Improve TTS engine listener

app/src/main/java/io/bartek/ttsserver/core/tts/engine/TTSEngine.kt

@@ -2,8 +2,6 @@ package io.bartek.ttsserver.core.tts.engine
 
 import android.content.Context
 import android.speech.tts.TextToSpeech
-import io.bartek.ttsserver.core.tts.exception.TTSException
-import io.bartek.ttsserver.core.tts.listener.Lock
 import io.bartek.ttsserver.core.tts.listener.TTSProcessListener
 import io.bartek.ttsserver.core.tts.model.TTSStream
 import io.bartek.ttsserver.core.tts.status.TTSStatus
@@ -32,23 +30,12 @@ class TTSEngine(
       file.takeIf { it.exists() }?.let { return it }
 
       val uuid = UUID.randomUUID().toString()
-      val lock = Lock()
-      tts.setOnUtteranceProgressListener(
-         TTSProcessListener(
-            uuid,
-            lock
-         )
-      )
+      val listener = TTSProcessListener(uuid)
+      tts.setOnUtteranceProgressListener(listener)
 
-      synchronized(lock) {
       tts.language = language
       tts.synthesizeToFile(text, null, file, uuid)
-         lock.wait()
-      }
-
-      if (!lock.success) {
-         throw TTSException()
-      }
+      listener.await()
 
       return file
    }
@@ -63,23 +50,12 @@ class TTSEngine(
       val file = createTempFile("tmp_tts_server", ".wav")
 
       val uuid = UUID.randomUUID().toString()
-      val lock = Lock()
-      tts.setOnUtteranceProgressListener(
-         TTSProcessListener(
-            uuid,
-            lock
-         )
-      )
+      val listener = TTSProcessListener(uuid)
+      tts.setOnUtteranceProgressListener(listener)
 
-      synchronized(lock) {
       tts.language = language
       tts.synthesizeToFile(text, null, file, uuid)
-         lock.wait()
-      }
-
-      if (!lock.success) {
-         throw TTSException()
-      }
+      listener.await()
 
       val stream = BufferedInputStream(FileInputStream(file))
       val length = file.length()
@@ -91,23 +67,12 @@ class TTSEngine(
 
    fun performTTS(text: String, language: Locale) {
       val uuid = UUID.randomUUID().toString()
-      val lock = Lock()
-      tts.setOnUtteranceProgressListener(
-         TTSProcessListener(
-            uuid,
-            lock
-         )
-      )
+      val listener = TTSProcessListener(uuid)
+      tts.setOnUtteranceProgressListener(listener)
 
-      synchronized(lock) {
       tts.language = language
       tts.speak(text, TextToSpeech.QUEUE_ADD, null, uuid)
-         lock.wait()
-      }
-
-      if (!lock.success) {
-         throw TTSException()
-      }
+      listener.await()
    }
 }
 

app/src/main/java/io/bartek/ttsserver/core/tts/listener/Lock.kt

@@ -1,5 +0,0 @@
-package io.bartek.ttsserver.core.tts.listener
-
-@Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN")
-// TODO: Investigate the Kotlin way to achieve the same
-data class Lock(var success: Boolean = false) : Object()

app/src/main/java/io/bartek/ttsserver/core/tts/listener/TTSProcessListener.kt

@@ -1,29 +1,29 @@
 package io.bartek.ttsserver.core.tts.listener
 
 import android.speech.tts.UtteranceProgressListener
+import io.bartek.ttsserver.core.tts.exception.TTSException
+import java.util.concurrent.LinkedBlockingQueue
 
-class TTSProcessListener(
-   private val uuid: String,
-   private val lock: Lock
-) : UtteranceProgressListener() {
+class TTSProcessListener(private val uuid: String) : UtteranceProgressListener() {
+   private val queue = LinkedBlockingQueue<Boolean>()
 
    override fun onDone(utteranceId: String?) {
       if (utteranceId == uuid) {
-         synchronized(lock) {
-            lock.success = true
-            lock.notifyAll()
-         }
+         queue.add(true)
       }
    }
 
    override fun onError(utteranceId: String?) {
       if (utteranceId == uuid) {
-         synchronized(lock) {
-            lock.success = false
-            lock.notifyAll()
-         }
+         queue.add(false)
       }
    }
 
    override fun onStart(utteranceId: String?) {}
+
+   fun await() {
+      if(!queue.take()) {
+         throw TTSException()
+      }
+   }
 }