Add RSocketRequester coroutines extensions

See gh-22780

spring-messaging/src/main/kotlin/org/springframework/messaging/rsocket/RSocketRequesterExtensions.kt

@@ -0,0 +1,94 @@
+/*
+ * Copyright 2002-2019 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
+ *
+ *      https://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.messaging.rsocket
+
+import io.rsocket.transport.ClientTransport
+import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.reactive.awaitFirstOrNull
+import kotlinx.coroutines.reactive.awaitSingle
+import kotlinx.coroutines.reactive.flow.asFlow
+import kotlinx.coroutines.reactive.flow.asPublisher
+import org.springframework.core.ParameterizedTypeReference
+import java.net.URI
+
+/**
+ * Coroutines variant of [RSocketRequester.Builder.connect].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+suspend fun RSocketRequester.Builder.connectAndAwait(transport: ClientTransport): RSocketRequester =
+		connect(transport).awaitSingle()
+
+/**
+ * Coroutines variant of [RSocketRequester.Builder.connectTcp].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+suspend fun RSocketRequester.Builder.connectTcpAndAwait(host: String, port: Int): RSocketRequester =
+		connectTcp(host, port).awaitSingle()
+
+/**
+ * Coroutines variant of [RSocketRequester.Builder.connectWebSocket].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+suspend fun RSocketRequester.Builder.connectWebSocketAndAwait(uri: URI): RSocketRequester =
+		connectWebSocket(uri).awaitSingle()
+
+
+/**
+ * Kotlin [Flow] variant of [RSocketRequester.RequestSpec.data].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+@FlowPreview
+fun <T : Any> RSocketRequester.RequestSpec.dataFlow(data: Flow<T>): RSocketRequester.ResponseSpec =
+		data(data.asPublisher(), object : ParameterizedTypeReference<T>() {})
+
+/**
+ * Coroutines variant of [RSocketRequester.ResponseSpec.send].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+suspend fun RSocketRequester.ResponseSpec.sendAndAwait() {
+	send().awaitFirstOrNull()
+}
+
+/**
+ * Coroutines variant of [RSocketRequester.ResponseSpec.retrieveMono].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+suspend fun <T : Any> RSocketRequester.ResponseSpec.retrieveAndAwait(): T =
+		retrieveMono(object : ParameterizedTypeReference<T>() {}).awaitSingle()
+
+/**
+ * Coroutines variant of [RSocketRequester.ResponseSpec.retrieveFlux].
+ *
+ * @author Sebastien Deleuze
+ * @since 5.2
+ */
+@FlowPreview
+fun <T : Any> RSocketRequester.ResponseSpec.retrieveFlow(batchSize: Int = 1): Flow<T> =
+		retrieveFlux(object : ParameterizedTypeReference<T>() {}).asFlow(batchSize)