DATAREDIS-693 - Add support for UNLINK.

We now support UNLINK for both Jedis & Lettuce throughout the single node and cluster connection. Reactive support is only available for Lettuce.

Original pull request: #294.

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

@@ -252,6 +252,15 @@ public class DefaultStringRedisConnection implements StringRedisConnection, Deco
 		return convertAndReturn(delegate.del(keys), identityConverter);
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.connection.RedisKeyCommands#unlink(byte[][])
+	 */
+	@Override
+	public Long unlink(byte[]... keys) {
+		return convertAndReturn(delegate.unlink(keys), identityConverter);
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.redis.connection.RedisTxCommands#discard()
@@ -1785,6 +1794,15 @@ public class DefaultStringRedisConnection implements StringRedisConnection, Deco
 		return del(serializeMulti(keys));
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.connection.StringRedisConnection#unlink(java.lang.String[])
+	 */
+	@Override
+	public Long unlink(String... keys) {
+		return unlink(serializeMulti(keys));
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.redis.connection.StringRedisConnection#echo(java.lang.String)

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

@@ -68,6 +68,13 @@ public interface DefaultedRedisConnection extends RedisConnection {
 		return keyCommands().del(keys);
 	}
 
+	/** @deprecated in favor of {@link RedisConnection#keyCommands()}. */
+	@Override
+	@Deprecated
+	default Long unlink(byte[]... keys) {
+		return keyCommands().unlink(keys);
+	}
+
 	/** @deprecated in favor of {@link RedisConnection#keyCommands()}. */
 	@Override
 	@Deprecated

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

@@ -264,6 +264,31 @@ public interface ReactiveKeyCommands {
 	 */
 	Flux<NumericResponse<KeyCommand, Long>> del(Publisher<KeyCommand> keys);
 
+	/**
+	 * Unlink {@literal key}.
+	 *
+	 * @param keys must not be {@literal null}.
+	 * @return
+	 * @see <a href="http://redis.io/commands/unlink">Redis Documentation: UNLINK</a>
+	 * @since 2.1
+	 */
+	default Mono<Long> unlink(List<ByteBuffer> keys) {
+
+		Assert.notNull(keys, "Key must not be null!");
+
+		return unlink(Mono.just(keys)).next().map(NumericResponse::getOutput);
+	}
+
+	/**
+	 * Unlink {@literal keys}.
+	 *
+	 * @param keys must not be {@literal null}.
+	 * @return {@link Flux} of {@link NumericResponse} holding the {@literal key} removed along with the deletion result.
+	 * @see <a href="http://redis.io/commands/unlink">Redis Documentation: UNLINK</a>
+	 * @since 2.1
+	 */
+	Flux<NumericResponse<List<ByteBuffer>, Long>> unlink(Publisher<List<ByteBuffer>> keys);
+
 	/**
 	 * Delete multiple {@literal keys} one in one batch.
 	 *

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

@@ -70,6 +70,18 @@ public interface RedisKeyCommands {
 	@Nullable
 	Long del(byte[]... keys);
 
+	/**
+	 * Unlinks the {@code keys} from the keyspace. Unlike with {@link #del(byte[]...)} the actual removal here happens
+	 * asynchronously.
+	 *
+	 * @param keys must not be {@literal null}.
+	 * @return {@literal null} when used in pipeline / transaction.
+	 * @see <a href="http://redis.io/commands/unlink">Redis Documentation: UNLINK</a>
+	 * @since 2.1
+	 */
+	@Nullable
+	Long unlink(byte[]... keys);
+
 	/**
 	 * Determine the type stored at {@code key}.
 	 *

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

@@ -113,6 +113,18 @@ public interface StringRedisConnection extends RedisConnection {
 	 */
 	Long del(String... keys);
 
+	/**
+	 * Unlinks the {@code keys} from the keyspace. Unlike with {@link #del(byte[]...)} the actual removal here happens
+	 * asynchronously.
+	 *
+	 * @param keys must not be {@literal null}.
+	 * @return {@literal null} when used in pipeline / transaction.
+	 * @see <a href="http://redis.io/commands/unlink">Redis Documentation: UNLINK</a>
+	 * @since 2.1
+	 */
+	@Nullable
+	Long unlink(String... keys);
+
 	/**
 	 * Determine the type stored at {@code key}.
 	 *

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

@@ -81,6 +81,20 @@ class JedisClusterKeyCommands implements RedisKeyCommands {
 				.resultsAsList().size();
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.connection.RedisKeyCommands#unlink(byte[][])
+	 */
+	@Nullable
+	@Override
+	public Long unlink(byte[]... keys) {
+
+		Assert.notNull(keys, "Keys must not be null!");
+
+		return connection.<Long> execute("UNLINK", Arrays.asList(keys), Collections.emptyList()).stream()
+				.mapToLong(val -> val).sum();
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.redis.connection.RedisKeyCommands#type(byte[])

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

@@ -120,6 +120,19 @@ class JedisKeyCommands implements RedisKeyCommands {
 		}
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.connection.RedisKeyCommands#unlink(byte[][])
+	 */
+	@Nullable
+	@Override
+	public Long unlink(byte[]... keys) {
+
+		Assert.notNull(keys, "Keys must not be null!");
+
+		return Long.class.cast(connection.execute("UNLINK", keys));
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.redis.connection.RedisKeyCommands#type(byte[])

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

@@ -126,6 +126,30 @@ class LettuceKeyCommands implements RedisKeyCommands {
 		}
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.connection.RedisKeyCommands#unlink(byte[][])
+	 */
+	@Override
+	public Long unlink(byte[]... keys) {
+
+		Assert.notNull(keys, "Keys must not be null!");
+
+		try {
+			if (isPipelined()) {
+				pipeline(connection.newLettuceResult(getAsyncConnection().unlink(keys)));
+				return null;
+			}
+			if (isQueueing()) {
+				transaction(connection.newLettuceResult(getAsyncConnection().unlink(keys)));
+				return null;
+			}
+			return getConnection().unlink(keys);
+		} catch (Exception ex) {
+			throw convertLettuceAccessException(ex);
+		}
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.redis.connection.RedisKeyCommands#type(byte[])

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

@@ -175,6 +175,22 @@ class LettuceReactiveKeyCommands implements ReactiveKeyCommands {
 		}));
 	}
 
+	/*
+	 * (non-Javadoc)
+	 * @see org.springframework.data.redis.connection.ReactiveRedisConnection.ReactiveKeyCommands#unlink(org.reactivestreams.Publisher)
+	 */
+	@Override
+	public Flux<NumericResponse<List<ByteBuffer>, Long>> unlink(Publisher<List<ByteBuffer>> keysCollection) {
+
+		return connection.execute(cmd -> Flux.from(keysCollection).flatMap((keys) -> {
+
+			Assert.notEmpty(keys, "Keys must not be null!");
+
+			return cmd.unlink(keys.stream().collect(Collectors.toList()).toArray(new ByteBuffer[keys.size()]))
+					.map((value) -> new NumericResponse<>(keys, value));
+		}));
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.redis.connection.ReactiveRedisConnection.ReactiveKeyCommands#mDel(org.reactivestreams.Publisher)