refactor(client): migrate to io.github.bsayli namespace and update docs

- Moved all packages from com.example.demo.client → io.github.bsayli.openapi.client
- Updated pom.xml with new groupId and OpenAPI generator package paths
- Adjusted api_wrapper.mustache to use FQN base class
- Fixed OpenAPI spec (201 response, server URL) for alignment with demo service
- Updated README.md to reflect new package structure and usage examples
- Replaced generated-client-wrapper.png with updated image reflecting new namespace

Author: barissayli

customer-service-client/README.md

@@ -1,25 +1,22 @@
 # customer-service-client
 
-Generated Java client for the demo **customer-service**, showcasing **type‑safe generic responses** with OpenAPI + a tiny custom template (wrapping payloads in a reusable `ApiClientResponse<T>`).
+Generated Java client for the demo **customer-service**, showcasing **type‑safe generic responses** with OpenAPI + a custom Mustache template (wrapping payloads in a reusable `ApiClientResponse<T>`).
 
----
-
-## ✅ What you get
-
-* Generated code using **OpenAPI Generator** (`restclient` with Spring Framework `RestClient`)
-* A thin wrapper class per endpoint (e.g. `ApiResponseCustomerCreateResponse`) that **extends**:
+This module demonstrates how to evolve OpenAPI Generator with minimal customization to support generic response envelopes — avoiding duplicated wrappers and preserving strong typing.
 
-    * `src/main/java/com/example/demo/client/common/ApiClientResponse.java`
-* Minimal Spring wiring to expose the generated API as beans:
+---
 
-    * `com.example.demo.client.adapter.config.CustomerApiClientConfig`
-* A focused integration test with **OkHttp MockWebServer**:
+## ✅ What You Get
 
-    * `com.example.demo.client.adapter.CustomerClientIT`
+* Generated code using **OpenAPI Generator** (`restclient` with Spring Framework `RestClient`).
+* A reusable generic base: `io.github.bsayli.openapi.client.common.ApiClientResponse<T>`.
+* Thin wrappers per endpoint (e.g. `ApiResponseCustomerCreateResponse`) that extend the base.
+* Spring Boot configuration to auto‑expose the client as beans.
+* A focused integration test using **OkHttp MockWebServer**.
 
 ---
 
-## 🧪 Quick pipeline (3 steps)
+## 🚀 Quick Pipeline (3 Steps)
 
 1. **Run the sample service**
 
@@ -37,118 +34,158 @@ curl -s http://localhost:8084/customer/v3/api-docs.yaml \
   -o src/main/resources/customer-api-docs.yaml
 ```
 
-> You can also skip this if the spec is already checked in.
-
 3. **Generate & build the client**
 
 ```bash
 mvn clean install
 ```
 
-Generated sources will land under:
+Generated sources will be placed under:
 
 ```
 target/generated-sources/openapi/src/gen/java/main
 ```
 
 ---
 
-## 🚀 Using the client in your application
+## 🧩 Using the Client
 
-### Option A — Spring configuration (recommended)
+### Option A — Spring Configuration (recommended)
 
-Add this module as a dependency and set the base URL. The module contributes a small configuration:
+Include this module as a dependency and configure the base URL:
 
 ```java
 @Configuration
 public class CustomerApiClientConfig {
+
   @Bean
   public RestClient customerRestClient(RestClient.Builder builder,
                                        @Value("${customer.api.base-url}") String baseUrl) {
     return builder.baseUrl(baseUrl).build();
   }
 
   @Bean
-  public com.example.demo.client.generated.invoker.ApiClient customerApiClient(
+  public io.github.bsayli.openapi.client.generated.invoker.ApiClient customerApiClient(
       RestClient customerRestClient,
       @Value("${customer.api.base-url}") String baseUrl) {
-    return new com.example.demo.client.generated.invoker.ApiClient(customerRestClient)
+    return new io.github.bsayli.openapi.client.generated.invoker.ApiClient(customerRestClient)
         .setBasePath(baseUrl);
   }
 
   @Bean
-  public com.example.demo.client.generated.api.CustomerControllerApi customerControllerApi(
-      com.example.demo.client.generated.invoker.ApiClient apiClient) {
-    return new com.example.demo.client.generated.api.CustomerControllerApi(apiClient);
+  public io.github.bsayli.openapi.client.generated.api.CustomerControllerApi customerControllerApi(
+      io.github.bsayli.openapi.client.generated.invoker.ApiClient apiClient) {
+    return new io.github.bsayli.openapi.client.generated.api.CustomerControllerApi(apiClient);
   }
 }
 ```
 
-**Configure the base URL** in your app:
+**application.properties:**
 
 ```properties
 customer.api.base-url=http://localhost:8084/customer
 ```
 
-**Call the API**:
+**Usage example:**
 
