[voice] Add interface to represent a remote keyword spotter (#3564)

Signed-off-by: Miguel Álvarez <miguelwork92@gmail.com>

bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/KSEdgeService.java

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) 2010-2023 Contributors to the openHAB project
+ *
+ * See the NOTICE file(s) distributed with this work for additional
+ * information.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ */
+package org.openhab.core.voice;
+
+import java.util.Locale;
+
+import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.openhab.core.audio.AudioStream;
+
+/**
+ * This is the interface that an edge keyword spotting service has to implement.
+ * Used to register a keyword spotting service that is running on a remote device.
+ *
+ * @author Miguel Álvarez - Initial contribution
+ */
+@NonNullByDefault
+public interface KSEdgeService extends KSService {
+
+    /**
+     * This method links the remote keyword spotting process to a consumer.
+     *
+     * The method is supposed to return fast.
+     *
+     * @param ksListener Non-null {@link KSListener} that {@link KSEvent} events target
+     * @throws KSException if any parameter is invalid or a problem occurs
+     */
+    KSServiceHandle spot(KSListener ksListener) throws KSException;
+
+    @Override
+    default KSServiceHandle spot(KSListener ksListener, AudioStream audioStream, Locale locale, String keyword)
+            throws KSException {
+        throw new KSException("An edge keyword spotter is not meant to process audio in the server");
+    }
+}

bundles/org.openhab.core.voice/src/main/java/org/openhab/core/voice/internal/DialogProcessor.java

@@ -34,6 +34,7 @@ import org.openhab.core.items.ItemUtil;
 import org.openhab.core.items.events.ItemEventFactory;
 import org.openhab.core.library.types.OnOffType;
 import org.openhab.core.voice.DialogContext;
+import org.openhab.core.voice.KSEdgeService;
 import org.openhab.core.voice.KSErrorEvent;
 import org.openhab.core.voice.KSEvent;
 import org.openhab.core.voice.KSException;
@@ -164,9 +165,13 @@ public class DialogProcessor implements KSListener, STTListener {
                 return;
             }
             try {
-                AudioStream stream = dialogContext.source().getInputStream(fmt);
+                if (ksService instanceof KSEdgeService) {
-                streamKS = stream;
+                    ((KSEdgeService) ksService).spot(this);
-                ksServiceHandle = ksService.spot(this, stream, dialogContext.locale(), keyword);
+                } else {
+                    AudioStream stream = dialogContext.source().getInputStream(fmt);
+                    streamKS = stream;
+                    ksServiceHandle = ksService.spot(this, stream, dialogContext.locale(), keyword);
+                }
                 playStartSound();
             } catch (AudioException e) {
                 logger.warn("Encountered audio error: {}", e.getMessage());