Adds support to lPop or rPop N elements from a Redis List in ReactiveListOperations.

Closes spring-projects#2692

Author: jxblum

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

@@ -39,6 +39,7 @@
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author John Blum
  * @since 2.0
  */
 class DefaultReactiveListOperations<K, V> implements ReactiveListOperations<K, V> {
@@ -244,13 +245,21 @@ public Mono<V> leftPop(K key, Duration timeout) {
 
 		Assert.notNull(key, "Key must not be null");
 		Assert.notNull(timeout, "Duration must not be null");
-		Assert.isTrue(isZeroOrGreater1Second(timeout), "Duration must be either zero or greater or equal to 1 second");
+		Assert.isTrue(isZeroOrGreaterOneSecond(timeout), "Duration must be either zero or greater or equal to 1 second");
 
 		return createMono(listCommands ->
 				listCommands.blPop(Collections.singletonList(rawKey(key)), timeout)
 						.map(popResult -> readValue(popResult.getValue())));
 	}
 
+	@Override
+	public Flux<V> leftPop(K key, long count) {
+
+		Assert.notNull(key, "Key must not be null");
+
+		return createFlux(listCommands -> listCommands.lPop(rawKey(key), count).map(this::readValue));
+	}
+
 	@Override
 	public Mono<V> rightPop(K key) {
 
@@ -264,13 +273,21 @@ public Mono<V> rightPop(K key, Duration timeout) {
 
 		Assert.notNull(key, "Key must not be null");
 		Assert.notNull(timeout, "Duration must not be null");
-		Assert.isTrue(isZeroOrGreater1Second(timeout), "Duration must be either zero or greater or equal to 1 second");
+		Assert.isTrue(isZeroOrGreaterOneSecond(timeout), "Duration must be either zero or greater or equal to 1 second");
 
 		return createMono(listCommands ->
 				listCommands.brPop(Collections.singletonList(rawKey(key)), timeout)
 						.map(popResult -> readValue(popResult.getValue())));
 	}
 
+	@Override
+	public Flux<V> rightPop(K key, long count) {
+
+		Assert.notNull(key, "Key must not be null");
+
+		return createFlux(listCommands -> listCommands.rPop(rawKey(key), count).map(this::readValue));
+	}
+
 	@Override
 	public Mono<V> rightPopAndLeftPush(K sourceKey, K destinationKey) {
 
@@ -287,7 +304,7 @@ public Mono<V> rightPopAndLeftPush(K sourceKey, K destinationKey, Duration timeo
 		Assert.notNull(sourceKey, "Source key must not be null");
 		Assert.notNull(destinationKey, "Destination key must not be null");
 		Assert.notNull(timeout, "Duration must not be null");
-		Assert.isTrue(isZeroOrGreater1Second(timeout), "Duration must be either zero or greater or equal to 1 second");
+		Assert.isTrue(isZeroOrGreaterOneSecond(timeout), "Duration must be either zero or greater or equal to 1 second");
 
 		return createMono(listCommands ->
 				listCommands.bRPopLPush(rawKey(sourceKey), rawKey(destinationKey), timeout).map(this::readValue));
@@ -315,7 +332,7 @@ private <T> Flux<T> createFlux(Function<ReactiveListCommands, Publisher<T>> func
 		return template.doCreateFlux(connection -> function.apply(connection.listCommands()));
 	}
 
-	private boolean isZeroOrGreater1Second(Duration timeout) {
+	private boolean isZeroOrGreaterOneSecond(Duration timeout) {
 		return timeout.isZero() || timeout.getNano() % TimeUnit.NANOSECONDS.convert(1, TimeUnit.SECONDS) == 0;
 	}
 

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

@@ -32,6 +32,7 @@
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author John Blum
  * @see <a href="https://redis.io/commands#list">Redis Documentation: List Commands</a>
  * @since 2.0
  */
@@ -325,6 +326,16 @@ default Mono<V> move(MoveFrom<K> from, MoveTo<K> to, Duration timeout) {
 	 */
 	Mono<V> leftPop(K key, Duration timeout);
 
