#91 - Add RowsFetchSpec<T>.flow() extension.

Original pull request: #91.

Author: sdeleuze

src/main/kotlin/org/springframework/data/r2dbc/function/RowsFetchSpecExtensions.kt

@@ -15,8 +15,11 @@
  */
 package org.springframework.data.r2dbc.function
 
+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
 
 /**
  * Non-nullable Coroutines variant of [RowsFetchSpec.one].
@@ -50,5 +53,13 @@ suspend fun <T> RowsFetchSpec<T>.awaitFirst(): T =
 suspend fun <T> RowsFetchSpec<T>.awaitFirstOrNull(): T? =
 		first().awaitFirstOrNull()
 
-// TODO Coroutines variant of [RowsFetchSpec.all], depends on [kotlinx.coroutines#254](https://github.com/Kotlin/kotlinx.coroutines/issues/254).
-// suspend fun <T> RowsFetchSpec<T>.awaitAll() = all()...
+/**
+ * Coroutines [Flow] variant of [RowsFetchSpec.all].
+ *
+ * Backpressure is controlled by [batchSize] parameter that controls the size of in-flight elements
+ * and [org.reactivestreams.Subscription.request] size.
+ *
+ * @author Sebastien Deleuze
+ */
+@FlowPreview
+fun <T: Any> RowsFetchSpec<T>.flow(batchSize: Int = 1): Flow<T> = all().asFlow(batchSize)

src/test/kotlin/org/springframework/data/r2dbc/function/RowsFetchSpecExtensionsTests.kt

@@ -18,10 +18,13 @@ package org.springframework.data.r2dbc.function
 import io.mockk.every
 import io.mockk.mockk
 import io.mockk.verify
+import kotlinx.coroutines.FlowPreview
+import kotlinx.coroutines.flow.toList
 import kotlinx.coroutines.runBlocking
 import org.assertj.core.api.Assertions.assertThat
 import org.assertj.core.api.Assertions.assertThatExceptionOfType
 import org.junit.Test
+import reactor.core.publisher.Flux
 import reactor.core.publisher.Mono
 
 /**
@@ -150,4 +153,20 @@ class RowsFetchSpecExtensionsTests {
 			spec.first()
 		}
 	}
+
+	@Test // gh-91
+	@FlowPreview
+	fun allAsFlow() {
+
+		val spec = mockk<RowsFetchSpec<String>>()
+		every { spec.all() } returns Flux.just("foo", "bar", "baz")
+
+		runBlocking {
+			assertThat(spec.flow().toList()).contains("foo", "bar", "baz")
+		}
+
+		verify {
+			spec.all()
+		}
+	}
 }