fix: ExampleGenerator correctly generates allOf composed schemas

modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/ExampleGenerator.java

@@ -351,15 +351,57 @@ private Object resolveModelToExample(String name, String mediaType, Schema schem
             return schema.getExample();
         } else if (schema.getProperties() != null) {
             LOGGER.debug("Creating example from model values");
-            for (Object propertyName : schema.getProperties().keySet()) {
-                Schema property = (Schema) schema.getProperties().get(propertyName.toString());
-                values.put(propertyName.toString(), resolvePropertyToExample(propertyName.toString(), mediaType, property, processedModels));
+            traverseSchemaProperties(mediaType, schema, processedModels, values);
+            schema.setExample(values);
+            return schema.getExample();
+        } else if (ModelUtils.isAllOf(schema) || ModelUtils.isAllOfWithProperties(schema)) {
+            LOGGER.debug("Resolving allOf model '{}' to example", name);
+            List<Schema> interfaces = schema.getAllOf();
+            for (Schema composed : interfaces) {
+                traverseSchemaProperties(mediaType, composed, processedModels, values);
+                if (composed.get$ref() != null) {
+                    String ref = ModelUtils.getSimpleRef(composed.get$ref());
+                    Schema resolved = ModelUtils.getSchema(openAPI, ref);
+                    if (resolved != null) {
+                        traverseSchemaProperties(mediaType, resolved, processedModels, values);
+                    }
+                }
             }
             schema.setExample(values);
             return schema.getExample();
+        } else if (ModelUtils.isAnyOf(schema) || ModelUtils.isOneOf(schema)) {
+            LOGGER.debug("Resolving anyOf/oneOf model '{}' using the first schema to example", name);
+            Optional<Schema> found = ModelUtils.getInterfaces(schema)
+                    .stream()
+                    .filter(this::hasValidRef)
+                    .findFirst();
+
+            if (found.isEmpty()) {
+                return null;
+            }
+            return resolvePropertyToExample(name, mediaType, found.get(), processedModels);
         } else {
             // TODO log an error message as the model does not have any properties
             return null;
         }
     }
+
+    private void traverseSchemaProperties(String mediaType, Schema schema, Set<String> processedModels, Map<String, Object> values) {
+        if (schema.getProperties() != null) {
+            for (Object propertyName : schema.getProperties().keySet()) {
+                Schema property = (Schema) schema.getProperties().get(propertyName.toString());
+                values.put(propertyName.toString(), resolvePropertyToExample(propertyName.toString(), mediaType, property, processedModels));
+            }
+        }
+    }
+
+    private boolean hasValidRef(Schema schema) {
+        if (schema.get$ref() != null) {
+            String ref = ModelUtils.getSimpleRef(schema.get$ref());
+            Schema resolved = ModelUtils.getSchema(openAPI, ref);
+            return resolved != null;
+        }
+
+        return true;
+    }
 }

modules/openapi-generator/src/test/java/org/openapitools/codegen/ExampleGeneratorTest.java

