Adds support for Redis SET … GET command.

Closes #2853
Original pull request: #3017

Author: marcingrzejszczak

src/main/java/org/springframework/data/redis/connection/DefaultStringRedisConnection.java

@@ -770,6 +770,11 @@ public Boolean set(byte[] key, byte[] value, Expiration expiration, SetOption op
 		return convertAndReturn(delegate.set(key, value, expiration, option), Converters.identityConverter());
 	}
 
+	@Override
+	public byte[] setGet(byte[] key, byte[] value, Expiration expiration, SetOption option) {
+		return convertAndReturn(delegate.setGet(key, value, expiration, option), Converters.identityConverter());
+	}
+
 	@Override
 	public Boolean setBit(byte[] key, long offset, boolean value) {
 		return convertAndReturn(delegate.setBit(key, offset, value), Converters.identityConverter());

src/main/java/org/springframework/data/redis/connection/DefaultedRedisConnection.java

@@ -326,6 +326,13 @@ default Boolean set(byte[] key, byte[] value, Expiration expiration, SetOption o
 		return stringCommands().set(key, value, expiration, option);
 	}
 
+	/** @deprecated in favor of {@link RedisConnection#stringCommands()}}. */
+	@Override
+	@Deprecated
+	default byte[] setGet(byte[] key, byte[] value, Expiration expiration, SetOption option) {
+		return stringCommands().setGet(key, value, expiration, option);
+	}
+
 	/** @deprecated in favor of {@link RedisConnection#stringCommands()}}. */
 	@Override
 	@Deprecated

src/main/java/org/springframework/data/redis/connection/ReactiveStringCommands.java

@@ -47,6 +47,7 @@
  *
  * @author Christoph Strobl
  * @author Mark Paluch
+ * @author Marcin Grzejszczak
  * @since 2.0
  */
 public interface ReactiveStringCommands {
@@ -193,6 +194,41 @@ default Mono<Boolean> set(ByteBuffer key, ByteBuffer value, Expiration expiratio
 	 */
 	Flux<BooleanResponse<SetCommand>> set(Publisher<SetCommand> commands);
 
+	/**
+	 * Set {@literal value} for {@literal key} with {@literal expiration} and {@literal options}. Return the old
+	 * string stored at key, or nil if key did not exist. An error is returned and SET aborted if the value
+	 * stored at key is not a string.
+	 *
+	 * @param key must not be {@literal null}.
+	 * @param value must not be {@literal null}.
+	 * @param expiration must not be {@literal null}. Use {@link Expiration#persistent()} for no expiration time or
+	 *          {@link Expiration#keepTtl()} to keep the existing.
+	 * @param option must not be {@literal null}.
+	 * @return
+	 * @see <a href="https://redis.io/commands/set">Redis Documentation: SET</a>
+	 * @since 3.4
+	 */
+	@Nullable
+	default Mono<ByteBuffer> setGet(ByteBuffer key, ByteBuffer value, Expiration expiration, SetOption option) {
+
+		Assert.notNull(key, "Key must not be null");
+		Assert.notNull(value, "Value must not be null");
+
+		return setGet(Mono.just(SetCommand.set(key).value(value).withSetOption(option).expiring(expiration))).next()
+				.map(CommandResponse::getOutput);
+	}
+
+	/**
+	 * Set each and every item separately by invoking {@link SetCommand}. Return the old
+	 * string stored at key, or nil if key did not exist. An error is returned and SET aborted if the value
+	 * stored at key is not a string.
+	 *
+	 * @param commands must not be {@literal null}.
+	 * @return {@link Flux} of {@link ByteBufferResponse} holding the {@link SetCommand} along with the command result.
+	 * @see <a href="https://redis.io/commands/set">Redis Documentation: SET</a>
+	 */
+	Flux<ByteBufferResponse<SetCommand>> setGet(Publisher<SetCommand> commands);
+
 	/**
 	 * Get single element stored at {@literal key}.
 	 *

src/main/java/org/springframework/data/redis/connection/RedisStringCommands.java

@@ -122,6 +122,22 @@ enum BitOperation {
 	@Nullable
 	Boolean set(byte[] key, byte[] value, Expiration expiration, SetOption option);
 
+	/**
+	 * Set {@code value} for {@code key}. Return the old string stored at key, or nil if key did not exist.
+	 * An error is returned and SET aborted if the value stored at key is not a string.
+	 *
+	 * @param key must not be {@literal null}.
+	 * @param value must not be {@literal null}.
+	 * @param expiration must not be {@literal null}. Use {@link Expiration#persistent()} to not set any ttl or
+	 *          {@link Expiration#keepTtl()} to keep the existing expiration.
+	 * @param option must not be {@literal null}. Use {@link SetOption#upsert()} to add non existing.
+	 * @return {@literal null} when used in pipeline / transaction.
+	 * @since 3.4
+	 * @see <a href="https://redis.io/commands/set">Redis Documentation: SET</a>
+	 */
+	@Nullable
+	byte[] setGet(byte[] key, byte[] value, Expiration expiration, SetOption option);
+
 	/**
 	 * Set {@code value} for {@code key}, only if {@code key} does not exist.
 	 *

src/main/java/org/springframework/data/redis/connection/jedis/JedisClusterStringCommands.java

@@ -150,6 +150,24 @@ public Boolean set(byte[] key, byte[] value, Expiration expiration, SetOption op
 		}
 	}
 
