CIRC-2051 move common validation to separate method

src/main/java/org/folio/circulation/resources/AllowedServicePointsResource.java

@@ -96,18 +96,8 @@ private static Result<AllowedServicePointsRequest> buildRequest(RoutingContext r
         requestId);
       errors.add(String.format("Request ID is not a valid UUID: %s.", requestId));
     }
-    if (useStubItem != null && !"true".equals(useStubItem) && !"false".equals(useStubItem)) {
-      log.warn("validateAllowedServicePointsRequest:: useStubItem is not a valid boolean: {}",
-        useStubItem);
-      errors.add(String.format("useStubItem is not a valid boolean: %s.", useStubItem));
-    }
-    if (ecsRequestRouting != null && !"true".equals(ecsRequestRouting)
-      && !"false".equals(ecsRequestRouting)) {
-
-      log.warn("validateAllowedServicePointsRequest:: ecsRequestRouting is not a valid boolean: {}",
-        ecsRequestRouting);
-      errors.add(String.format("ecsRequestRouting is not a valid boolean: %s.", ecsRequestRouting));
-    }
+    validateBoolean(useStubItem, "useStubItem", errors);
+    validateBoolean(ecsRequestRouting, "ecsRequestRouting", errors);
     // Checking parameter combinations
     boolean allowedCombinationOfParametersDetected = false;
 
@@ -149,6 +139,14 @@ private static Result<AllowedServicePointsRequest> buildRequest(RoutingContext r
       requestId, Boolean.parseBoolean(useStubItem), Boolean.parseBoolean(ecsRequestRouting)));
   }
 
+  private static void validateBoolean(String parameter, String parameterName, List<String> errors) {
+    if (parameter != null && !"true".equals(parameter) && !"false".equals(parameter)) {
+      log.warn("validateBoolean:: {} is not a valid boolean: {}",
+        parameterName, parameter);
+      errors.add(String.format("%s is not a valid boolean: %s.", parameterName, parameter));
+    }
+  }
+
   private static JsonObject toJson(Map<RequestType, Set<AllowedServicePoint>> allowedServicePoints) {
     log.debug("toJson:: parameters: allowedServicePoints={}", () -> asJson(allowedServicePoints));
     JsonObject response = new JsonObject();