Add an option to generate the alias (map, array) as model

modules/openapi-generator-cli/src/main/java/org/openapitools/codegen/cmd/Generate.java

@@ -208,6 +208,9 @@ public class Generate implements Runnable {
     @Option(name = {"--enable-post-process-file"}, title = "enable post-process file", description = CodegenConstants.ENABLE_POST_PROCESS_FILE)
     private Boolean enablePostProcessFile;
 
+    @Option(name = {"--generate-alias-as-model"}, title = "generate alias (array, map) as model", description = CodegenConstants.GENERATE_ALIAS_AS_MODEL_DESC)
+    private Boolean generateAliasAsModel;
+
     @Override
     public void run() {
         if (logToStderr != null) {
@@ -334,6 +337,10 @@ public void run() {
             configurator.setEnablePostProcessFile(enablePostProcessFile);
         }
 
+        if (generateAliasAsModel != null) {
+            configurator.setGenerateAliasAsModel(generateAliasAsModel);
+        }
+
         applySystemPropertiesKvpList(systemProperties, configurator);
         applyInstantiationTypesKvpList(instantiationTypes, configurator);
         applyImportMappingsKvpList(importMappings, configurator);

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

@@ -262,11 +262,11 @@ public interface CodegenConfig {
 
     boolean isEnablePostProcessFile();
 
-    public void setEnablePostProcessFile(boolean isEnablePostProcessFile);
+    void setEnablePostProcessFile(boolean isEnablePostProcessFile);
 
     // set OpenAPI and schemas
-    public void setGlobalOpenAPI(OpenAPI openAPI);
+    void setGlobalOpenAPI(OpenAPI openAPI);
 
-    public void setGlobalSchemas(OpenAPI openAPI);
+    void setGlobalSchemas(OpenAPI openAPI);
 
 }

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

@@ -283,4 +283,7 @@ public static enum ENUM_PROPERTY_NAMING_TYPE {camelCase, PascalCase, snake_case,
     public static final String ENABLE_POST_PROCESS_FILE_DESC = "Enable post-processing file using environment variables.";
 
     public static final String OPEN_API_SPEC_NAME = "openAPISpecName";
+
+    public static final String GENERATE_ALIAS_AS_MODEL = "generateAliasAsModel";
+    public static final String GENERATE_ALIAS_AS_MODEL_DESC = "Generate alias to map, array as models";
 }

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

@@ -209,6 +209,11 @@ public void processOpts() {
             this.setEnablePostProcessFile(Boolean.valueOf(additionalProperties
                     .get(CodegenConstants.ENABLE_POST_PROCESS_FILE).toString()));
         }
+
+        if (additionalProperties.containsKey(CodegenConstants.GENERATE_ALIAS_AS_MODEL)) {
+            ModelUtils.setGenerateAliasAsModel(Boolean.valueOf(additionalProperties
+                    .get(CodegenConstants.GENERATE_ALIAS_AS_MODEL).toString()));
+        }
     }
 
     // override with any special post-processing for all models

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

@@ -432,7 +432,7 @@ private Model getParent(Model model) {
 
                 // check to see if it's a "map" model
                 if (ModelUtils.isMapSchema(schema)) {
-                    if (schema.getProperties() == null || schema.getProperties().isEmpty()) {
+                    if (!ModelUtils.isGenerateAliasAsModel() && (schema.getProperties() == null || schema.getProperties().isEmpty())) {
                         // schema without property, i.e. alias to map
                         LOGGER.info("Model " + name + " not generated since it's an alias to map (without property)");
                         continue;
@@ -441,7 +441,7 @@ private Model getParent(Model model) {
 
                 // check to see if it's an "array" model
                 if (ModelUtils.isArraySchema(schema)) {
-                    if (schema.getProperties() == null || schema.getProperties().isEmpty()) {
+                    if (!ModelUtils.isGenerateAliasAsModel() && (schema.getProperties() == null || schema.getProperties().isEmpty())) {
                         // schema without property, i.e. alias to array
                         LOGGER.info("Model " + name + " not generated since it's an alias to array (without property)");
                         continue;

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

@@ -220,6 +220,15 @@ public CodegenConfigurator setEnablePostProcessFile(boolean enablePostProcessFil
         return this;
     }
 
+    public boolean isGenerateAliasAsModel() {
+        return ModelUtils.isGenerateAliasAsModel();
+    }
+
+    public CodegenConfigurator setGenerateAliasAsModel(boolean generateAliasAsModel) {
+        ModelUtils.setGenerateAliasAsModel(generateAliasAsModel);
+        return this;
+    }
+
     public String getModelNameSuffix() {
         return modelNameSuffix;
     }

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

@@ -61,6 +61,16 @@
 
 public class ModelUtils {
     private static final Logger LOGGER = LoggerFactory.getLogger(ModelUtils.class);
+    private static boolean generateAliasAsModel = false;
+
+    public static void setGenerateAliasAsModel(boolean value) {
+        generateAliasAsModel = value;
+    }
+
+    public static boolean isGenerateAliasAsModel() {
+        return generateAliasAsModel;
+    }
+
 
     /**
      * Searches for the model by name in the map of models and returns it
@@ -769,15 +779,23 @@ public static Schema unaliasSchema(Map<String, Schema> allSchemas, Schema schema
                 // top-level enum class
                 return schema;
             } else if (isArraySchema(ref)) {
-                return unaliasSchema(allSchemas, allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())));
+                if (generateAliasAsModel) {
+                    return schema; // generate a model extending array
+                } else {
+                    return unaliasSchema(allSchemas, allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())));
+                }
             } else if (isComposedSchema(ref)) {
                 return schema;
             } else if (isMapSchema(ref)) {
                 if (ref.getProperties() != null && !ref.getProperties().isEmpty()) // has at least one property
                     return schema; // treat it as model
                 else {
-                    // treat it as a typical map
-                    return unaliasSchema(allSchemas, allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())));
+                    if (generateAliasAsModel) {
+                        return schema; // generate a model extending map
+                    } else {
+                        // treat it as a typical map
+                        return unaliasSchema(allSchemas, allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())));
+                    }
                 }
             } else if (isObjectSchema(ref)) { // model
                 if (ref.getProperties() != null && !ref.getProperties().isEmpty()) { // has at least one property