Add support for R2DBC

This commit introduces support for R2DBC ("Reactive Relational Database
Connectivity") with custom ConnectionFactory implementations, a
functional DatabaseClient for SQL execution, transaction management, a
bind marker abstraction database initialization utilities, and
exception translation.

Closes gh-25065

Author: mp911de

build.gradle

@@ -26,6 +26,7 @@ configure(allprojects) { project ->
 			mavenBom "com.fasterxml.jackson:jackson-bom:2.11.0"
 			mavenBom "io.netty:netty-bom:4.1.50.Final"
 			mavenBom "io.projectreactor:reactor-bom:2020.0.0-SNAPSHOT"
+			mavenBom "io.r2dbc:r2dbc-bom:Arabba-SR5"
 			mavenBom "io.rsocket:rsocket-bom:1.0.1"
 			mavenBom "org.eclipse.jetty:jetty-bom:9.4.30.v20200611"
 			mavenBom "org.jetbrains.kotlin:kotlin-bom:1.4-M2"

settings.gradle

@@ -24,6 +24,7 @@ include "spring-expression"
 include "spring-instrument"
 include "spring-jcl"
 include "spring-jdbc"
+include "spring-r2dbc"
 include "spring-jms"
 include "spring-messaging"
 include "spring-orm"

spring-r2dbc/spring-r2dbc.gradle

@@ -0,0 +1,29 @@
+description = "Spring R2DBC"
+
+apply plugin: "kotlin"
+
+// Workaround for https://youtrack.jetbrains.com/issue/KT-39610
+configurations["optional"].attributes.attribute(
+	org.gradle.api.attributes.Usage.USAGE_ATTRIBUTE,
+	objects.named(Usage.class, "java-runtime")
+)
+
+dependencies {
+	compile(project(":spring-beans"))
+	compile(project(":spring-core"))
+	compile(project(":spring-tx"))
+	compile("io.r2dbc:r2dbc-spi")
+	compile("io.projectreactor:reactor-core")
+	compileOnly(project(":kotlin-coroutines"))
+	optional("org.jetbrains.kotlin:kotlin-reflect")
+	optional("org.jetbrains.kotlin:kotlin-stdlib")
+	optional("org.jetbrains.kotlinx:kotlinx-coroutines-core")
+	optional("org.jetbrains.kotlinx:kotlinx-coroutines-reactor")
+	testCompile(project(":kotlin-coroutines"))
+	testCompile(testFixtures(project(":spring-beans")))
+	testCompile(testFixtures(project(":spring-core")))
+	testCompile(testFixtures(project(":spring-context")))
+	testCompile("io.projectreactor:reactor-test")
+	testCompile("io.r2dbc:r2dbc-h2")
+	testCompile("io.r2dbc:r2dbc-spi-test:0.8.1.RELEASE")
+}

spring-r2dbc/src/main/java/org/springframework/r2dbc/BadSqlGrammarException.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2002-2020 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
+ *
+ *      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.springframework.r2dbc;
+
+import io.r2dbc.spi.R2dbcException;
+
+import org.springframework.dao.InvalidDataAccessResourceUsageException;
+
+
+/**
+ * Exception thrown when SQL specified is invalid. Such exceptions always have a
+ * {@link io.r2dbc.spi.R2dbcException} root cause.
+ *
+ * <p>It would be possible to have subclasses for no such table, no such column etc.
+ * A custom R2dbcExceptionTranslator could create such more specific exceptions,
+ * without affecting code using this class.
+ *
+ * @author Mark Paluch
+ * @since 5.3
+ */
+@SuppressWarnings("serial")
+public class BadSqlGrammarException extends InvalidDataAccessResourceUsageException {
+
+	private final String sql;
+
+
+	/**
+	 * Constructor for BadSqlGrammarException.
+	 * @param task name of current task
+	 * @param sql the offending SQL statement
+	 * @param ex the root cause
+	 */
+	public BadSqlGrammarException(String task, String sql, R2dbcException ex) {
+		super(task + "; bad SQL grammar [" + sql + "]", ex);
+		this.sql = sql;
+	}
+
+
+	/**
+	 * Return the wrapped {@link R2dbcException}.
+	 */
+	public R2dbcException getR2dbcException() {
+		return (R2dbcException) getCause();
+	}
+
+	/**
+	 * Return the SQL that caused the problem.
+	 */
+	public String getSql() {
+		return this.sql;
+	}
+
+}

spring-r2dbc/src/main/java/org/springframework/r2dbc/UncategorizedR2dbcException.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2002-2020 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
+ *
+ *      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.springframework.r2dbc;
+
+import io.r2dbc.spi.R2dbcException;
+
+import org.springframework.dao.UncategorizedDataAccessException;
+import org.springframework.lang.Nullable;
+
+/**
+ * Exception thrown when we can't classify a {@link R2dbcException} into
+ * one of our generic data access exceptions.
+ *
+ * @author Mark Paluch
+ * @since 5.3
+ */
+@SuppressWarnings("serial")
+public class UncategorizedR2dbcException extends UncategorizedDataAccessException {
+
+	/** SQL that led to the problem. */
+	@Nullable
+	private final String sql;
+
+
+	/**
+	 * Constructor for {@code UncategorizedSQLException}.
+	 * @param msg the detail message
+	 * @param sql the offending SQL statement
+	 * @param ex the exception thrown by underlying data access API
+	 */
+	public UncategorizedR2dbcException(String msg, @Nullable String sql, R2dbcException ex) {
+		super(msg, ex);
+		this.sql = sql;
+	}
+
+
+	/**
+	 * Return the wrapped {@link R2dbcException}.
+	 */
+	public R2dbcException getR2dbcException() {
+		return (R2dbcException) getCause();
+	}
+
+	/**
+	 * Return the SQL that led to the problem (if known).
+	 */
+	@Nullable
+	public String getSql() {
+		return this.sql;
+	}
+
+}