+	/**
+	 * Removes {@link Long count} elements from the left-side of the Redis list stored at key.
+	 *
+	 * @param key {@link K Key} referring to the list stored in Redis; must not be {@literal null}.
+	 * @param count {@link Long count} of the number of elements to remove from the left-side of the Redis list.
+	 * @return a {@link Flux} containing the elements removed from the Redis list.
+	 * @since 3.2
+	 */
+	Flux<V> leftPop(K key, long count);
+
 	/**
 	 * Removes and returns last element in list stored at {@code key}.
 	 *
@@ -347,6 +358,16 @@ default Mono<V> move(MoveFrom<K> from, MoveTo<K> to, Duration timeout) {
 	 */
 	Mono<V> rightPop(K key, Duration timeout);
 
+	/**
+	 * Removes {@link Long count} elements from the right-side of the Redis list stored at key.
+	 *
+	 * @param key {@link K Key} referring to the list stored in Redis; must not be {@literal null}.
+	 * @param count {@link Long count} of the number of elements to remove from the right-side of the Redis list.
+	 * @return a {@link Flux} containing the elements removed from the Redis list.
+	 * @since 3.2
+	 */
+	Flux<V> rightPop(K key, long count);
+
 	/**
 	 * Remove the last element from list at {@code sourceKey}, append it to {@code destinationKey} and return its value.
 	 *

src/main/kotlin/org/springframework/data/redis/core/ReactiveListOperationsExtensions.kt

@@ -183,6 +183,15 @@ suspend fun <K : Any, V : Any> ReactiveListOperations<K, V>.leftPopAndAwait(key:
 suspend fun <K : Any, V : Any> ReactiveListOperations<K, V>.leftPopAndAwait(key: K, timeout: Duration): V? =
 		leftPop(key, timeout).awaitFirstOrNull()
 
+/**
+ * Coroutines variant of [ReactiveListOperations.leftPop] with count.
+ *
+ * @author John Blum
+ * @since 3.2
+ */
+fun <K : Any, V : Any> ReactiveListOperations<K, V>.leftPopAsFlow(key: K, count :Long): Flow<V> =
+		leftPop(key, count).asFlow()
+
 /**
  * Coroutines variant of [ReactiveListOperations.rightPop].
  *
@@ -201,6 +210,15 @@ suspend fun <K : Any, V : Any> ReactiveListOperations<K, V>.rightPopAndAwait(key
 suspend fun <K : Any, V : Any> ReactiveListOperations<K, V>.rightPopAndAwait(key: K, timeout: Duration): V? =
 		rightPop(key, timeout).awaitFirstOrNull()
 
+/**
+ * Coroutines variant of [ReactiveListOperations.rightPop] with count.
+ *
+ * @author John Blum
+ * @since 3.2
+ */
+fun <K : Any, V : Any> ReactiveListOperations<K, V>.rightPopAsFlow(key: K, count:Long): Flow<V> =
+		rightPop(key, count).asFlow()
+
 /**
  * Coroutines variant of [ReactiveListOperations.rightPopAndLeftPush].
  *

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

@@ -15,10 +15,8 @@
  */
 package org.springframework.data.redis.core;
 
-import static org.assertj.core.api.Assertions.*;
-import static org.assertj.core.api.Assumptions.*;
-
-import reactor.test.StepVerifier;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assumptions.assumeThat;
 
 import java.time.Duration;
 import java.util.Collection;
@@ -35,11 +33,14 @@
 import org.springframework.data.redis.test.extension.parametrized.MethodSource;
 import org.springframework.data.redis.test.extension.parametrized.ParameterizedRedisTest;
 
+import reactor.test.StepVerifier;
+
 /**
  * Integration tests for {@link DefaultReactiveListOperations}.
  *
  * @author Mark Paluch
  * @author Christoph Strobl
+ * @author John Blum
  */
 @MethodSource("testParams")
 @SuppressWarnings("unchecked")
@@ -458,6 +459,38 @@ void leftPop() {
 		listOperations.leftPop(key).as(StepVerifier::create).expectNext(value2).verifyComplete();
 	}
 
+	@ParameterizedRedisTest // GH-2692
+	@SuppressWarnings("all")
+	void leftPopWithNullKey() {
+
+		assertThatIllegalArgumentException()
+			.isThrownBy(() -> this.listOperations.leftPop(null, 100L))
+			.withMessage("Key must not be null")
+			.withNoCause();
+	}
+
+	@ParameterizedRedisTest // GH-2692
+	void leftPopWithCount() {
+
+		assumeThat(this.valueFactory).isInstanceOf(ByteBufferObjectFactory.class);
+
+		K key = keyFactory.instance();
+		V value1 = valueFactory.instance();
+		V value2 = valueFactory.instance();
+		V value3 = valueFactory.instance();
+
+		listOperations.leftPushAll(key, value1, value2, value3)
+				.as(StepVerifier::create)
+				.expectNext(3L)
+				.verifyComplete();
+
+		listOperations.leftPop(key, 2)
+				.as(StepVerifier::create)
+				.expectNext(value3)
+				.expectNext(value2)
+				.verifyComplete();
+	}
+
 	@ParameterizedRedisTest // DATAREDIS-602
 	void rightPop() {
 