@@ -151,4 +151,91 @@ public void generateFromResponseSchemaWithModel() {
         assertEquals(String.format(Locale.ROOT, "{%n  \"example_schema_property\" : \"example schema property value\"%n}"), examples.get(0).get("example"));
         assertEquals("200", examples.get(0).get("statusCode"));
     }
+
+    @Test
+    public void generateFromResponseSchemaWithAllOfComposedModel() {
+        OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/example_generator_test.yaml");
+
+        new InlineModelResolver().flatten(openAPI);
+
+        ExampleGenerator exampleGenerator = new ExampleGenerator(openAPI.getComponents().getSchemas(), openAPI);
+        Set<String> mediaTypeKeys = new TreeSet<>();
+        mediaTypeKeys.add("application/json");
+        List<Map<String, String>> examples = exampleGenerator.generateFromResponseSchema(
+                "200",
+                openAPI
+                        .getPaths()
+                        .get("/generate_from_response_schema_with_allOf_composed_model")
+                        .getGet()
+                        .getResponses()
+                        .get("200")
+                        .getContent()
+                        .get("application/json")
+                        .getSchema(),
+                mediaTypeKeys
+        );
+
+        assertEquals(1, examples.size());
+        assertEquals("application/json", examples.get(0).get("contentType"));
+        assertEquals(String.format(Locale.ROOT, "{%n  \"example_schema_property_composed\" : \"example schema property value composed\",%n  \"example_schema_property\" : \"example schema property value\"%n}"), examples.get(0).get("example"));
+        assertEquals("200", examples.get(0).get("statusCode"));
+    }
+
+    @Test
+    public void generateFromResponseSchemaWithOneOfComposedModel() {
+        OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/example_generator_test.yaml");
+
+        new InlineModelResolver().flatten(openAPI);
+
+        ExampleGenerator exampleGenerator = new ExampleGenerator(openAPI.getComponents().getSchemas(), openAPI);
+        Set<String> mediaTypeKeys = new TreeSet<>();
+        mediaTypeKeys.add("application/json");
+        List<Map<String, String>> examples = exampleGenerator.generateFromResponseSchema(
+                "200",
+                openAPI
+                        .getPaths()
+                        .get("/generate_from_response_schema_with_oneOf_composed_model")
+                        .getGet()
+                        .getResponses()
+                        .get("200")
+                        .getContent()
+                        .get("application/json")
+                        .getSchema(),
+                mediaTypeKeys
+        );
+
+        assertEquals(1, examples.size());
+        assertEquals("application/json", examples.get(0).get("contentType"));
+        assertEquals(String.format(Locale.ROOT, "{%n  \"example_schema_property\" : \"example schema property value\"%n}"), examples.get(0).get("example"));
+        assertEquals("200", examples.get(0).get("statusCode"));
+    }
+
+    @Test
+    public void generateFromResponseSchemaWithAnyOfComposedModel() {
+        OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/example_generator_test.yaml");
+
+        new InlineModelResolver().flatten(openAPI);
+
+        ExampleGenerator exampleGenerator = new ExampleGenerator(openAPI.getComponents().getSchemas(), openAPI);
+        Set<String> mediaTypeKeys = new TreeSet<>();
+        mediaTypeKeys.add("application/json");
+        List<Map<String, String>> examples = exampleGenerator.generateFromResponseSchema(
+                "200",
+                openAPI
+                        .getPaths()
+                        .get("/generate_from_response_schema_with_anyOf_composed_model")
+                        .getGet()
+                        .getResponses()
+                        .get("200")
+                        .getContent()
+                        .get("application/json")
+                        .getSchema(),
+                mediaTypeKeys
+        );
+
+        assertEquals(1, examples.size());
+        assertEquals("application/json", examples.get(0).get("contentType"));
+        assertEquals(String.format(Locale.ROOT, "{%n  \"example_schema_property\" : \"example schema property value\"%n}"), examples.get(0).get("example"));
+        assertEquals("200", examples.get(0).get("statusCode"));
+    }
 }

modules/openapi-generator/src/test/resources/3_0/example_generator_test.yaml

@@ -53,14 +53,44 @@ paths:
                   example: primitive types example value
   /generate_from_response_schema_with_model:
     get:
-      operationId: generateFromResponseSchemaWithArrayOfPrimitiveTypes
+      operationId: generateFromResponseSchemaWithModel
       responses:
         '200':
           description: successful operation
           content:
             application/json:
               schema:
                 $ref: '#/components/schemas/ExampleSchema'
+  /generate_from_response_schema_with_allOf_composed_model:
+    get:
+      operationId: generateFromResponseSchemaWithAllOfModel
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ExampleAllOfSchema'
+  /generate_from_response_schema_with_anyOf_composed_model:
+    get:
+      operationId: generateFromResponseSchemaWithAnyOfModel
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ExampleAnyOfSchema'
+  /generate_from_response_schema_with_oneOf_composed_model:
+    get:
+      operationId: generateFromResponseSchemaWithOneOfModel
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/ExampleOneOfSchema'
 components:
   schemas:
     StringSchema:
@@ -72,3 +102,30 @@ components:
         example_schema_property:
           type: string
           example: example schema property value
+    ExampleAllOfSchema:
+      type: object
+      allOf:
+        - $ref: '#/components/schemas/ExampleSchema'
+        - type: object
+          properties:
+            example_schema_property_composed:
+              type: string
+              example: example schema property value composed
+    ExampleAnyOfSchema:
+      type: object
+      anyOf:
+        - $ref: '#/components/schemas/ExampleSchema'
+        - type: object
+          properties:
+            example_schema_property_composed:
+              type: string
+              example: example schema property value composed
+    ExampleOneOfSchema:
+      type: object
+      oneOf:
+        - $ref: '#/components/schemas/ExampleSchema'
+        - type: object
+          properties:
+            example_schema_property_composed:
+              type: string
+              example: example schema property value composed

samples/client/petstore/java/apache-httpclient/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/feign/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/okhttp-gson/api/openapi.yaml

