#421 - Elevate R2DBC example to top level project.

Moved r2dbc example to a top-level project. Switched to new Spring Data R2DBC project coordinates.

Original pull request: #422.

r2dbc/example/README.adoc

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+== Spring Data R2DBC basics
+
+This projects shows some sample usage of the work-in-progress R2DBC support for Spring Data.
+
+=== Requirements
+
+- A PostgreSQL database server running on port 5432, a database instance named `postgres` with a user `postgres` and an empty password.
+
+=== Interesting bits to look at
+
+- `InfrastructureConfiguration` - sets up a R2DBC `ConnectionFactory` based on the R2DBC Postgres driver (https://github.com/r2dbc/r2dbc-postgresql[r2dbc-postgresql]), a `DatabaseClient` and a `R2dbcRepositoryFactory` to eventually create a `CustomerRepository`.
+- `CustomerRepository` - a standard Spring Data reactive CRUD repository exposing query methods using manually defined queries
+- `CustomerRepositoryIntegrationTests` - to initialize the database with some setup SQL and the inserting and reading `Customer` instances.

r2dbc/example/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+	<modelVersion>4.0.0</modelVersion>
+
+	<parent>
+		<groupId>org.springframework.data.examples</groupId>
+		<artifactId>spring-data-r2dbc-examples</artifactId>
+		<version>2.0.0.BUILD-SNAPSHOT</version>
+	</parent>
+
+	<artifactId>spring-data-r2dbc-example</artifactId>
+
+	<name>Spring Data R2DBC - Example</name>
+
+
+</project>

r2dbc/example/src/main/java/example/springdata/r2dbc/basics/Customer.java

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+/*
+ * Copyright 2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://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 example.springdata.r2dbc.basics;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.Value;
+
+import org.springframework.data.annotation.Id;
+
+/**
+ * @author Oliver Gierke
+ */
+@Data
+@AllArgsConstructor
+class Customer {
+	@Id Integer id;
+	String firstname, lastname;
+}

r2dbc/example/src/main/java/example/springdata/r2dbc/basics/CustomerRepository.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://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 example.springdata.r2dbc.basics;
+
+import reactor.core.publisher.Flux;
+
+import org.springframework.data.r2dbc.repository.query.Query;
+import org.springframework.data.repository.reactive.ReactiveCrudRepository;
+
+/**
+ * @author Oliver Gierke
+ */
+interface CustomerRepository extends ReactiveCrudRepository<Customer, Long> {
+
+	@Query("select id, firstname, lastname from customer c where c.lastname = $1")
+	Flux<Customer> findByLastnameLike(String lastname);
+}

r2dbc/example/src/test/java/example/springdata/r2dbc/basics/CustomerRepositoryIntegrationTests.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://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 example.springdata.r2dbc.basics;
+
+import reactor.core.publisher.Hooks;
+import reactor.test.StepVerifier;
+
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.data.r2dbc.function.DatabaseClient;
+import org.springframework.test.context.junit4.SpringRunner;
+
+/**
+ * @author Oliver Gierke
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(classes = InfrastructureConfiguration.class)
+public class CustomerRepositoryIntegrationTests {
+
+	@Autowired CustomerRepository customers;
+	@Autowired DatabaseClient database;
+
+	@Before
+	public void setUp() {
+
+		Hooks.onOperatorDebug();
+
+		List<String> statements = Arrays.asList(//
+				"DROP TABLE IF EXISTS customer;",
+				"CREATE TABLE customer ( id SERIAL PRIMARY KEY, firstname VARCHAR(100) NOT NULL, lastname VARCHAR(100) NOT NULL);");
+
+		statements.forEach(it -> database.execute() //
+				.sql(it) //
+				.fetch() //
+				.rowsUpdated() //
+				.as(StepVerifier::create) //
+				.verifyComplete());
+	}
+
+	@Test
+	public void executesFindAll() throws IOException {
+
+		Customer dave = new Customer(null, "Dave", "Matthews");
+		Customer carter = new Customer(null, "Carter", "Beauford");
+
+		insertCustomers(dave, carter);
+
+		customers.findAll() //
+				.as(StepVerifier::create) //
+				.assertNext(dave::equals) //
+				.assertNext(carter::equals) //
+				.verifyComplete();
+	}
+
+	@Test
+	public void executesAnnotatedQuery() throws IOException {
+
+		Customer dave = new Customer(null, "Dave", "Matthews");
+		Customer carter = new Customer(null, "Carter", "Beauford");
+
+		insertCustomers(dave, carter);
+
+		customers.findByLastnameLike("Matthews") //
+				.as(StepVerifier::create) //
+				.assertNext(dave::equals) //
+				.verifyComplete();
+	}
+
+	private void insertCustomers(Customer... customers) {
+
+		this.customers.saveAll(Arrays.asList(customers))//
+				.as(StepVerifier::create) //
+				.expectNextCount(2) //
+				.verifyComplete();
+	}
+}

r2dbc/example/src/test/java/example/springdata/r2dbc/basics/InfrastructureConfiguration.java

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+/*
+ * Copyright 2018 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://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 example.springdata.r2dbc.basics;
+
+import io.r2dbc.postgresql.PostgresqlConnectionConfiguration;
+import io.r2dbc.postgresql.PostgresqlConnectionFactory;
+import io.r2dbc.spi.ConnectionFactory;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.r2dbc.function.DatabaseClient;
+import org.springframework.data.r2dbc.repository.support.R2dbcRepositoryFactory;
+import org.springframework.data.relational.core.mapping.RelationalMappingContext;
+import org.testcontainers.containers.PostgreSQLContainer;
+
+import javax.annotation.PreDestroy;
+
+/**
+ * @author Oliver Gierke
+ */
+@Configuration
+class InfrastructureConfiguration {
+
+	private PostgreSQLContainer postgres = new PostgreSQLContainer();
+
+	@Bean
+	CustomerRepository customerRepository(R2dbcRepositoryFactory factory) {
+		return factory.getRepository(CustomerRepository.class);
+	}
+
+	@Bean
+	R2dbcRepositoryFactory repositoryFactory(DatabaseClient client) {
+
+		RelationalMappingContext context = new RelationalMappingContext();
+		context.afterPropertiesSet();
+
+		return new R2dbcRepositoryFactory(client, context);
+	}
+
+	@Bean
+	DatabaseClient databaseClient(ConnectionFactory factory) {
+
+		return DatabaseClient.builder() //
+				.connectionFactory(factory) //
+				.build();
+	}
+
+	@Bean
+	PostgresqlConnectionFactory connectionFactory() {
+
+
+		postgres.start();
+
+		PostgresqlConnectionConfiguration config = PostgresqlConnectionConfiguration.builder() //
+				.host(postgres.getContainerIpAddress()) //
+				.port(postgres.getFirstMappedPort()) //
+				.database(postgres.getDatabaseName()) //
+				.username(postgres.getUsername()) //
+				.password(postgres.getPassword()) //
+				.build();
+
+		return new PostgresqlConnectionFactory(config);
+	}
+
+	@PreDestroy
+	void shutdown() {
+		postgres.stop();
+	}
+}