 ```java
 @Autowired
-private com.example.demo.client.generated.api.CustomerControllerApi customerApi;
+private io.github.bsayli.openapi.client.generated.api.CustomerControllerApi customerApi;
 
 public void createCustomer() {
-  var req = new com.example.demo.client.generated.dto.CustomerCreateRequest()
+  var req = new io.github.bsayli.openapi.client.generated.dto.CustomerCreateRequest()
       .name("Jane Doe")
       .email("jane@example.com");
 
   var resp = customerApi.create(req); // ApiResponseCustomerCreateResponse
+
   System.out.println(resp.getStatus());                 // 201
   System.out.println(resp.getData().getCustomer().getName()); // "Jane Doe"
 }
 ```
 
-### Option B — Manual wiring (no Spring context)
+### Option B — Manual Wiring (no Spring context)
 
 ```java
 var rest = RestClient.builder().baseUrl("http://localhost:8084/customer").build();
-var apiClient = new com.example.demo.client.generated.invoker.ApiClient(rest)
+var apiClient = new io.github.bsayli.openapi.client.generated.invoker.ApiClient(rest)
     .setBasePath("http://localhost:8084/customer");
-var customerApi = new com.example.demo.client.generated.api.CustomerControllerApi(apiClient);
+var customerApi = new io.github.bsayli.openapi.client.generated.api.CustomerControllerApi(apiClient);
+```
+
+---
+
+## 🧩 Adapter Pattern Example
+
+For larger applications, encapsulate the generated API in an adapter:
+
+```java
+package io.github.bsayli.openapi.client.adapter.impl;
+
+import io.github.bsayli.openapi.client.adapter.CustomerClientAdapter;
+import io.github.bsayli.openapi.client.common.ApiClientResponse;
+import io.github.bsayli.openapi.client.generated.api.CustomerControllerApi;
+import io.github.bsayli.openapi.client.generated.dto.CustomerCreateRequest;
+import io.github.bsayli.openapi.client.generated.dto.CustomerCreateResponse;
+import org.springframework.stereotype.Service;
+
+@Service
+public class CustomerClientAdapterImpl implements CustomerClientAdapter {
+
+    private final CustomerControllerApi customerControllerApi;
+
+    public CustomerClientAdapterImpl(CustomerControllerApi customerControllerApi) {
+        this.customerControllerApi = customerControllerApi;
+    }
+
+    @Override
+    public ApiClientResponse<CustomerCreateResponse> create(CustomerCreateRequest request) {
+        return customerControllerApi.create(request);
+    }
+}
 ```
 
+This ensures:
+
+* Generated code stays isolated.
+* Business code depends only on the adapter interface.
+
 ---
 
-## 🧩 How the generics work
+## 🧩 How the Generics Work
 
-The template at `src/main/resources/openapi-templates/api_wrapper.mustache` emits thin wrappers like:
+The template at `src/main/resources/openapi-templates/api_wrapper.mustache` emits wrappers like:
 
 ```java
+import io.github.bsayli.openapi.client.common.ApiClientResponse;
+
 // e.g., ApiResponseCustomerCreateResponse
 public class ApiResponseCustomerCreateResponse
-    extends com.example.demo.client.common.ApiClientResponse<CustomerCreateResponse> { }
+        extends ApiClientResponse<CustomerCreateResponse> {
+}
 ```
 
-Only `api_wrapper.mustache` is customized for this demo; **all other models** use the stock templates/behavior.
+Only this Mustache partial is customized. All other models use stock templates.
 
 ---
 
 ## 🧪 Tests
 
-Run the integration-style test with MockWebServer:
+Integration test with MockWebServer:
 
 ```bash
 mvn -q -DskipITs=false test
 ```
 
-It enqueues a `201` response and asserts mapping into `ApiResponseCustomerCreateResponse`.
+It enqueues a `201` response and asserts correct mapping into `ApiResponseCustomerCreateResponse`.
 
 ---
 
 ## 📚 Notes
 
-* Dependencies like `spring-web`, `spring-context`, `jackson-*`, `jakarta.*` are marked **provided**. Your host app supplies them.
+* Dependencies like `spring-web`, `spring-context`, `jackson-*`, `jakarta.*` are marked **provided**; your host app supplies them.
 * Generator options: Spring 6 `RestClient`, Jakarta EE, Jackson, Java 21.
-* OpenAPI spec path used by the build:
+* OpenAPI spec path:
 
 ```
 src/main/resources/customer-api-docs.yaml
@@ -158,4 +195,4 @@ src/main/resources/customer-api-docs.yaml
 
 ## 🛡 License
 
-This repository is licensed under **MIT** (root `LICENSE`). Submodules don’t duplicate license files; the root license applies.
+This repository is licensed under **MIT** (root `LICENSE`). Submodules inherit the license.

customer-service-client/pom.xml

@@ -4,7 +4,7 @@
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
 
-    <groupId>com.example.demo</groupId>
+    <groupId>io.github.bsayli</groupId>
     <artifactId>customer-service-client</artifactId>
     <version>0.1.0</version>
     <name>customer-service-client</name>
@@ -124,9 +124,9 @@
                             <output>${project.build.directory}/generated-sources/openapi</output>
 
