Added Suspendable Open Calls (#69)

* Added Suspendable Open Calls

- updated README.md
- added equivalent suspend aware open csv calls
- added respectively suspend open call tests

* Fixed Comment Issue

Co-authored-by: Victor Harlan D. Lacson <[email protected]>

README.md

@@ -112,6 +112,19 @@ csvReader().open("test.csv") {
 }
 ```
 
+#### Read in a `Suspending Function`
+```kotlin
+csvReader().openAsync("test.csv") {
+ val container = mutalbeListOf<List<String>>()
+ delay(100) //other suspending task
+ readAllAsSequence().asFlow().collect { row ->
+ delay(100) // other suspending task
+ container(row) 
+ }
+}
+```
+Note: `openAsync` can be and only be accessed through a `coroutine` or another `suspending` function
+
 #### Customize
 
 When you create CsvReader, you can choose read options.

build.gradle.kts

@@ -69,6 +69,7 @@ kotlin {
  dependencies {
  implementation(kotlin("test"))
  implementation(kotlin("test-junit"))
+ implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.2")
  implementation("io.kotlintest:kotlintest-runner-junit5:3.3.2")
  }
  }

src/jvmMain/kotlin/com/github/doyaaaaaken/kotlincsv/client/CsvReader.kt

@@ -97,6 +97,25 @@ actual class CsvReader actual constructor(
  return open(File(fileName), read)
  }
 
+ /**
+ * open inputStreamReader and execute reading process on a **suspending** function.
+ *
+ * If you want to control read flow precisely, use this method.
+ * Otherwise, use utility method (e.g. CsvReader.readAll ).
+ *
+ * Usage example:
+ * <pre>
+ * val data: Sequence<List<String?>> = csvReader().openAsync("test.csv") {
+ * readAllAsSequence()
+ * .map { fields -> fields.map { it.trim() } }
+ * .map { fields -> fields.map { if(it.isBlank()) null else it } }
+ * }
+ * </pre>
+ */
+ suspend fun <T> openAsync(fileName: String, read: suspend CsvFileReader.() -> T): T {
+ return openAsync(File(fileName), read)
+ }
+
  /**
  * open inputStreamReader and execute reading process.
  *
@@ -112,7 +131,21 @@ actual class CsvReader actual constructor(
  }
 
  /**
- * open inputStreamReader and execute reading process.
+ * open inputStreamReader and execute reading process on a **suspending** function.
+ *
+ * If you want to control read flow precisely, use this method.
+ * Otherwise, use utility method (e.g. CsvReader.readAll ).
+ *
+ * Usage example:
+ * @see openAsync method
+ */
+ suspend fun <T> openAsync(file: File, read: suspend CsvFileReader.() -> T): T {
+ val br = file.inputStream().bufferedReader(charsetCode)
+ return openAsync(br, read)
+ }
+
+ /**
+ * open inputStreamReader and execute reading process on a **suspending** function.
  *
  * If you want to control read flow precisely, use this method.
  * Otherwise, use utility method (e.g. CsvReader.readAll ).
@@ -125,10 +158,31 @@ actual class CsvReader actual constructor(
  return open(br, read)
  }
 
+ /**
+ * open inputStreamReader and execute reading process on a **suspending** function.
+ *
+ * If you want to control read flow precisely, use this method.
+ * Otherwise, use utility method (e.g. CsvReader.readAll ).
+ *
+ * Usage example:
+ * @see openAsync method
+ */
+ suspend fun <T> openAsync(ips: InputStream, read: suspend CsvFileReader.()-> T): T {
+ val br = ips.bufferedReader(charsetCode)
+ return openAsync(br, read)
+ }
+
  private fun <T> open(br: BufferedReader, doRead: CsvFileReader.() -> T): T {
  val reader = CsvFileReader(ctx, br)
  return reader.use {
  reader.doRead()
  }
  }
+
+ private suspend fun <T> openAsync(br: BufferedReader, doRead: suspend CsvFileReader.() -> T): T {
+ val reader = CsvFileReader(ctx, br)
+ return reader.use {
+ reader.doRead()
+ }
+ }
 }

src/jvmTest/kotlin/com/github/doyaaaaaken/kotlincsv/client/CsvReaderTest.kt

@@ -9,6 +9,8 @@ import com.github.doyaaaaaken.kotlincsv.util.Const
 import com.github.doyaaaaaken.kotlincsv.util.MalformedCSVException
 import io.kotlintest.shouldBe
 import io.kotlintest.shouldThrow
+import kotlinx.coroutines.flow.asFlow
+import kotlinx.coroutines.flow.collect
 import java.io.File
 import kotlin.test.assertEquals
 
@@ -253,6 +255,44 @@ class CsvReaderTest : WordSpec() {
  }
  rows shouldBe listOf(listOf("a", "b", "c"), listOf("d", "e", "f"))
  }
+ "execute as suspending function" should {
+ "open suspending method (with fileName argument)" {
+ val rows = csvReader().openAsync("src/jvmTest/resources/testdata/csv/simple.csv") {
+ val row1 = readNext()
+ val row2 = readNext()
+ listOf(row1, row2)
+ }
+ rows shouldBe listOf(listOf("a", "b", "c"), listOf("d", "e", "f"))
+ }
+ "open suspending method (with file argument)" {
+ val file = readTestDataFile("simple.csv")
+ val rows = csvReader().openAsync(file) {
+ val row1 = readNext()
+ val row2 = readNext()
+ listOf(row1, row2)
+ }
+ rows shouldBe listOf(listOf("a", "b", "c"), listOf("d", "e", "f"))
+ }
+ "open suspending method (with InputStream argument)" {
+ val fileStream = readTestDataFile("simple.csv").inputStream()
+ val rows = csvReader().openAsync(fileStream) {
+ val row1 = readNext()
+ val row2 = readNext()
+ listOf(row1, row2)
+ }
+ rows shouldBe listOf(listOf("a", "b", "c"), listOf("d", "e", "f"))
+ }
+ "validate test as flow" {
+ val fileStream = readTestDataFile("simple.csv").inputStream()
+ val rows = mutableListOf<List<String>>()
+ csvReader().openAsync(fileStream) {
+ readAllAsSequence().asFlow().collect {
+ rows.add(it)
+ }
+ }
+ rows shouldBe listOf(listOf("a", "b", "c"), listOf("d", "e", "f"))
+ }
+ }
  }
 }