Add an example how to use custom resolver functions.

Author: michael-simons

examples/dedicated-routing-driver/src/main/java/org/neo4j/doc/driver/springframework/boot/dedicated_routing_driver/DriverWithCustomResolverFunctionConfiguration.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (c) 2019-2020 "Neo4j,"
+ * Neo4j Sweden AB [https://neo4j.com]
+ *
+ * This file is part of Neo4j.
+ *
+ * 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
+ *
+ *     https://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 org.neo4j.doc.driver.springframework.boot.dedicated_routing_driver;
+
+import java.util.Arrays;
+import java.util.HashSet;
+
+import org.neo4j.driver.AuthToken;
+import org.neo4j.driver.Config;
+import org.neo4j.driver.Driver;
+import org.neo4j.driver.GraphDatabase;
+import org.neo4j.driver.net.ServerAddress;
+import org.neo4j.driver.springframework.boot.autoconfigure.Neo4jDriverProperties;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Profile;
+
+/**
+ * This is a setup for the solution proposeed in the official driver docs:
+ * <a href="https://neo4j.com/docs/driver-manual/current/client-applications/#driver-resolver-function">2.2.1.3. Resolver function</a>
+ */
+// This is just here to prevent both this configuration and RoutingDriverConfiguration to run in parallel.
+@Profile("custom-resolver-function")
+
+@Configuration
+public class DriverWithCustomResolverFunctionConfiguration {
+
+	@Bean
+	public Driver neo4jDriver(Neo4jDriverProperties neo4jDriverProperties) {
+
+		Config config = Config.builder()
+			.withResolver(address -> {
+				if ("datacenter1".equals(address.host())) {
+					return new HashSet<>(
+						Arrays.asList(ServerAddress.of("dc1-core1", 7687), ServerAddress.of("dc1-core2", 7687)));
+				} else {
+					return new HashSet<>(Arrays.asList(ServerAddress.of("other-core", 7687)));
+				}
+			}).build();
+		AuthToken authToken = neo4jDriverProperties.getAuthToken();
+
+		return GraphDatabase.driver(neo4jDriverProperties.getUri(), authToken, config);
+	}
+}