Add exception handling playground files

Author: LukasLechnerDev

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/playground/flow/exceptionhandling/1_try-catch.kt

@@ -3,20 +3,39 @@ package com.lukaslechner.coroutineusecasesonandroid.playground.flow.exceptionhan
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.flow.Flow
 import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.onCompletion
 import kotlinx.coroutines.launch
 
 suspend fun main(): Unit = coroutineScope {
 
     launch {
-        stocksFlow()
-            .collect { stock ->
-                println("Collected $stock")
+        val stocksFlow = stocksFlow()
+            .map {
+                throw Exception("Exception in Map")
             }
+
+        try {
+            stocksFlow
+                .onCompletion { cause ->
+                    if (cause == null) {
+                        println("Flow completed successfully!")
+                    } else {
+                        println("Flow completed exceptionally with $cause")
+                    }
+                }
+                .collect { stock ->
+                    println("Collected $stock")
+                }
+        } catch (e: Exception) {
+            println("Handle Exception in catch block - $e")
+        }
     }
 }
 
 private fun stocksFlow(): Flow<String> = flow {
     emit("Apple")
     emit("Microsoft")
-    throw Exception("Network request failed")
+
+    throw Exception("Network Request Failed!")
 }

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/playground/flow/exceptionhandling/2_catch.kt

@@ -0,0 +1,37 @@
+package com.lukaslechner.coroutineusecasesonandroid.playground.flow.exceptionhandling
+
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.onCompletion
+import kotlinx.coroutines.launch
+
+suspend fun main(): Unit = coroutineScope {
+
+    launch {
+        val stocksFlow = stocksFlow()
+
+        stocksFlow
+            .onCompletion { cause ->
+                if (cause == null) {
+                    println("Flow completed successfully!")
+                } else {
+                    println("Flow completed exceptionally with $cause")
+                }
+            }
+            .catch { throwable ->
+                println("Handle exception in catch() operator $throwable")
+            }
+            .collect { stock ->
+                println("Collected $stock")
+            }
+    }
+}
+
+private fun stocksFlow(): Flow<String> = flow {
+    emit("Apple")
+    emit("Microsoft")
+
+    throw Exception("Network Request Failed!")
+}

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/playground/flow/exceptionhandling/3_emit_single_value.kt

@@ -0,0 +1,38 @@
+package com.lukaslechner.coroutineusecasesonandroid.playground.flow.exceptionhandling
+
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.catch
+import kotlinx.coroutines.flow.flow
+import kotlinx.coroutines.flow.onCompletion
+import kotlinx.coroutines.launch
+
+suspend fun main(): Unit = coroutineScope {
+
+    launch {
+        val stocksFlow = stocksFlow()
+
+        stocksFlow
+            .onCompletion { cause ->
+                if (cause == null) {
+                    println("Flow completed successfully!")
+                } else {
+                    println("Flow completed exceptionally with $cause")
+                }
+            }
+            .catch { throwable ->
+                println("Handle exception in catch() operator $throwable")
+                emit("Default Stock")
+            }
+            .collect { stock ->
+                println("Collected $stock")
+            }
+    }
+}
+
+private fun stocksFlow(): Flow<String> = flow {
+    emit("Apple")
+    emit("Microsoft")
+
+    throw Exception("Network Request Failed!")
+}

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/playground/flow/exceptionhandling/4_fallback_flow.kt

@@ -0,0 +1,43 @@
+package com.lukaslechner.coroutineusecasesonandroid.playground.flow.exceptionhandling
+
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.*
+import kotlinx.coroutines.launch
+
+suspend fun main(): Unit = coroutineScope {
+
+    launch {
+        val stocksFlow = stocksFlow()
+
+        stocksFlow
+            .onCompletion { cause ->
+                if (cause == null) {
+                    println("Flow completed successfully!")
+                } else {
+                    println("Flow completed exceptionally with $cause")
+                }
+            }
+            .catch { throwable ->
+                println("Handle exception in catch() operator $throwable")
+                emitAll(fallbackFlow())
+            }.catch { throwable ->
+                println("Handle exception in 2. catch() operator $throwable")
+            }
+            .collect { stock ->
+                println("Collected $stock")
+            }
+    }
+}
+
+private fun stocksFlow(): Flow<String> = flow {
+    emit("Apple")
+    emit("Microsoft")
+
+    throw Exception("Network Request Failed!")
+}
+
+private fun fallbackFlow(): Flow<String> = flow {
+    emit("Fallback Stock")
+
+    throw Exception("Exception in Fallback Flow")
+}

app/src/main/java/com/lukaslechner/coroutineusecasesonandroid/playground/flow/exceptionhandling/5_exception_in_collect.kt

@@ -0,0 +1,32 @@
+package com.lukaslechner.coroutineusecasesonandroid.playground.flow.exceptionhandling
+
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.*
+
+suspend fun main(): Unit = coroutineScope {
+
+    val stocksFlow = stocksFlow()
+
+    stocksFlow
+        .onCompletion { cause ->
+            if (cause == null) {
+                println("Flow completed successfully!")
+            } else {
+                println("Flow completed exceptionally with $cause")
+            }
+        }
+        .onEach { stock ->
+            throw Exception("Exception in collect{}")
+            println("Collected $stock")
+        }.catch { throwable ->
+            println("Handle exception in catch() operator $throwable")
+        }
+        .launchIn(this)
+}
+
+private fun stocksFlow(): Flow<String> = flow {
+    emit("Apple")
+    emit("Microsoft")
+
+    throw Exception("Network Request Failed!")
+}