+	@Override
+	public byte[] setGet(byte[] key, byte[] value, Expiration expiration, SetOption option) {
+
+		Assert.notNull(key, "Key must not be null");
+		Assert.notNull(value, "Value must not be null");
+		Assert.notNull(expiration, "Expiration must not be null");
+		Assert.notNull(option, "Option must not be null");
+
+		SetParams setParams = JedisConverters.toSetCommandExPxArgument(expiration,
+				JedisConverters.toSetCommandNxXxArgument(option));
+
+		try {
+			return connection.getCluster().setGet(key, value, setParams);
+		} catch (Exception ex) {
+			throw convertJedisAccessException(ex);
+		}
+	}
+
 	@Override
 	public Boolean setNX(byte[] key, byte[] value) {
 

src/main/java/org/springframework/data/redis/connection/jedis/JedisStringCommands.java

@@ -116,6 +116,20 @@ public Boolean set(byte[] key, byte[] value, Expiration expiration, SetOption op
 				.getOrElse(Converters.stringToBooleanConverter(), () -> false);
 	}
 
+	@Override
+	@Nullable
+	public byte[] setGet(byte[] key, byte[] value, Expiration expiration, SetOption option) {
+		Assert.notNull(key, "Key must not be null");
+		Assert.notNull(value, "Value must not be null");
+		Assert.notNull(expiration, "Expiration must not be null");
+		Assert.notNull(option, "Option must not be null");
+
+		SetParams params = JedisConverters.toSetCommandExPxArgument(expiration,
+				JedisConverters.toSetCommandNxXxArgument(option));
+
+		return connection.invoke().just(Jedis::setGet, PipelineBinaryCommands::setGet, key, value, params);
+	}
+
 	@Override
 	public Boolean setNX(byte[] key, byte[] value) {
 

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceReactiveStringCommands.java

@@ -105,6 +105,19 @@ public Flux<BooleanResponse<SetCommand>> set(Publisher<SetCommand> commands) {
 		}));
 	}
 
+	@Override
+	public Flux<ByteBufferResponse<SetCommand>> setGet(Publisher<SetCommand> commands) {
+		return this.connection.execute(reactiveCommands -> Flux.from(commands).concatMap((command) -> {
+
+			Assert.notNull(command.getKey(), "Key must not be null");
+			Assert.notNull(command.getValue(), "Value must not be null");
+
+			return reactiveCommands.setGet(command.getKey(), command.getValue())
+					.map(v -> new ByteBufferResponse<>(command, v))
+					.defaultIfEmpty(new AbsentByteBufferResponse<>(command));
+		}));
+	}
+
 	@Override
 	public Flux<ByteBufferResponse<SetCommand>> getSet(Publisher<SetCommand> commands) {
 

src/main/java/org/springframework/data/redis/connection/lettuce/LettuceStringCommands.java

@@ -115,6 +115,18 @@ public Boolean set(byte[] key, byte[] value, Expiration expiration, SetOption op
 				.orElse(LettuceConverters.stringToBooleanConverter(), false);
 	}
 
+	@Override
+	@Nullable
+	public byte[] setGet(byte[] key, byte[] value, Expiration expiration, SetOption option) {
+		Assert.notNull(key, "Key must not be null");
+		Assert.notNull(value, "Value must not be null");
+		Assert.notNull(expiration, "Expiration must not be null");
+		Assert.notNull(option, "Option must not be null");
+
+		return connection.invoke()
+				.just(RedisStringAsyncCommands::setGet, key, value, LettuceConverters.toSetArgs(expiration, option));
+	}
+
 	@Override
 	public Boolean setNX(byte[] key, byte[] value) {
 

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

@@ -49,6 +49,19 @@ public interface BoundValueOperations<K, V> extends BoundKeyOperations<K> {
 	 */
 	void set(V value, long timeout, TimeUnit unit);
 
+	/**
+	 * Set the {@code value} and expiration {@code timeout} for the bound key. Return the old
+	 * string stored at key, or nil if key did not exist. An error is returned and SET aborted if the value
+	 * stored at key is not a string.
+	 *
+	 * @param value must not be {@literal null}.
+	 * @param timeout
+	 * @param unit must not be {@literal null}.
+	 * @see <a href="https://redis.io/commands/set">Redis Documentation: SET</a>
+	 * @since 3.4
+	 */
+	V setGet(V value, long timeout, TimeUnit unit);
+
 	/**
 	 * Set the {@code value} and expiration {@code timeout} for the bound key.
 	 *

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

@@ -77,6 +77,18 @@ public Mono<Boolean> set(K key, V value, Duration timeout) {
 				stringCommands.set(rawKey(key), rawValue(value), Expiration.from(timeout), SetOption.UPSERT));
 	}
 
+	@Override
+	public Mono<V> setGet(K key, V value, Duration timeout) {
+
+		Assert.notNull(key, "Key must not be null");
+		Assert.notNull(value, "Value must not be null");
+		Assert.notNull(timeout, "Duration must not be null");
+
+		return createMono(stringCommands ->
+				stringCommands.setGet(rawKey(key), rawValue(value), Expiration.from(timeout), SetOption.UPSERT))
+				.map(this::readRequiredValue);
+	}
+
 	@Override
 	public Mono<Boolean> setIfAbsent(K key, V value) {