DATAREDIS-643 - Provide ReactiveStringRedisTemplate.

Provide a String-focused convenience class for simpler bootstrapping and to provide a dedicated bean type for the application context when using auto-configuration.

Original Pull Request: #288

src/main/asciidoc/reference/reactive-redis.adoc

@@ -113,7 +113,7 @@ class RedisConfiguration {
 
   @Bean
   ReactiveRedisTemplate<String, String> reactiveRedisTemplate(ReactiveRedisConnectionFactory factory) {
-    return new ReactiveRedisTemplate<>(connectionFactory, RedisSerializationContext.string());
+    return new ReactiveRedisTemplate<>(factory, RedisSerializationContext.string());
   }
 }
 ----
@@ -131,6 +131,36 @@ public class Example {
 }
 ----
 
+[[redis:reactive:string]]
+== String-focused convenience classes
+
+Since it's quite common for keys and values stored in Redis to be a `java.lang.String`, the Redis module provides a String-based extension to `ReactiveRedisTemplate`: `ReactiveStringRedisTemplate` is a convenient one-stop solution for intensive `String` operations. In addition to being bound to `String` keys, the template uses the String-based `RedisSerializationContext` underneath which means the stored keys and values are human readable (assuming the same encoding is used both in Redis and your code). For example:
+
+[source,java]
+----
+@Configuration
+class RedisConfiguration {
+
+  @Bean
+  ReactiveStringRedisTemplate reactiveRedisTemplate(ReactiveRedisConnectionFactory factory) {
+    return new ReactiveStringRedisTemplate<>(factory);
+  }
+}
+----
+
+[source,java]
+----
+public class Example {
+
+  @Autowired
+  private ReactiveStringRedisTemplate redisTemplate;
+
+  public Mono<Long> addLink(String userId, URL url) {
+    return redisTemplate.opsForList().leftPush(userId, url.toExternalForm());
+  }
+}
+----
+
 == Reactive Scripting
 
 Executing Redis scripts via the reactive infrastructure can be done using the `ReactiveScriptExecutor` accessed best via `ReactiveRedisTemplate`.

src/main/java/org/springframework/data/redis/core/ReactiveStringRedisTemplate.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2017 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 org.springframework.data.redis.core;
+
+import org.springframework.data.redis.connection.ReactiveRedisConnectionFactory;
+import org.springframework.data.redis.serializer.RedisSerializationContext;
+
+/**
+ * String-focused extension of {@link ReactiveRedisTemplate}. Since most operations against Redis are {@link String}
+ * based, this class provides a dedicated arrangement that minimizes configuration of its more generic
+ * {@link ReactiveRedisTemplate template} especially in terms of serializers.
+ * 
+ * @author Mark Paluch
+ * @since 2.1
+ */
+public class ReactiveStringRedisTemplate extends ReactiveRedisTemplate<String, String> {
+
+	/**
+	 * Creates new {@link ReactiveRedisTemplate} using given {@link ReactiveRedisConnectionFactory} applying default
+	 * {@link String} serialization.
+	 *
+	 * @param connectionFactory must not be {@literal null}.
+	 * @see RedisSerializationContext#string()
+	 */
+	public ReactiveStringRedisTemplate(ReactiveRedisConnectionFactory connectionFactory) {
+		this(connectionFactory, RedisSerializationContext.string());
+	}
+
+	/**
+	 * Creates new {@link ReactiveRedisTemplate} using given {@link ReactiveRedisConnectionFactory} and
+	 * {@link RedisSerializationContext}.
+	 *
+	 * @param connectionFactory must not be {@literal null}.
+	 * @param serializationContext must not be {@literal null}.
+	 */
+	public ReactiveStringRedisTemplate(ReactiveRedisConnectionFactory connectionFactory,
+			RedisSerializationContext<String, String> serializationContext) {
+		super(connectionFactory, serializationContext);
+	}
+
+	/**
+	 * Creates new {@link ReactiveRedisTemplate} using given {@link ReactiveRedisConnectionFactory} and
+	 * {@link RedisSerializationContext}.
+	 *
+	 * @param connectionFactory must not be {@literal null}.
+	 * @param serializationContext must not be {@literal null}.
+	 * @param exposeConnection flag indicating to expose the connection used.
+	 */
+	public ReactiveStringRedisTemplate(ReactiveRedisConnectionFactory connectionFactory,
+			RedisSerializationContext<String, String> serializationContext, boolean exposeConnection) {
+		super(connectionFactory, serializationContext, exposeConnection);
+	}
+}

src/test/java/org/springframework/data/redis/core/ReactiveStringRedisTemplateIntegrationTests.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2017 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 org.springframework.data.redis.core;
+
+import reactor.test.StepVerifier;
+
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.springframework.data.redis.ConnectionFactoryTracker;
+import org.springframework.data.redis.SettingsUtils;
+import org.springframework.data.redis.connection.ReactiveRedisConnectionFactory;
+import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
+import org.springframework.data.redis.connection.lettuce.LettuceTestClientConfiguration;
+
+/**
+ * Integration tests for {@link ReactiveStringRedisTemplate}.
+ * 
+ * @author Mark Paluch
+ */
+public class ReactiveStringRedisTemplateIntegrationTests {
+
+	private static ReactiveRedisConnectionFactory connectionFactory;
+
+	private ReactiveStringRedisTemplate template;
+
+	@BeforeClass
+	public static void beforeClass() {
+
+		LettuceConnectionFactory connectionFactory = new LettuceConnectionFactory(SettingsUtils.standaloneConfiguration(),
+				LettuceTestClientConfiguration.create());
+		connectionFactory.afterPropertiesSet();
+		ConnectionFactoryTracker.add(connectionFactory);
+
+		ReactiveStringRedisTemplateIntegrationTests.connectionFactory = connectionFactory;
+	}
+
+	@Before
+	public void before() {
+
+		template = new ReactiveStringRedisTemplate(connectionFactory);
+
+		StepVerifier.create(template.execute(connection -> connection.serverCommands().flushDb())).expectNext("OK")
+				.verifyComplete();
+	}
+
+	@Test // DATAREDIS-643
+	public void shouldSetAndGetKeys() {
+
+		StepVerifier.create(template.opsForValue().set("key", "value")).expectNext(true).verifyComplete();
+		StepVerifier.create(template.opsForValue().get("key")).expectNext("value").verifyComplete();
+	}
+}