add schema handle method on codegen config interface.

Author: HugoMario

modules/swagger-codegen/src/main/java/io/swagger/codegen/v3/CodegenConfig.java

@@ -243,4 +243,6 @@ public interface CodegenConfig {
     void setIgnoreImportMapping(boolean ignoreImportMapping);
 
     boolean defaultIgnoreImportMappingOption();
+
+    ISchemaHandler getSchemaHandler();
 }

modules/swagger-codegen/src/main/java/io/swagger/codegen/v3/DefaultGenerator.java

@@ -386,13 +386,12 @@ public int compare(String o1, String o2) {
                 throw new RuntimeException("Could not process model '" + name + "'" + ".Please make sure that your schema is correct!", e);
             }
         }
-        final List<CodegenModel> composedModels = null;
-        /** todo: uncomment once generator repo is updated
+
         final ISchemaHandler schemaHandler = config.getSchemaHandler();
         schemaHandler.readProcessedModels(allProcessedModels);
 
         final List<CodegenModel> composedModels = schemaHandler.getModels();
-         */
+
          if (composedModels != null && !composedModels.isEmpty()) {
             for (CodegenModel composedModel : composedModels) {
                 final Map<String, Object> models = processModel(composedModel, config, schemas);