introduce interfaces for state/feedback topics

src/HomematicSwitchItem.ts

@@ -2,8 +2,9 @@ import * as logger from './log'
 import { mqttHandler } from './MqttDispatcher'
 import { AHomematicItem } from './AHomematicItem'
 import { SwitchExport, ExportType } from './Export'
+import { HasStateAndFeedbackTopic } from './AItem';
 
-export class HomematicSwitchItem extends AHomematicItem {
+export class HomematicSwitchItem extends AHomematicItem implements HasStateAndFeedbackTopic {
     private oldState: string|undefined
     private state: string
     private actionTopic: string
@@ -12,6 +13,14 @@ export class HomematicSwitchItem extends AHomematicItem {
     private stateTopic: string
     private type: string
 
+    getStateTopic() : string {
+        return this.stateTopic
+    }
+
+    getStateFeedbackTopic() : string {
+        return this.stateFeedbackTopic
+    }
+
     constructor(floor: string, room: string, item: string, label: string, hmId: number, type: string = 'bulb') {
         super(floor, room, item, label, hmId)
         this.stateTopic = `${this.topicFirstPart}/state`