Rendez-vous channel implementation

jeorg-kotlin-coroutines/coroutines-crums-group-1/src/main/kotlin/org/jesperancinha/ktd/ElementsSendReceiveChannels.kt

@@ -0,0 +1,74 @@
+package org.jesperancinha.ktd
+
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.Channel
+import java.util.*
+import java.util.concurrent.LinkedBlockingQueue
+
+
+private suspend fun fetchItem() = withContext(Dispatchers.Default) { "ITEM-${UUID.randomUUID()}" }
+private const val PRODUCTION_COST_MS = 200L
+
+class ElementsSendReceiveBlockingChannel {
+
+    private val linkedBlockingQueue by lazy { LinkedBlockingQueue<String>(100) }
+    private suspend fun produceItems() {
+        val item = fetchItem()
+        delay(PRODUCTION_COST_MS)
+        linkedBlockingQueue.add(item)
+        delay(PRODUCTION_COST_MS)
+        linkedBlockingQueue.add(item)
+    }
+
+    private suspend fun receiveItems() {
+        do {
+            val item = withContext(Dispatchers.IO) {
+                linkedBlockingQueue.take()
+            }
+            println("LinkedBlockingQueue received item $item!")
+        } while (!linkedBlockingQueue.isEmpty())
+    }
+
+    suspend fun doMain() = coroutineScope {
+        val receiveTask = async { receiveItems() }
+        val produceTask = async { produceItems() }
+        produceTask.await()
+        receiveTask.await()
+    }
+}
+
+class ElementsSendReceiveChannel {
+
+    private val channel by lazy { Channel<String>(2) }
+
+    private suspend fun produceItems() {
+        val item = fetchItem()
+        delay(PRODUCTION_COST_MS)
+        channel.send(item)
+        delay(PRODUCTION_COST_MS)
+        channel.send(item)
+    }
+
+
+    private suspend fun receiveItems() {
+        repeat(2) {
+            val item = channel.receive()
+            println("Channel received item $item!")
+        }
+    }
+
+    suspend fun doMain() = coroutineScope {
+        launch { produceItems() }
+        launch { receiveItems() }
+    }
+}
+
+class ElementsSendReceiveRunner {
+    companion object {
+        @JvmStatic
+        fun main(args: Array<String>): Unit = runBlocking {
+            ElementsSendReceiveBlockingChannel().doMain()
+            ElementsSendReceiveChannel().doMain()
+        }
+    }
+}