                             <!-- Packages for generated code -->
-                            <apiPackage>com.example.demo.client.generated.api</apiPackage>
-                            <modelPackage>com.example.demo.client.generated.dto</modelPackage>
-                            <invokerPackage>com.example.demo.client.generated.invoker</invokerPackage>
+                            <apiPackage>io.github.bsayli.openapi.client.generated.api</apiPackage>
+                            <modelPackage>io.github.bsayli.openapi.client.generated.dto</modelPackage>
+                            <invokerPackage>io.github.bsayli.openapi.client.generated.invoker</invokerPackage>
 
                             <!-- Use our custom templates that implement generics-aware wrappers -->
                             <templateDirectory>${project.basedir}/src/main/resources/openapi-templates</templateDirectory>

customer-service-client/src/main/java/com/example/demo/client/adapter/CustomerClientAdapter.java

@@ -0,0 +1,9 @@
+package io.github.bsayli.openapi.client.adapter;
+
+import io.github.bsayli.openapi.client.common.ApiClientResponse;
+import io.github.bsayli.openapi.client.generated.dto.CustomerCreateRequest;
+import io.github.bsayli.openapi.client.generated.dto.CustomerCreateResponse;
+
+public interface CustomerClientAdapter {
+    ApiClientResponse<CustomerCreateResponse> create(CustomerCreateRequest request);
+}

customer-service-client/src/main/java/io/github/bsayli/openapi/client/adapter/CustomerClientAdapter.java

@@ -1,7 +1,7 @@
-package com.example.demo.client.adapter.config;
+package io.github.bsayli.openapi.client.adapter.config;
 
-import com.example.demo.client.generated.api.CustomerControllerApi;
-import com.example.demo.client.generated.invoker.ApiClient;
+import io.github.bsayli.openapi.client.generated.api.CustomerControllerApi;
+import io.github.bsayli.openapi.client.generated.invoker.ApiClient;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;

customer-service-client/src/main/java/com/example/demo/client/adapter/config/CustomerApiClientConfig.java renamed to customer-service-client/src/main/java/io/github/bsayli/openapi/client/adapter/config/CustomerApiClientConfig.java

@@ -1,10 +1,10 @@
-package com.example.demo.client.adapter.impl;
+package io.github.bsayli.openapi.client.adapter.impl;
 
-import com.example.demo.client.adapter.CustomerClientAdapter;
-import com.example.demo.client.common.ApiClientResponse;
-import com.example.demo.client.generated.api.CustomerControllerApi;
-import com.example.demo.client.generated.dto.CustomerCreateRequest;
-import com.example.demo.client.generated.dto.CustomerCreateResponse;
+import io.github.bsayli.openapi.client.adapter.CustomerClientAdapter;
+import io.github.bsayli.openapi.client.common.ApiClientResponse;
+import io.github.bsayli.openapi.client.generated.api.CustomerControllerApi;
+import io.github.bsayli.openapi.client.generated.dto.CustomerCreateRequest;
+import io.github.bsayli.openapi.client.generated.dto.CustomerCreateResponse;
 import org.springframework.stereotype.Service;
 
 @Service

customer-service-client/src/main/java/com/example/demo/client/adapter/impl/CustomerClientAdapterImpl.java renamed to customer-service-client/src/main/java/io/github/bsayli/openapi/client/adapter/impl/CustomerClientAdapterImpl.java

@@ -1,4 +1,4 @@
-package com.example.demo.client.common;
+package io.github.bsayli.openapi.client.common;
 
 public record ApiClientError(String errorCode, String message) {
 }

customer-service-client/src/main/java/com/example/demo/client/common/ApiClientError.java renamed to customer-service-client/src/main/java/io/github/bsayli/openapi/client/common/ApiClientError.java

@@ -1,4 +1,4 @@
-package com.example.demo.client.common;
+package io.github.bsayli.openapi.client.common;
 
 import java.util.List;
 import java.util.Objects;

customer-service-client/src/main/java/com/example/demo/client/common/ApiClientResponse.java renamed to customer-service-client/src/main/java/io/github/bsayli/openapi/client/common/ApiClientResponse.java

@@ -4,7 +4,7 @@ info:
   description: "Demo: type-safe generic API responses with OpenAPI"
   version: 0.1.0
 servers:
-  - url: http://localhost:8084/customer/customer
+  - url: http://localhost:8084/customer
     description: Local service URL
 paths:
   /v1/customers:

customer-service-client/src/main/resources/customer-api-docs.yaml

@@ -1,4 +1,4 @@
-import com.example.demo.client.common.ApiClientResponse;
+import io.github.bsayli.openapi.client.common.ApiClientResponse;
 
 public class {{classname}} extends ApiClientResponse<{{vendorExtensions.x-api-wrapper-datatype}}> {
 }