DATAREDIS-784 - Add support for reactive increment and decrement commands to ReactiveValueOperations.

We now support reactive execution of the following increment and decrement commands through ReactiveValueOperations:

- INCR
- INCRBY
- INCRBYFLOAT
- DECR
- DECRBY

Original pull request: #322.

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

@@ -273,6 +273,61 @@ class DefaultReactiveValueOperations<K, V> implements ReactiveValueOperations<K,
 
 		return template.createMono(connection -> connection.keyCommands().del(rawKey(key))).map(l -> l != 0);
 	}
+	
+	/* (non-Javadoc)
+	 * @see org.springframework.data.redis.core.ReactiveValueOperations#increment(java.lang.Object)
+	 */
+	@Override
+	public Mono<Long> increment(K key) {
+
+		Assert.notNull(key, "Key must not be null!");
+
+		return incrementBy(key, 1L);
+	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.redis.core.ReactiveValueOperations#incrementBy(java.lang.Object, long)
+	 */
+	@Override
+	public Mono<Long> incrementBy(K key, long delta) {
+
+		Assert.notNull(key, "Key must not be null!");
+
+		return template.createMono(connection -> connection.numberCommands().incrBy(rawKey(key), delta));
+	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.redis.core.ReactiveValueOperations#incrementBy(java.lang.Object, double)
+	 */
+	@Override
+	public Mono<Double> incrementBy(K key, double delta) {
+
+		Assert.notNull(key, "Key must not be null!");
+
+		return template.createMono(connection -> connection.numberCommands().incrBy(rawKey(key), delta));
+	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.redis.core.ReactiveValueOperations#decrement(java.lang.Object)
+	 */
+	@Override
+	public Mono<Long> decrement(K key) {
+
+		Assert.notNull(key, "Key must not be null!");
+
+		return incrementBy(key, -1L);
+	}
+
+	/* (non-Javadoc)
+	 * @see org.springframework.data.redis.core.ReactiveValueOperations#decrementBy(java.lang.Object, long)
+	 */
+	@Override
+	public Mono<Long> decrementBy(K key, long delta) {
+
+		Assert.notNull(key, "Key must not be null!");
+
+		return incrementBy(key, -delta);
+	}
 
 	private <T> Mono<T> createMono(Function<ReactiveStringCommands, Publisher<T>> function) {
 

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

@@ -193,4 +193,44 @@ public interface ReactiveValueOperations<K, V> {
 	 * @param key must not be {@literal null}.
 	 */
 	Mono<Boolean> delete(K key);
+	
+	/**
+	 * Increments the number stored at {@code key} by one.
+	 *
+	 * @param key must not be {@literal null}.
+	 * @see <a href="http://redis.io/commands/incr">Redis Documentation: INCR</a>
+	 */
+	Mono<Long> increment(K key);
+
+	/**
+	 * Increments the number stored at {@code key} by {@code delta}.
+	 * @param key must not be {@literal null}.
+	 * @param delta
+	 * @see <a href="http://redis.io/commands/incrby">Redis Documentation: INCRBY</a>
+	 */
+	Mono<Long> incrementBy(K key, long delta);
+
+	/**
+	 * Increment the string representing a floating point number stored at {@code key} by {@code delta}.
+	 * @param key must not be {@literal null}.
+	 * @param delta
+	 * @see <a href="http://redis.io/commands/incrbyfloat">Redis Documentation: INCRBYFLOAT</a>
+	 */
+	Mono<Double> incrementBy(K key, double delta);
+
+	/**
+	 * Decrements the number stored at {@code key} by one.
+	 *
+	 * @param key must not be {@literal null}.
+	 * @see <a href="http://redis.io/commands/decr">Redis Documentation: DECR</a>
+	 */
+	Mono<Long> decrement(K key);
+
+	/**
+	 * Decrements the number stored at {@code key} by {@code delta}.
+	 * @param key must not be {@literal null}.
+	 * @param delta
+	 * @see <a href="http://redis.io/commands/decrby">Redis Documentation: DECRBY</a>
+	 */
+	Mono<Long> decrementBy(K key, long delta);
 }