@@ -2411,7 +2411,7 @@ components:
       description: Value object
       example:
         name: variable_1
-        value: null
+        value: Scalar
       properties:
         name:
           example: variable_1

samples/client/petstore/java/resteasy/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/resttemplate-withXml/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/resttemplate/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/vertx/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/webclient-jakarta/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/webclient-swagger2/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/client/petstore/java/webclient/api/openapi.yaml

@@ -1942,6 +1942,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean

samples/openapi3/client/petstore/java/jersey2-java8-special-characters/api/openapi.yaml

@@ -49,4 +49,7 @@ components:
         \ characters. The sanitization rules should make it possible to generate a\
         \ language-specific classname with allowed characters in that programming\
         \ language."
+      example:
+        prop2: prop2
+        objectType: objectType
 

samples/openapi3/server/petstore/spring-boot-oneof/src/main/java/org/openapitools/api/BarApi.java

@@ -71,7 +71,7 @@ default ResponseEntity<Bar> createBar(
         getRequest().ifPresent(request -> {
             for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
                 if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
-                    String exampleString = "{ \"id\" : \"id\", \"fooPropB\" : \"fooPropB\", \"barPropA\" : \"barPropA\" }";
+                    String exampleString = "{ \"foo\" : { \"fooPropA\" : \"fooPropA\", \"fooPropB\" : \"fooPropB\" }, \"id\" : \"id\", \"fooPropB\" : \"fooPropB\", \"barPropA\" : \"barPropA\" }";
                     ApiUtil.setExampleResponse(request, "application/json", exampleString);
                     break;
                 }

samples/openapi3/server/petstore/spring-boot-oneof/src/main/java/org/openapitools/api/FooApi.java

@@ -71,7 +71,7 @@ default ResponseEntity<FooRefOrValue> createFoo(
         getRequest().ifPresent(request -> {
             for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
                 if (mediaType.isCompatibleWith(MediaType.valueOf("application/json"))) {
-                    String exampleString = "null";
+                    String exampleString = "{ \"fooPropA\" : \"fooPropA\", \"fooPropB\" : \"fooPropB\" }";
                     ApiUtil.setExampleResponse(request, "application/json", exampleString);
                     break;
                 }
@@ -109,7 +109,7 @@ default ResponseEntity<List<FooRefOrValue>> getAllFoos(
         getRequest().ifPresent(request -> {
             for (MediaType mediaType: MediaType.parseMediaTypes(request.getHeader("Accept"))) {
                 if (mediaType.isCompatibleWith(MediaType.valueOf("application/json;charset=utf-8"))) {
-                    String exampleString = "[ null, null ]";
+                    String exampleString = "[ { \"fooPropA\" : \"fooPropA\", \"fooPropB\" : \"fooPropB\" }, { \"fooPropA\" : \"fooPropA\", \"fooPropB\" : \"fooPropB\" } ]";
                     ApiUtil.setExampleResponse(request, "application/json;charset=utf-8", exampleString);
                     break;
                 }

samples/openapi3/server/petstore/spring-boot-oneof/src/main/resources/openapi.yaml

@@ -189,7 +189,9 @@ components:
       allOf:
       - $ref: '#/components/schemas/Entity'
       example:
-        foo: null
+        foo:
+          fooPropA: fooPropA
+          fooPropB: fooPropB
         id: id
         fooPropB: fooPropB
         barPropA: barPropA

samples/openapi3/server/petstore/springboot-delegate/src/main/resources/openapi.yaml

@@ -1902,6 +1902,10 @@ components:
           otherProperty:
             type: string
         type: object
+      example:
+        otherProperty: otherProperty
+        nullableProperty: nullableProperty
+        type: ChildWithNullable
     StringBooleanMap:
       additionalProperties:
         type: boolean