[hotfix] Improve handling of data lake measures in API

streampipes-model/src/main/java/org/apache/streampipes/model/datalake/DataLakeMeasure.java

@@ -35,7 +35,9 @@ public class DataLakeMeasure {
   public static final String ASSERTION_ERROR_MESSAGE = "timestamp field requires a stream prefix (e.g. s0::timestamp)";
   private static final String STREAM_PREFIX_DELIMITER = "::";
 
+  @JsonProperty("elementId")
   protected @SerializedName("_id") String elementId;
+
   @JsonProperty("_rev")
   private @SerializedName("_rev") String rev;
 

streampipes-platform-services/src/main/java/org/apache/streampipes/ps/DataLakeMeasureResourceV4.java

@@ -35,6 +35,8 @@
 import jakarta.ws.rs.core.MediaType;
 import jakarta.ws.rs.core.Response;
 
+import java.util.Objects;
+
 @Path("/v4/datalake/measure")
 public class DataLakeMeasureResourceV4 extends AbstractAuthGuardedRestResource {
 
@@ -58,7 +60,12 @@ public Response addDataLake(DataLakeMeasure dataLakeMeasure) {
   @Produces(MediaType.APPLICATION_JSON)
   @Path("{id}")
   public Response getDataLakeMeasure(@PathParam("id") String elementId) {
-    return ok(this.dataLakeMeasureManagement.getById(elementId));
+    var measure = this.dataLakeMeasureManagement.getById(elementId);
+    if (Objects.nonNull(measure)) {
+      return ok(measure);
+    } else {
+      return notFound();
+    }
   }
 
   @PUT

streampipes-rest-shared/src/main/java/org/apache/streampipes/rest/shared/impl/AbstractSharedRestInterface.java

@@ -35,6 +35,10 @@ protected <T> Response notFound(T entity) {
     return error(entity, 404);
   }
 
+  protected <T> Response notFound() {
+    return Response.status(404).build();
+  }
+
   protected <T> Response serverError(T entity) {
     return error(entity, 500);
   }

streampipes-storage-couchdb/src/main/java/org/apache/streampipes/storage/couchdb/impl/DataLakeStorageImpl.java

@@ -38,8 +38,7 @@ public boolean storeDataLakeMeasure(DataLakeMeasure measure) {
 
   @Override
   public List<DataLakeMeasure> getAllDataLakeMeasures() {
-    List<DataLakeMeasure> dataLakeMeasures = findAll();
-    return dataLakeMeasures;
+    return findAll();
   }
 
   @Override