fix nullability customizer

src/main/java/it/aboutbits/springboot/toolbox/swagger/customization/default_not_null/NullableCustomizer.java

@@ -5,13 +5,13 @@
 import org.jspecify.annotations.NullMarked;
 import org.springdoc.core.customizers.OpenApiCustomizer;
 
+import java.lang.annotation.Annotation;
+import java.lang.reflect.AnnotatedType;
 import java.util.ArrayList;
 import java.util.Map;
 
 @NullMarked
 public class NullableCustomizer implements OpenApiCustomizer {
-    public static final String NULLABLE_MARKER = "NULLABLE";
-
     @Override
     @SuppressWarnings("unchecked")
     public void customise(OpenAPI openApi) {
@@ -23,57 +23,129 @@ public void customise(OpenAPI openApi) {
                     var requiredProperties = new ArrayList<String>();
                     if (((Schema<?>) schema).getProperties() != null) {
                         var properties = ((Schema<?>) schema).getProperties();
-                        processProperties(properties, requiredProperties);
+                        processProperties(schema.getName(), properties, requiredProperties);
                     }
                     if (schema.getAllOf() != null) {
                         schema.getAllOf().forEach(allOfSchema -> {
                             var allOfSchemaTyped = (Schema<?>) allOfSchema;
                             if (allOfSchemaTyped.getProperties() != null) {
                                 var properties = allOfSchemaTyped.getProperties();
-                                processProperties(properties, requiredProperties);
+                                processProperties(schema.getName(), properties, requiredProperties);
                             }
                         });
                     }
                     schema.setRequired(requiredProperties);
                 });
     }
 
-    private static void processProperties(Map<String, Schema> properties, ArrayList<String> requiredProperties) {
+    @SuppressWarnings("rawtypes")
+    private static void processProperties(
+            String modelFqn,
+            Map<String, Schema> properties,
+            ArrayList<String> requiredProperties
+    ) {
+        var cls = loadClass(modelFqn);
+        if (cls == null) {
+            return;
+        }
+
         properties.forEach((propertyName, property) -> {
-            var isNullable = isNullable(property);
+            var isNullable = isNullable(cls, propertyName);
 
             if (!isNullable) {
                 requiredProperties.add(propertyName);
             } else {
                 requiredProperties.remove(propertyName);
             }
-            if (property.getTitle() != null && property.getTitle().equals(NULLABLE_MARKER)) {
-                property.setTitle(null);
-            }
-            if (property.get$ref() != null) {
-                property.set$ref(property.get$ref().replace(NULLABLE_MARKER, ""));
-            }
-            if (property.getItems() != null && property.getItems().get$ref() != null) {
-                property.getItems().set$ref(property.getItems().get$ref().replace(NULLABLE_MARKER, ""));
-            }
         });
     }
 
-    private static boolean isNullable(Schema<?> property) {
-        if (property.getTitle() != null && property.getTitle().equals(NULLABLE_MARKER)) {
-            return true;
+    @org.jspecify.annotations.Nullable
+    private static Class<?> loadClass(String fqn) {
+        try {
+            return Class.forName(fqn);
+        } catch (ClassNotFoundException _) {
+            // if this does not work, we probably have a parameterized type where the fqn is concatenated
         }
 
-        if (property.get$ref() != null && property.get$ref().endsWith(NULLABLE_MARKER)) {
-            return true;
+        var lastDotIndex = -1;
+        for (var i = 0; i <= fqn.length(); i++) {
+            if (i == fqn.length() || fqn.charAt(i) == '.') {
+                var fullPart = fqn.substring(lastDotIndex + 1, i);
+                if (!fullPart.isEmpty() && Character.isUpperCase(fullPart.charAt(0))) {
+                    // Try the full part first
+                    var baseFqn = fqn.substring(0, i);
+                    try {
+                        return Class.forName(baseFqn);
+                    } catch (ClassNotFoundException _) {
+                    }
+
+                    // Try stripping capitalized segments from the end of the part
+                    // e.g., LabelAndDescriptionChoiceCom -> try LabelAndDescriptionChoice, then LabelAndDescription, etc.
+                    for (var j = fullPart.length() - 1; j > 0; j--) {
+                        if (Character.isUpperCase(fullPart.charAt(j))) {
+                            var strippedPart = fullPart.substring(0, j);
+                            var candidateFqn = fqn.substring(0, lastDotIndex + 1) + strippedPart;
+                            try {
+                                return Class.forName(candidateFqn);
+                            } catch (ClassNotFoundException _) {
+                            }
+                        }
+                    }
+                }
+                lastDotIndex = i;
+            }
         }
+        return null;
+    }
 
-        if (property.getItems() != null && property.getItems().get$ref() != null && property.getItems()
-                .get$ref()
-                .endsWith(NULLABLE_MARKER)) {
-            return true;
+    private static boolean isNullable(Class<?> cls, String propertyName) {
+        var currentClass = cls;
+        while (currentClass != null) {
+            try {
+                var field = currentClass.getDeclaredField(propertyName);
+                if (isNullable(field.getAnnotatedType(), field.getAnnotations())) {
+                    return true;
+                }
+            } catch (NoSuchFieldException _) {
+            }
+
+            for (var method : currentClass.getDeclaredMethods()) {
+                if (method.getName().equals(propertyName)
+                        || method.getName().equals("get" + capitalize(propertyName))
+                        || method.getName().equals("is" + capitalize(propertyName))) {
+                    if (isNullable(method.getAnnotatedReturnType(), method.getAnnotations())) {
+                        return true;
+                    }
+                }
+            }
+
+            currentClass = currentClass.getSuperclass();
         }
 
         return false;
     }
+
+    private static boolean isNullable(
+            AnnotatedType annotatedType,
+            Annotation[] annotations
+    ) {
+        if (annotatedType.isAnnotationPresent(org.jspecify.annotations.Nullable.class)) {
+            return true;
+        }
+        for (var annotation : annotations) {
+            var name = annotation.annotationType().getName();
+            if (name.equals("org.springframework.lang.Nullable") || name.equals("jakarta.annotation.Nullable")) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    private static String capitalize(String str) {
+        if (str.isEmpty()) {
+            return str;
+        }
+        return str.substring(0, 1).toUpperCase() + str.substring(1);
+    }
 }

src/test/java/it/aboutbits/springboot/toolbox/swagger/customization/default_not_null/NullableCustomizerTest.java

