Add primitive types support to ExampleGenerator

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

@@ -75,8 +75,7 @@ private List<Map<String, String>> generateFromResponseSchema(Schema responseSche
         }
 
         if (responseSchema.getExample() != null && !(responseSchema.getExample() instanceof Map)) {
-            LOGGER.warn("example value (array/primitive) not handled at the moment: " + responseSchema.getExample());
-            return null;
+            return generate(responseSchema.getExample(), new ArrayList<>(producesInfo));
         }
 
         if (ModelUtils.isArraySchema(responseSchema)) { // array of schema
@@ -190,6 +189,34 @@ public List<Map<String, String>> generate(Map<String, Object> examples, List<Str
         return output;
     }
 
+    private List<Map<String, String>> generate(Object example, List<String> mediaTypes) {
+        List<Map<String, String>> output = new ArrayList<>();
+        if (examples != null) {
+            if (mediaTypes == null) {
+                // assume application/json for this
+                mediaTypes = Collections.singletonList(MIME_TYPE_JSON);
+            }
+            for (String mediaType : mediaTypes) {
+                Map<String, String> kv = new HashMap<>();
+                kv.put(CONTENT_TYPE, mediaType);
+                if ((mediaType.startsWith(MIME_TYPE_JSON) || mediaType.contains("*/*"))) {
+                    kv.put(EXAMPLE, Json.pretty(example));
+                    output.add(kv);
+                } else if (mediaType.startsWith(MIME_TYPE_XML)) {
+                    // TODO
+                    LOGGER.warn("XML example value of (array/primitive) is not handled at the moment: " + example);
+                }
+            }
+        }
+
+        if (output.size() == 0) {
+            Map<String, String> kv = new HashMap<>();
+            kv.put(OUTPUT, NONE);
+            output.add(kv);
+        }
+        return output;
+    }
+
     private Object resolvePropertyToExample(String propertyName, String mediaType, Schema property, Set<String> processedModels) {
         LOGGER.debug("Resolving example for property {}...", property);
         if (property.getExample() != null) {

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

@@ -11,6 +11,36 @@
 import static org.testng.AssertJUnit.*;
 
 public class ExampleGeneratorTest {
+    @Test
+    public void generateFromResponseSchemaWithPrimitiveType() {
+        OpenAPI openAPI = new OpenAPIParser().readLocation("src/test/resources/3_0/example_generator_test.yaml", null, new
+                ParseOptions()).getOpenAPI();
+
+        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_primitive_type")
+                        .getGet()
+                        .getResponses()
+                        .get("200")
+                        .getContent()
+                        .get("application/json")
+                        .getSchema(),
+                mediaTypeKeys
+        );
+
+        assertEquals(1, examples.size());
+        assertEquals("application/json", examples.get(0).get("contentType"));
+        assertEquals("\"primitive type example value\"", examples.get(0).get("example"));
+        assertEquals("200", examples.get(0).get("statusCode"));
+    }
+
     @Test
     public void generateFromResponseSchemaWithNoExample() {
         OpenAPI openAPI = new OpenAPIParser().readLocation("src/test/resources/3_0/example_generator_test.yaml", null, new

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

@@ -15,6 +15,17 @@ paths:
             application/json:
               schema:
                 type: string
+  /generate_from_response_schema_with_primitive_type:
+    get:
+      operationId: generateFromResponseSchemaWithNoExample
+      responses:
+        '200':
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                type: string
+                example: primitive type example value
   /generate_from_response_schema_with_array_of_model:
     get:
       operationId: generateFromResponseSchemaWithArrayOfModel