabase;
+		private final Mono<DatabaseSelection> targetDatabase;
 
 		private final Supplier<String> cypherSupplier;
 
@@ -192,9 +193,18 @@ class DefaultRecordFetchSpec<T> implements RecordFetchSpec<T>, MappingSpec<T> {
 			this(targetDatabase, cypherSupplier, parameters, null);
 		}
 
-		DefaultRecordFetchSpec(String targetDatabase, Supplier<String> cypherSupplier, NamedParameters parameters,
+		DefaultRecordFetchSpec(@Nullable String targetDatabase, Supplier<String> cypherSupplier, NamedParameters parameters,
 				@Nullable BiFunction<TypeSystem, Record, T> mappingFunction) {
-			this.targetDatabase = targetDatabase;
+
+			this.targetDatabase = Mono.defer(() -> {
+				if (targetDatabase != null) {
+					return ReactiveDatabaseSelectionProvider.createStaticDatabaseSelectionProvider(targetDatabase)
+							.getDatabaseSelection();
+				} else if (databaseSelectionProvider != null) {
+					return databaseSelectionProvider.getDatabaseSelection();
+				}
+				return Mono.just(DatabaseSelection.undecided());
+			});
 			this.cypherSupplier = cypherSupplier;
 			this.parameters = parameters;
 			this.mappingFunction = mappingFunction;
@@ -229,33 +239,36 @@ Flux<T> executeWith(Tuple2<String, Map<String, Object>> t, RxQueryRunner runner)
 		@Override
 		public Mono<T> one() {
 
-			return doInQueryRunnerForMono(targetDatabase,
-					(runner) -> prepareStatement().flatMapMany(t -> executeWith(t, runner)).singleOrEmpty())
+			return targetDatabase.flatMap(databaseSelection -> doInQueryRunnerForMono(databaseSelection.getValue(),
+					(runner) -> prepareStatement().flatMapMany(t -> executeWith(t, runner)).singleOrEmpty()))
 							.onErrorMap(RuntimeException.class, DefaultReactiveNeo4jClient.this::potentiallyConvertRuntimeException);
 		}
 
 		@Override
 		public Mono<T> first() {
 
-			return doInQueryRunnerForMono(targetDatabase,
-					runner -> prepareStatement().flatMapMany(t -> executeWith(t, runner)).next())
+			return targetDatabase.flatMap(databaseSelection -> doInQueryRunnerForMono(databaseSelection.getValue(),
+					runner -> prepareStatement().flatMapMany(t -> executeWith(t, runner)).next()))
 							.onErrorMap(RuntimeException.class, DefaultReactiveNeo4jClient.this::potentiallyConvertRuntimeException);
 		}
 
 		@Override
 		public Flux<T> all() {
 
-			return doInStatementRunnerForFlux(targetDatabase,
-					runner -> prepareStatement().flatMapMany(t -> executeWith(t, runner))).onErrorMap(RuntimeException.class,
-							DefaultReactiveNeo4jClient.this::potentiallyConvertRuntimeException);
+			return targetDatabase.flatMapMany(databaseSelection ->
+					doInStatementRunnerForFlux(databaseSelection.getValue(),
+						runner -> prepareStatement().flatMapMany(t -> executeWith(t, runner)))
+					)
+					.onErrorMap(RuntimeException.class,	DefaultReactiveNeo4jClient.this::potentiallyConvertRuntimeException);
 		}
 
 		Mono<ResultSummary> run() {
 
-			return doInQueryRunnerForMono(targetDatabase, runner -> prepareStatement().flatMap(t -> {
-				RxResult rxResult = runner.run(t.getT1(), t.getT2());
-				return Flux.from(rxResult.records()).then(Mono.from(rxResult.consume()).map(ResultSummaries::process));
-			})).onErrorMap(RuntimeException.class, DefaultReactiveNeo4jClient.this::potentiallyConvertRuntimeException);
+			return targetDatabase.flatMap(databaseSelection ->
+					doInQueryRunnerForMono(databaseSelection.getValue(), runner -> prepareStatement().flatMap(t -> {
+						RxResult rxResult = runner.run(t.getT1(), t.getT2());
+						return Flux.from(rxResult.records()).then(Mono.from(rxResult.consume()).map(ResultSummaries::process));
+			}))).onErrorMap(RuntimeException.class, DefaultReactiveNeo4jClient.this::potentiallyConvertRuntimeException);
 		}
 	}
 

src/main/java/org/springframework/data/neo4j/core/Neo4jClient.java

@@ -48,7 +48,12 @@ public interface Neo4jClient {
 
 	static Neo4jClient create(Driver driver) {
 
-		return new DefaultNeo4jClient(driver);
+		return new DefaultNeo4jClient(driver, null);
+	}
+
+	static Neo4jClient create(Driver driver, DatabaseSelectionProvider databaseSelectionProvider) {
+
+		return new DefaultNeo4jClient(driver, databaseSelectionProvider);
 	}
 
 	/**