Fix oneOf interfaces for Java projects

modules/openapi-generator-cli/pom.xml

@@ -4,7 +4,7 @@
         <groupId>org.openapitools</groupId>
         <artifactId>openapi-generator-project</artifactId>
         <!-- RELEASE_VERSION -->
-        <version>5.0.0-SNAPSHOT</version>
+        <version>5.0.0-SYM</version>
         <!-- /RELEASE_VERSION -->
         <relativePath>../..</relativePath>
     </parent>

modules/openapi-generator-core/pom.xml

@@ -6,7 +6,7 @@
     <artifactId>openapi-generator-project</artifactId>
     <groupId>org.openapitools</groupId>
     <!-- RELEASE_VERSION -->
-    <version>5.0.0-SNAPSHOT</version>
+    <version>5.0.0-SYM</version>
     <!-- /RELEASE_VERSION -->
     <relativePath>../..</relativePath>
   </parent>

modules/openapi-generator-gradle-plugin/pom.xml

@@ -4,7 +4,7 @@
         <groupId>org.openapitools</groupId>
         <artifactId>openapi-generator-project</artifactId>
         <!-- RELEASE_VERSION -->
-        <version>5.0.0-SNAPSHOT</version>
+        <version>5.0.0-SYM</version>
         <!-- /RELEASE_VERSION -->
         <relativePath>../..</relativePath>
     </parent>

modules/openapi-generator-maven-plugin/pom.xml

@@ -5,7 +5,7 @@
         <groupId>org.openapitools</groupId>
         <artifactId>openapi-generator-project</artifactId>
         <!-- RELEASE_VERSION -->
-        <version>5.0.0-SNAPSHOT</version>
+        <version>5.0.0-SYM</version>
         <!-- /RELEASE_VERSION -->
         <relativePath>../..</relativePath>
     </parent>

modules/openapi-generator-online/pom.xml

@@ -4,7 +4,7 @@
         <groupId>org.openapitools</groupId>
         <artifactId>openapi-generator-project</artifactId>
         <!-- RELEASE_VERSION -->
-        <version>5.0.0-SNAPSHOT</version>
+        <version>5.0.0-SYM</version>
         <!-- /RELEASE_VERSION -->
         <relativePath>../..</relativePath>
     </parent>

modules/openapi-generator/pom.xml

@@ -4,7 +4,7 @@
         <groupId>org.openapitools</groupId>
         <artifactId>openapi-generator-project</artifactId>
         <!-- RELEASE_VERSION -->
-        <version>5.0.0-SNAPSHOT</version>
+        <version>5.0.0-SYM</version>
         <!-- /RELEASE_VERSION -->
         <relativePath>../..</relativePath>
     </parent>

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

@@ -804,26 +804,18 @@ public void preprocessOpenAPI(OpenAPI openAPI) {
 
             // go through all gathered schemas and add them as interfaces to be created
             for (Map.Entry<String, Schema> e : schemas.entrySet()) {
-                String n = toModelName(e.getKey());
-                Schema s = e.getValue();
-                String nOneOf = toModelName(n + "OneOf");
-                if (ModelUtils.isComposedSchema(s)) {
-                    if (e.getKey().contains("/")) {
-                        // if this is property schema, we also need to generate the oneOf interface model
-                        addOneOfNameExtension((ComposedSchema) s, nOneOf);
-                        addOneOfInterfaceModel((ComposedSchema) s, nOneOf, openAPI);
-                    } else {
-                        // else this is a component schema, so we will just use that as the oneOf interface model
-                        addOneOfNameExtension((ComposedSchema) s, n);
-                    }
-                } else if (ModelUtils.isArraySchema(s)) {
-                    Schema items = ((ArraySchema) s).getItems();
+              String modelName = toModelName(e.getKey());
+              Schema schema = e.getValue();
+              String nOneOf = toModelName(modelName + "OneOf");
+              if (ModelUtils.isComposedSchema(schema)) {
+                  addOneOfForComposedSchema(e, modelName, (ComposedSchema) schema, nOneOf, openAPI);
+              } else if (ModelUtils.isArraySchema(schema)) {
+                  Schema items = ((ArraySchema) schema).getItems();
                     if (ModelUtils.isComposedSchema(items)) {
-                        addOneOfNameExtension((ComposedSchema) items, nOneOf);
-                        addOneOfInterfaceModel((ComposedSchema) items, nOneOf, openAPI);
+                      addOneOfForComposedSchemaArray(nOneOf, modelName, (ComposedSchema) items, openAPI);
                     }
-                } else if (ModelUtils.isMapSchema(s)) {
-                    Schema addProps = getAdditionalProperties(s);
+                } else if (ModelUtils.isMapSchema(schema)) {
+                    Schema addProps = getAdditionalProperties(schema);
                     if (addProps != null && ModelUtils.isComposedSchema(addProps)) {
                         addOneOfNameExtension((ComposedSchema) addProps, nOneOf);
                         addOneOfInterfaceModel((ComposedSchema) addProps, nOneOf, openAPI);
@@ -833,6 +825,23 @@ public void preprocessOpenAPI(OpenAPI openAPI) {
         }
     }
 