@@ -472,6 +505,38 @@ void rightPop() {
 		listOperations.rightPop(key).as(StepVerifier::create).expectNext(value2).verifyComplete();
 	}
 
+	@ParameterizedRedisTest // GH-2692
+	@SuppressWarnings("all")
+	void rightPopWithNullKey() {
+
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> this.listOperations.rightPop(null, 100L))
+				.withMessage("Key must not be null")
+				.withNoCause();
+	}
+
+	@ParameterizedRedisTest // GH-2692
+	void rightPopWithCount() {
+
+		assumeThat(this.valueFactory).isInstanceOf(ByteBufferObjectFactory.class);
+
+		K key = keyFactory.instance();
+		V value1 = valueFactory.instance();
+		V value2 = valueFactory.instance();
+		V value3 = valueFactory.instance();
+
+		listOperations.rightPushAll(key, value3, value2, value1)
+			.as(StepVerifier::create)
+			.expectNext(3L)
+			.verifyComplete();
+
+		listOperations.rightPop(key, 2)
+			.as(StepVerifier::create)
+			.expectNext(value1)
+			.expectNext(value2)
+			.verifyComplete();
+	}
+
 	@ParameterizedRedisTest // DATAREDIS-602
 	void leftPopWithTimeout() {
 

src/test/kotlin/org/springframework/data/redis/core/ReactiveListOperationsExtensionsUnitTests.kt

@@ -32,6 +32,7 @@ import java.time.Duration
  * @author Mark Paluch
  * @author Sebastien Deleuze
  * @author Wonwoo Lee
+ * @author John Blum
  */
 class ReactiveListOperationsExtensionsUnitTests {
 
@@ -290,11 +291,27 @@ class ReactiveListOperationsExtensionsUnitTests {
 		}
 	}
 
+	@Test // GH-2692
+	fun leftPopWithCount() {
+
+		val operations = mockk<ReactiveListOperations<String, String>>()
+
+		every { operations.leftPop(any(), any<Long>()) } returns Flux.just("foo", "bar", "baz")
+
+		runBlocking {
+			assertThat(operations.leftPopAsFlow("TestKey", 3L).toList()).containsExactly("foo", "bar", "baz")
+		}
+
+		verify {
+			operations.leftPop("TestKey", 3L)
+		}
+	}
+
 	@Test // DATAREDIS-937
 	fun blockingLeftPop() {
 
 		val operations = mockk<ReactiveListOperations<String, String>>()
-		every { operations.leftPop(any(), any()) } returns Mono.just("foo")
+		every { operations.leftPop(any(), any<Duration>()) } returns Mono.just("foo")
 
 		runBlocking {
 			assertThat(operations.leftPopAndAwait("foo", Duration.ofDays(1))).isEqualTo("foo")
@@ -320,11 +337,28 @@ class ReactiveListOperationsExtensionsUnitTests {
 		}
 	}
 
+	@Test // GH-2692
+	fun rightPopWithCount() {
+
+		val operations = mockk<ReactiveListOperations<String, String>>()
+
+		every { operations.rightPop(any(), any<Long>()) } returns Flux.just("foo", "bar", "baz")
+
+		runBlocking {
+			assertThat(operations.rightPopAsFlow("TestKey", 3L).toList())
+					.containsExactly("foo", "bar", "baz")
+		}
+
+		verify {
+			operations.rightPop("TestKey", 3L)
+		}
+	}
+
 	@Test // DATAREDIS-937
 	fun blockingRightPop() {
 
 		val operations = mockk<ReactiveListOperations<String, String>>()
-		every { operations.rightPop(any(), any()) } returns Mono.just("foo")
+		every { operations.rightPop(any(), any<Duration>()) } returns Mono.just("foo")
 
 		runBlocking {
 			assertThat(operations.rightPopAndAwait("foo", Duration.ofDays(1))).isEqualTo("foo")