feature: add profile for keyword detector model

src/main/java/io/spokestack/spokestack/profile/VADTriggerKeywordASR.java

@@ -0,0 +1,56 @@
+package io.spokestack.spokestack.profile;
+
+import io.spokestack.spokestack.PipelineProfile;
+import io.spokestack.spokestack.SpeechPipeline;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * A speech pipeline profile that uses voice activity detection to activate
+ * ASR based on keyword detection.
+ *
+ * <p>
+ * The keyword detector requires extra configuration, which must be
+ * added to the pipeline build process separately from this profile:
+ * </p>
+ *
+ * <ul>
+ *   <li>
+ *      <b>keyword-classes</b> (string): comma-separated ordered
+ *      list of class names for the keywords; the name corresponding to the
+ *      most likely class will be returned in the transcript field when the
+ *      recognition event is raised
+ *   </li>
+ *   <li>
+ *      <b>keyword-filter-path</b> (string): file system path to the
+ *      "filter" Tensorflow-Lite model
+ *   </li>
+ *   <li>
+ *      <b>keyword-encode-path</b> (string): file system path to the
+ *      "encode" Tensorflow-Lite model
+ *   </li>
+ *   <li>
+ *      <b>keyword-detect-path</b> (string): file system path to the
+ *      "detect" Tensorflow-Lite model
+ *   </li>
+ * </ul>
+ *
+ * @see io.spokestack.spokestack.asr.KeywordRecognizer
+ */
+public class VADTriggerKeywordASR implements PipelineProfile {
+    @Override
+    public SpeechPipeline.Builder apply(SpeechPipeline.Builder builder) {
+        List<String> stages = new ArrayList<>();
+        stages.add("io.spokestack.spokestack.webrtc.AutomaticGainControl");
+        stages.add("io.spokestack.spokestack.webrtc.AcousticNoiseSuppressor");
+        stages.add("io.spokestack.spokestack.webrtc.VoiceActivityDetector");
+        stages.add("io.spokestack.spokestack.webrtc.VoiceActivityTrigger");
+        stages.add("io.spokestack.spokestack.ActivationTimeout");
+        stages.add("io.spokestack.spokestack.asr.KeywordRecognizer");
+
+        return builder
+              .setInputClass("io.spokestack.spokestack.android.MicrophoneInput")
+              .setStageClasses(stages);
+    }
+}

src/test/java/io/spokestack/spokestack/SpeechPipelineTest.java

@@ -28,6 +28,7 @@ public class SpeechPipelineTest implements OnSpeechEventListener {
           io.spokestack.spokestack.profile.VADTriggerAndroidASR.class,
           io.spokestack.spokestack.profile.VADTriggerAzureASR.class,
           io.spokestack.spokestack.profile.VADTriggerGoogleASR.class,
+          io.spokestack.spokestack.profile.VADTriggerKeywordASR.class,
           io.spokestack.spokestack.profile.VADTriggerSpokestackASR.class
     );