+    protected void addOneOfForComposedSchemaArray(String nOneOf, String modelName, ComposedSchema items, OpenAPI openAPI) {
+        addOneOfNameExtension(items, nOneOf);
+        addOneOfInterfaceModel(items, nOneOf, openAPI);
+    }
+
+    protected void addOneOfForComposedSchema(Entry<String, Schema> stringSchemaEntry, String modelName, ComposedSchema composedSchema,
+        String nOneOf, OpenAPI openAPI) {
+        if (stringSchemaEntry.getKey().contains("/")) {
+            // if this is property schema, we also need to generate the oneOf interface model
+            addOneOfNameExtension(composedSchema, nOneOf);
+            addOneOfInterfaceModel(composedSchema, nOneOf, openAPI);
+        } else {
+            // else this is a component schema, so we will just use that as the oneOf interface model
+            addOneOfNameExtension(composedSchema, modelName);
+        }
+    }
+
     // override with any special handling of the entire OpenAPI spec document
     @SuppressWarnings("unused")
     public void processOpenAPI(OpenAPI openAPI) {
@@ -4610,13 +4619,13 @@ public void addOperationToGroup(String tag, String resourcePath, Operation opera
      * of the 'additionalProperties' keyword. Some language generator use class inheritance
      * to implement additional properties. For example, in Java the generated model class
      * has 'extends HashMap' to represent the additional properties.
-     * 
+     *
      * TODO: it's not a good idea to use single class inheritance to implement
      * additionalProperties. That may work for non-composed schemas, but that does not
      * work for composed 'allOf' schemas. For example, in Java, if additionalProperties
      * is set to true (which it should be by default, per OAS spec), then the generated
      * code has extends HashMap. That wouldn't work for composed 'allOf' schemas.
-     * 
+     *
      * @param model the codegen representation of the OAS schema.
      * @param name the name of the model.
      * @param schema the input OAS schema.
@@ -5847,7 +5856,7 @@ private void addBodyModelSchema(CodegenParameter codegenParameter, String name,
                                 "'application/x-www-form-urlencoded' or 'multipart/?'");
                         LOGGER.warn("schema: " + schema);
                         LOGGER.warn("codegenModel is null. Default to UNKNOWN_BASE_TYPE");
-                        codegenModelName = "UNKNOWN_BASE_TYPE";
+                        codegenModelName = getCodegenModelName(codegenProperty);
                         codegenModelDescription = "UNKNOWN_DESCRIPTION";
                     }
 
@@ -6062,6 +6071,10 @@ private void addJsonSchemaForBodyRequestInCaseItsNotPresent(CodegenParameter cod
             codegenParameter.jsonSchema = Json.pretty(body);
     }
 
+    protected String getCodegenModelName(CodegenProperty codegenProperty) {
+        return "UNKNOWN_BASE_TYPE";
+    }
+
     protected void addOption(String key, String description, String defaultValue) {
         CliOption option = new CliOption(key, description);
         if (defaultValue != null)
@@ -6471,15 +6484,15 @@ protected boolean isFreeFormObject(Schema schema) {
 
     /**
      * Returns the additionalProperties Schema for the specified input schema.
-     * 
+     *
      * The additionalProperties keyword is used to control the handling of additional, undeclared
      * properties, that is, properties whose names are not listed in the properties keyword.
      * The additionalProperties keyword may be either a boolean or an object.
      * If additionalProperties is a boolean and set to false, no additional properties are allowed.
      * By default when the additionalProperties keyword is not specified in the input schema,
      * any additional properties are allowed. This is equivalent to setting additionalProperties
      * to the boolean value True or setting additionalProperties: {}
-     * 
+     *
      * @param schema the input schema that may or may not have the additionalProperties keyword.
      * @return the Schema of the additionalProperties. The null value is returned if no additional
      *         properties are allowed.

