diff --git a/docs/customization.md b/docs/customization.md
index c63f71472ce0a44f0944384822876709932aa7b9..1e21e9494f262a867defe082c3b8589122b9dce2 100644
--- a/docs/customization.md
+++ b/docs/customization.md
@@ -484,3 +484,10 @@ Example:
```
java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/simplifyBooleanEnum_test.yaml -o /tmp/java-okhttp/ --openapi-normalizer SIMPLIFY_BOOLEAN_ENUM=true
```
+
+- `SIMPLIFY_ONEOF_ANYOF`: when set to `true`, simplify oneOf/anyOf by 1) removing null (sub-schema) and setting nullable to true instead, and 2) simplifying oneOf/anyOf with a single sub-schema to just the sub-schema itself.
+
+Example:
+```
+java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/3_0/simplifyOneOfAnyOf_test.yaml -o /tmp/java-okhttp/ --openapi-normalizer SIMPLIFY_ONEOF_ANYOF=true
+```
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java
index 639e1bdac2d92b3984438885754eac29cedda8a7..9a2dbd17bb5c463e8fecf7079d631fab2c2555ff 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/OpenAPINormalizer.java
@@ -63,6 +63,11 @@ public class OpenAPINormalizer {
final String SIMPLIFY_ANYOF_STRING_AND_ENUM_STRING = "SIMPLIFY_ANYOF_STRING_AND_ENUM_STRING";
boolean simplifyAnyOfStringAndEnumString;
+ // when set to true, oneOf/anyOf schema with only one sub-schema is simplified to just the sub-schema
+ // and if sub-schema contains "null", remove it and set nullable to true instead
+ final String SIMPLIFY_ONEOF_ANYOF = "SIMPLIFY_ONEOF_ANYOF";
+ boolean simplifyOneOfAnyOf;
+
// when set to true, boolean enum will be converted to just boolean
final String SIMPLIFY_BOOLEAN_ENUM = "SIMPLIFY_BOOLEAN_ENUM";
boolean simplifyBooleanEnum;
@@ -111,6 +116,10 @@ public class OpenAPINormalizer {
simplifyAnyOfStringAndEnumString = true;
}
+ if (enableAll || "true".equalsIgnoreCase(rules.get(SIMPLIFY_ONEOF_ANYOF))) {
+ simplifyOneOfAnyOf = true;
+ }
+
if (enableAll || "true".equalsIgnoreCase(rules.get(SIMPLIFY_BOOLEAN_ENUM))) {
simplifyBooleanEnum = true;
}
@@ -390,27 +399,36 @@ public class OpenAPINormalizer {
private Schema normalizeOneOf(Schema schema, Set<Schema> visitedSchemas) {
for (Object item : schema.getOneOf()) {
+ if (item == null) {
+ continue;
+ }
if (!(item instanceof Schema)) {
- throw new RuntimeException("Error! allOf schema is not of the type Schema: " + item);
+ throw new RuntimeException("Error! oneOf schema is not of the type Schema: " + item);
}
// normalize oenOf sub schemas one by one
normalizeSchema((Schema) item, visitedSchemas);
}
-
// process rules here
+ schema = processSimplifyOneOf(schema);
+
return schema;
}
private Schema normalizeAnyOf(Schema schema, Set<Schema> visitedSchemas) {
for (Object item : schema.getAnyOf()) {
+ if (item == null) {
+ continue;
+ }
+
if (!(item instanceof Schema)) {
- throw new RuntimeException("Error! allOf schema is not of the type Schema: " + item);
+ throw new RuntimeException("Error! anyOf schema is not of the type Schema: " + item);
}
// normalize anyOf sub schemas one by one
normalizeSchema((Schema) item, visitedSchemas);
}
// process rules here
+ schema = processSimplifyAnyOf(schema);
// last rule to process as the schema may become String schema (not "anyOf") after the completion
return processSimplifyAnyOfStringAndEnumString(schema);
@@ -506,7 +524,7 @@ public class OpenAPINormalizer {
/**
* If the schema is anyOf and the sub-schemas are either string or enum of string,
- * then simply it to just string as many generators do not yet support anyOf.
+ * then simplify it to just string as many generators do not yet support anyOf.
*
* @param schema Schema
* @return Schema
@@ -541,6 +559,72 @@ public class OpenAPINormalizer {
}
}
+ /**
+ * If the schema is oneOf and the sub-schemas is null, set `nullable: true` instead.
+ * If there's only one sub-schema, simply return the sub-schema directly.
+ *
+ * @param schema Schema
+ * @return Schema
+ */
+ private Schema processSimplifyOneOf(Schema schema) {
+ if (!simplifyOneOfAnyOf && !enableAll) {
+ return schema;
+ }
+
+ if (schema.getOneOf() != null && !schema.getOneOf().isEmpty()) {
+ // convert null sub-schema to `nullable: true`
+ for (int i = 0; i < schema.getOneOf().size(); i++) {
+ if (schema.getOneOf().get(i) == null || ((Schema) schema.getOneOf().get(i)).getType() == null) {
+ schema.getOneOf().remove(i);
+ schema.setNullable(true);
+ }
+ }
+
+ // if only one element left, simplify to just the element (schema)
+ if (schema.getOneOf().size() == 1) {
+ if (schema.getNullable()) { // retain nullable setting
+ ((Schema) schema.getOneOf().get(0)).setNullable(true);
+ }
+ return (Schema) schema.getOneOf().get(0);
+ }
+ }
+
+ return schema;
+ }
+
+ /**
+ * If the schema is anyOf and the sub-schemas is null, set `nullable: true` instead.
