removed old string return value

Author: sharhio

src/ext/java/org/opentripplanner/ext/vectortiles/layers/stops/DigitransitRealtimeStopPropertyMapper.java

@@ -35,13 +35,7 @@ protected Collection<KeyValue> map(RegularStop stop) {
     Collection<KeyValue> sharedKeyValues = getBaseKeyValues(stop, i18NStringMapper, transitService);
     return ListUtils.combine(
       sharedKeyValues,
-      List.of(
-        new KeyValue("closedByServiceAlert", noServiceAlert),
-        new KeyValue(
-          "parentStation",
-          stop.getParentStation() != null ? stop.getParentStation().getId() : null
-        )
-      )
+      List.of(new KeyValue("closedByServiceAlert", noServiceAlert))
     );
   }
 }

src/ext/java/org/opentripplanner/ext/vectortiles/layers/stops/DigitransitStopPropertyMapper.java

@@ -35,16 +35,7 @@ protected static DigitransitStopPropertyMapper create(
 
   @Override
   protected Collection<KeyValue> map(RegularStop stop) {
-    Collection<KeyValue> sharedKeyValues = getBaseKeyValues(stop, i18NStringMapper, transitService);
-    return ListUtils.combine(
-      sharedKeyValues,
-      List.of(
-        new KeyValue(
-          "parentStation",
-          stop.getParentStation() != null ? stop.getParentStation().getId() : "null"
-        )
-      )
-    );
+    return getBaseKeyValues(stop, i18NStringMapper, transitService);
   }
 
   protected static Collection<KeyValue> getBaseKeyValues(
@@ -59,7 +50,11 @@ protected static Collection<KeyValue> getBaseKeyValues(
       new KeyValue("platform", stop.getPlatformCode()),
       new KeyValue("desc", i18NStringMapper.mapToApi(stop.getDescription())),
       new KeyValue("type", getType(transitService, stop)),
-      new KeyValue("routes", getRoutes(transitService, stop))
+      new KeyValue("routes", getRoutes(transitService, stop)),
+      new KeyValue(
+        "parentStation",
+        stop.getParentStation() != null ? stop.getParentStation().getId() : null
+      )
     );
   }