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

@@ -61,6 +61,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
     public static final String BOOLEAN_GETTER_PREFIX = "booleanGetterPrefix";
     public static final String ADDITIONAL_MODEL_TYPE_ANNOTATIONS = "additionalModelTypeAnnotations";
     public static final String DISCRIMINATOR_CASE_SENSITIVE = "discriminatorCaseSensitive";
+    public static final String USE_ONEOF_INTERFACES = "useOneOfInterfaces";
 
     protected String dateLibrary = "threetenbp";
     protected boolean supportAsync = false;
@@ -197,6 +198,7 @@ public AbstractJavaCodegen() {
         cliOptions.add(CliOption.newBoolean(DISCRIMINATOR_CASE_SENSITIVE, "Whether the discriminator value lookup should be case-sensitive or not. This option only works for Java API client", discriminatorCaseSensitive));
         cliOptions.add(CliOption.newBoolean(CodegenConstants.HIDE_GENERATION_TIMESTAMP, CodegenConstants.HIDE_GENERATION_TIMESTAMP_DESC, this.isHideGenerationTimestamp()));
         cliOptions.add(CliOption.newBoolean(WITH_XML, "whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)"));
+        cliOptions.add(CliOption.newBoolean(USE_ONEOF_INTERFACES, "Generate interfaces for OneOf types"));
 
         CliOption dateLibrary = new CliOption(DATE_LIBRARY, "Option. Date library to use").defaultValue(this.getDateLibrary());
         Map<String, String> dateOptions = new HashMap<>();
@@ -540,6 +542,11 @@ public void processOpts() {
         } else if (dateLibrary.equals("legacy")) {
             additionalProperties.put("legacyDates", "true");
         }
+
+        if (additionalProperties.containsKey(USE_ONEOF_INTERFACES)) {
+            useOneOfInterfaces = Boolean.parseBoolean(additionalProperties.get(USE_ONEOF_INTERFACES).toString());
+            addOneOfInterfaceImports = useOneOfInterfaces;
+        }
     }
 
     @Override
@@ -1651,7 +1658,7 @@ public void setAdditionalModelTypeAnnotations(final List<String> additionalModel
     protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Schema schema) {
         if (!supportsAdditionalPropertiesWithComposedSchema) {
             // The additional (undeclared) propertiees are modeled in Java as a HashMap.
-            // 
+            //
             // 1. supportsAdditionalPropertiesWithComposedSchema is set to false:
             //    The generated model class extends from the HashMap. That does not work
             //    with composed schemas that also use a discriminator because the model class
@@ -1669,4 +1676,36 @@ protected void addAdditionPropertiesToCodeGenModel(CodegenModel codegenModel, Sc
             addImport(codegenModel, codegenModel.additionalPropertiesType);
         }
     }
+
+    @Override
+    protected String getCodegenModelName(CodegenProperty codegenProperty) {
+        return codegenProperty.getComplexType();
+    }
+
+    @Override
+    protected void addOneOfForComposedSchema(Map.Entry<String, Schema> stringSchemaEntry, String modelName,
+        ComposedSchema composedSchema, String nOneOf, OpenAPI openAPI) {
+        // if this is property schema, we also need to generate the oneOf interface model
+        addOneOfNameExtension(composedSchema, modelName);
+        addOneOfInterfaceModel(composedSchema, modelName, openAPI);
+    }
+
+    @Override
+    protected void addOneOfForComposedSchemaArray(String nOneOf, String modelName, ComposedSchema items, OpenAPI openAPI) {
+        addOneOfNameExtension(items, modelName);
+        addOneOfInterfaceModel(items, modelName, openAPI);
+    }
+
+    @Override
+    public void addImportsToOneOfInterface(List<Map<String, String>> imports) {
+        for (String i : Arrays.asList("JsonSubTypes", "JsonTypeInfo")) {
+            Map<String, String> oneImport = new HashMap<String, String>() {{
+                put("import", importMapping.get(i));
+            }};
+            if (!imports.contains(oneImport)) {
+                imports.add(oneImport);
+            }
+        }
+    }
+
 }