+ * If there's only one sub-schema, simply return the sub-schema directly.
+ *
+ * @param schema Schema
+ * @return Schema
+ */
+ private Schema processSimplifyAnyOf(Schema schema) {
+ if (!simplifyOneOfAnyOf && !enableAll) {
+ return schema;
+ }
+
+ if (schema.getAnyOf() != null && !schema.getAnyOf().isEmpty()) {
+ // convert null sub-schema to `nullable: true`
+ for (int i = 0; i < schema.getAnyOf().size(); i++) {
+ if (schema.getAnyOf().get(i) == null || ((Schema) schema.getAnyOf().get(i)).getType() == null) {
+ schema.getAnyOf().remove(i);
+ schema.setNullable(true);
+ }
+ }
+
+ // if only one element left, simplify to just the element (schema)
+ if (schema.getAnyOf().size() == 1) {
+ if (schema.getNullable()) { // retain nullable setting
+ ((Schema) schema.getAnyOf().get(0)).setNullable(true);
+ }
+ return (Schema) schema.getAnyOf().get(0);
+ }
+ }
+
+ return schema;
+ }
+
/**
* If the schema is boolean and its enum is defined,
* then simply it to just boolean.
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
index 103c8a05cb7174837fd9eb80a1febfc2d32ae3bc..b656e8c1c91febeae4cb1bb8e936a87270ff30a8 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
@@ -4395,6 +4395,42 @@ public class DefaultCodegenTest {
assertTrue(schema3 instanceof StringSchema);
}
+ @Test
+ public void testOpenAPINormalizerSimplifyOneOfAnyOf() {
+ // to test the rule SIMPLIFY_ONEOF_ANYOF
+ OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/simplifyOneOfAnyOf_test.yaml");
+
+ Schema schema = openAPI.getComponents().getSchemas().get("AnyOfTest");
+ assertEquals(schema.getAnyOf().size(), 2);
+ assertNull(schema.getNullable());
+
+ Schema schema2 = openAPI.getComponents().getSchemas().get("OneOfTest");
+ assertEquals(schema2.getOneOf().size(), 2);
+ assertNull(schema2.getNullable());
+
+ Schema schema5 = openAPI.getComponents().getSchemas().get("OneOfNullableTest");
+ assertEquals(schema5.getOneOf().size(), 3);
+ assertNull(schema5.getNullable());
+
+ Map<String, String> options = new HashMap<>();
+ options.put("SIMPLIFY_ONEOF_ANYOF", "true");
+ OpenAPINormalizer openAPINormalizer = new OpenAPINormalizer(openAPI, options);
+ openAPINormalizer.normalize();
+
+ Schema schema3 = openAPI.getComponents().getSchemas().get("AnyOfTest");
+ assertNull(schema3.getAnyOf());
+ assertTrue(schema3 instanceof StringSchema);
+ assertTrue(schema3.getNullable());
+
+ Schema schema4 = openAPI.getComponents().getSchemas().get("OneOfTest");
+ assertNull(schema4.getOneOf());
+ assertTrue(schema4 instanceof IntegerSchema);
+
+ Schema schema6 = openAPI.getComponents().getSchemas().get("OneOfNullableTest");
+ assertEquals(schema6.getOneOf().size(), 2);
+ assertTrue(schema6.getNullable());
+ }
+
@Test
public void testOpenAPINormalizerSimplifyBooleanEnum() {
// to test the rule SIMPLIFY_BOOLEAN_ENUM
diff --git a/modules/openapi-generator/src/test/resources/3_0/simplifyOneOfAnyOf_test.yaml b/modules/openapi-generator/src/test/resources/3_0/simplifyOneOfAnyOf_test.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..5f0cf2370de7f4e95066505f6201ee8dba6349f8
--- /dev/null
+++ b/modules/openapi-generator/src/test/resources/3_0/simplifyOneOfAnyOf_test.yaml
@@ -0,0 +1,45 @@
+openapi: 3.0.1
+info:
+ version: 1.0.0
+ title: Example
+ license:
+ name: MIT
+servers:
+ - url: http://api.example.xyz/v1
+paths:
+ /person/display/{personId}:
+ get:
+ parameters:
+ - name: personId
+ in: path
+ required: true
+ description: The id of the person to retrieve
+ schema:
+ type: string
+ operationId: list
+ responses:
+ '200':
+ description: OK
+ content:
+ application/json:
+ schema:
+ $ref: "#/components/schemas/AnyOfTest"
+components:
+ schemas:
+ AnyOfTest:
+ description: to test anyOf
+ anyOf:
+ - type: string
+ - type: null
+ OneOfTest:
+ description: to test oneOf
+ oneOf:
+ - type: integer
+ - $ref: null
+ OneOfNullableTest:
+ description: to test oneOf nullable
+ oneOf:
+ - type: integer
+ - type: string
+ - $ref: null
+