@@ -0,0 +1,158 @@
+package it.aboutbits.springboot.toolbox.swagger.customization.default_not_null;
+
+import io.swagger.v3.oas.models.Components;
+import io.swagger.v3.oas.models.OpenAPI;
+import io.swagger.v3.oas.models.media.Schema;
+import io.swagger.v3.oas.models.media.StringSchema;
+import org.jspecify.annotations.NullUnmarked;
+import org.jspecify.annotations.Nullable;
+import org.junit.jupiter.api.Test;
+
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@NullUnmarked
+class NullableCustomizerTest {
+
+    public static class BaseClass {
+        @Nullable
+        private String baseField;
+
+        public String getBaseField() {
+            return baseField;
+        }
+    }
+
+    public static class SubClass extends BaseClass {
+        private String subField;
+
+        public String getSubField() {
+            return subField;
+        }
+    }
+
+    public static class MethodAnnotated {
+        private String annotatedGetter;
+
+        @Nullable
+        public String getAnnotatedGetter() {
+            return annotatedGetter;
+        }
+    }
+
+    public static class DirectMethodAnnotated {
+        private String directMethod;
+
+        @Nullable
+        public String directMethod() {
+            return directMethod;
+        }
+    }
+
+    @Test
+    void shouldFindFieldInSuperClass() {
+        var customizer = new NullableCustomizer();
+        var openApi = new OpenAPI();
+        var components = new Components();
+
+        var subClassSchema = new Schema<Object>();
+        subClassSchema.setName(SubClass.class.getName());
+        subClassSchema.addProperty("baseField", new StringSchema());
+        subClassSchema.addProperty("subField", new StringSchema());
+
+        components.addSchemas(SubClass.class.getName(), subClassSchema);
+        openApi.setComponents(components);
+
+        assertDoesNotThrow(() -> customizer.customise(openApi));
+
+        List<String> required = subClassSchema.getRequired();
+        assertTrue(required != null && required.contains("subField"), "subField should be required");
+        assertTrue(required == null || !required.contains("baseField"), "baseField should NOT be required");
+    }
+
+    @Test
+    void shouldFindAnnotationOnGetter() {
+        var customizer = new NullableCustomizer();
+        var openApi = new OpenAPI();
+        var components = new Components();
+
+        var schema = new Schema<Object>();
+        schema.setName(MethodAnnotated.class.getName());
+        schema.addProperty("annotatedGetter", new StringSchema());
+
+        components.addSchemas(MethodAnnotated.class.getName(), schema);
+        openApi.setComponents(components);
+
+        assertDoesNotThrow(() -> customizer.customise(openApi));
+
+        List<String> required = schema.getRequired();
+        assertTrue(required == null || !required.contains("annotatedGetter"), "annotatedGetter should NOT be required");
+    }
+
+    @Test
+    void shouldFindAnnotationOnDirectMethod() {
+        var customizer = new NullableCustomizer();
+        var openApi = new OpenAPI();
+        var components = new Components();
+
+        var schema = new Schema<Object>();
+        schema.setName(DirectMethodAnnotated.class.getName());
+        schema.addProperty("directMethod", new StringSchema());
+
+        components.addSchemas(DirectMethodAnnotated.class.getName(), schema);
+        openApi.setComponents(components);
+
+        assertDoesNotThrow(() -> customizer.customise(openApi));
+
+        List<String> required = schema.getRequired();
+        assertTrue(required == null || !required.contains("directMethod"), "directMethod should NOT be required");
+    }
+
+    @Test
+    void shouldHandleConcatenatedFqns() {
+        var customizer = new NullableCustomizer();
+        var openApi = new OpenAPI();
+        var components = new Components();
+
+        var schema = new Schema<Object>();
+        // Simulating the concatenated FQN pattern described in the issue
+        var concatenatedFqn = SubClass.class.getName() + "It.aboutbits.something";
+        schema.setName(concatenatedFqn);
+        schema.addProperty("baseField", new StringSchema());
+
+        components.addSchemas(concatenatedFqn, schema);
+        openApi.setComponents(components);
+
+        assertDoesNotThrow(() -> customizer.customise(openApi));
+
+        List<String> required = schema.getRequired();
+        assertTrue(
+                required == null || !required.contains("baseField"),
+                "baseField should NOT be required even with concatenated FQN"
+        );
+    }
+
+    @Test
+    void shouldNotThrowWhenFieldNotFound() {
+        var customizer = new NullableCustomizer();
+        var openApi = new OpenAPI();
+        var components = new Components();
+
+        var schema = new Schema<Object>();
+        schema.setName(SubClass.class.getName());
+        schema.addProperty("nonExistent", new StringSchema());
+
+        components.addSchemas(SubClass.class.getName(), schema);
+        openApi.setComponents(components);
+
+        assertDoesNotThrow(() -> customizer.customise(openApi));
+
+        List<String> required = schema.getRequired();
+        assertTrue(
+                required != null && required.contains("nonExistent"),
+                "nonExistent field should be considered required if not found and not nullable"
+        );
+    }
+}