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/SpringCodegen.java

@@ -21,6 +21,8 @@
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.Operation;
 import io.swagger.v3.oas.models.PathItem;
+import io.swagger.v3.oas.models.media.ComposedSchema;
+import io.swagger.v3.oas.models.media.Schema;
 import org.apache.commons.lang3.tuple.Pair;
 import org.openapitools.codegen.*;
 import org.openapitools.codegen.languages.features.BeanValidationFeatures;

modules/openapi-generator/src/main/resources/JavaSpring/model.mustache

@@ -31,11 +31,6 @@ import org.springframework.hateoas.RepresentationModel;
 
 {{#models}}
 {{#model}}
-{{#isEnum}}
-{{>enumOuterClass}}
-{{/isEnum}}
-{{^isEnum}}
-{{>pojo}}
-{{/isEnum}}
+{{#isEnum}}{{>enumOuterClass}}{{/isEnum}}{{^isEnum}}{{#vendorExtensions.x-is-one-of-interface}}{{>oneof_interface}}{{/vendorExtensions.x-is-one-of-interface}}{{^vendorExtensions.x-is-one-of-interface}}{{>pojo}}{{/vendorExtensions.x-is-one-of-interface}}{{/isEnum}}
 {{/model}}
 {{/models}}

modules/openapi-generator/src/main/resources/JavaSpring/oneof_interface.mustache

@@ -0,0 +1,6 @@
+{{>additionalModelTypeAnnotations}}{{>generatedAnnotation}}{{>typeInfoAnnotation}}{{>xmlAnnotation}}
+public interface {{classname}} {{#vendorExtensions.x-implements}}{{#-first}}extends {{{.}}}{{/-first}}{{^-first}}, {{{.}}}{{/-first}}{{/vendorExtensions.x-implements}} {
+{{#discriminator}}
+  public {{propertyType}} {{propertyGetter}}();
+{{/discriminator}}
+}

modules/openapi-generator/src/main/resources/JavaSpring/pojo.mustache

@@ -3,7 +3,7 @@
  */{{#description}}
 @ApiModel(description = "{{{description}}}"){{/description}}
 {{>generatedAnnotation}}{{#discriminator}}{{>typeInfoAnnotation}}{{/discriminator}}{{>xmlAnnotation}}{{>additionalModelTypeAnnotations}}
-public class {{classname}} {{#parent}}extends {{{parent}}}{{/parent}}{{^parent}}{{#hateoas}}extends RepresentationModel<{{classname}}> {{/hateoas}}{{/parent}} {{#serializableModel}}implements Serializable{{/serializableModel}} {
+public class {{classname}}{{#parent}} extends {{{parent}}}{{/parent}}{{^parent}}{{#hateoas}} extends RepresentationModel<{{classname}}>{{/hateoas}}{{/parent}}{{#vendorExtensions.x-implements}}{{#-first}} implements {{{.}}}{{/-first}}{{^-first}}, {{{.}}}{{/-first}}{{#-last}} {{/-last}}{{/vendorExtensions.x-implements}}{{^vendorExtensions.x-implements}}{{#serializableModel}} implements Serializable{{/serializableModel}}{{/vendorExtensions.x-implements}} {
 {{#serializableModel}}
   private static final long serialVersionUID = 1L;
 
@@ -14,7 +14,7 @@ public class {{classname}} {{#parent}}extends {{{parent}}}{{/parent}}{{^parent}}
 {{>enumClass}}
     {{/isContainer}}
     {{#isContainer}}
-    {{#mostInnerItems}} 
+    {{#mostInnerItems}}
 {{>enumClass}}
     {{/mostInnerItems}}
     {{/isContainer}}

pom.xml

@@ -10,7 +10,7 @@
     <packaging>pom</packaging>
     <name>openapi-generator-project</name>
     <!-- RELEASE_VERSION -->
-    <version>5.0.0-SNAPSHOT</version>
+    <version>5.0.0-SYM</version>
     <!-- /RELEASE_VERSION -->
     <url>https://github.com/openapitools/openapi-generator</url>
     <scm>