refactor: simplify schema name retrieval in validation messages

Signed-off-by: Zhiwei Liang <zhiwei.liang@zliang.me>

Author: ChihweiLHBird

modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiSchemaValidations.java

@@ -96,13 +96,9 @@ private static ValidationRule.Result checkNullType(SchemaWrapper schemaWrapper)
                 // OAS spec is 3.0.x
                 if (ModelUtils.isNullType(schema)) {
                     result = new ValidationRule.Fail();
-                    String name = schema.getName();
-                    if (name == null) {
-                        name = schema.getTitle();
-                    }
                     result.setDetails(String.format(Locale.ROOT,
                             "Schema '%s' uses a 'null' type, which is specified in OAS 3.1 and above, but OAS document is version %s",
-                            name, schemaWrapper.getOpenAPI().getOpenapi()));
+                            nameOf(schema), schemaWrapper.getOpenAPI().getOpenapi()));
                     return result;
                 }
             }
@@ -126,20 +122,22 @@ private static ValidationRule.Result checkNullableAttribute(SchemaWrapper schema
             if (version.atLeast("3.1")) {
                 if (ModelUtils.isNullable(schema)) {
                     result = new ValidationRule.Fail();
-                    String name = schema.getName();
-                    if (name == null) {
-                        name = schema.getTitle();
-                    }
                     result.setDetails(String.format(Locale.ROOT,
                             "OAS document is version '%s'. Schema '%s' uses 'nullable' attribute, which has been deprecated in OAS 3.1.",
-                            schemaWrapper.getOpenAPI().getOpenapi(), name));
+                            schemaWrapper.getOpenAPI().getOpenapi(), nameOf(schema)));
                     return result;
                 }
             }
         }
         return result;
     }
 
+    private static String nameOf(Schema schema) {
+        if (schema.getName() != null) return schema.getName();
+        if (schema.getTitle() != null) return schema.getTitle();
+        return "(unnamed)";
+    }
+
     // The set of valid OAS values for the 'type' attribute.
     private static Set<String> validTypes = new HashSet<String>(
             Arrays.asList("null", "boolean", "object", "array", "number", "string", "integer"));
@@ -157,13 +155,9 @@ private static ValidationRule.Result checkInvalidType(SchemaWrapper schemaWrappe
         ValidationRule.Result result = ValidationRule.Pass.empty();
         if (schema.getType() != null && !validTypes.contains(schema.getType())) {
             result = new ValidationRule.Fail();
-            String name = schema.getName();
-            if (name == null) {
-                name = schema.getTitle();
-            }
             result.setDetails(String.format(Locale.ROOT,
                     "Schema '%s' uses the '%s' type, which is not a valid type.",
-                    name, schema.getType()));
+                    nameOf(schema), schema.getType()));
             return result;
         }
         return result;