Add WithHttpInfo API methods to Java okhttp-gson client

to allow accessing response status code and headers
and removed the methods of recording last response info from
ApiClient.

modules/swagger-codegen/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache

@@ -104,9 +104,6 @@ public class ApiClient {
 
   private Map<String, Authentication> authentications;
 
-  private int statusCode;
-  private Map<String, List<String>> responseHeaders;
-
   private DateFormat dateFormat;
   private DateFormat datetimeFormat;
   private boolean lenientDatetimeFormat;
@@ -177,24 +174,6 @@ public class ApiClient {
     return this;
   }
 
-  /**
-   * Gets the status code of the previous request.
-   * NOTE: Status code of last async response is not recorded here, it is
-   * passed to the callback methods instead.
-   */
-  public int getStatusCode() {
-    return statusCode;
-  }
-
-  /**
-   * Gets the response headers of the previous request.
-   * NOTE: Headers of last async response is not recorded here, it is passed
-   * to callback methods instead.
-   */
-  public Map<String, List<String>> getResponseHeaders() {
-    return responseHeaders;
-  }
-
   public boolean isVerifyingSsl() {
     return verifyingSsl;
   }
@@ -731,7 +710,7 @@ public class ApiClient {
   /**
    * @see #execute(Call, Type)
    */
-  public <T> T execute(Call call) throws ApiException {
+  public <T> ApiResponse<T> execute(Call call) throws ApiException {
     return execute(call, null);
   }
 
@@ -740,14 +719,15 @@ public class ApiClient {
    *
    * @param returnType The return type used to deserialize HTTP response body
    * @param <T> The return type corresponding to (same with) returnType
-   * @return The Java object deserialized from response body. Returns null if returnType is null.
+   * @return <code>ApiResponse</code> object containing response status, headers and
+   *   data, which is a Java object deserialized from response body and would be null
+   *   when returnType is null.
    */
-  public <T> T execute(Call call, Type returnType) throws ApiException {
+  public <T> ApiResponse<T> execute(Call call, Type returnType) throws ApiException {
     try {
       Response response = call.execute();
-      this.statusCode = response.code();
-      this.responseHeaders = response.headers().toMultimap();
-      return handleResponse(response, returnType);
+      T data = handleResponse(response, returnType);
+      return new ApiResponse<T>(response.code(), response.headers().toMultimap(), data);
     } catch (IOException e) {
       throw new ApiException(e);
     }

modules/swagger-codegen/src/main/resources/Java/libraries/okhttp-gson/ApiResponse.mustache

@@ -0,0 +1,32 @@
+package {{invokerPackage}};
+
+import java.util.List;
+import java.util.Map;
+
+public class ApiResponse<T> {
+  final private int statusCode;
+  final private Map<String, List<String>> headers;
+  final private T data;
+
+  public ApiResponse(int statusCode, Map<String, List<String>> headers) {
+    this(statusCode, headers, null);
+  }
+
+  public ApiResponse(int statusCode, Map<String, List<String>> headers, T data) {
+    this.statusCode = statusCode;
+    this.headers = headers;
+    this.data = data;
+  }
+
+  public int getStatusCode() {
+    return statusCode;
+  }
+
+  public Map<String, List<String>> getHeaders() {
+    return headers;
+  }
+
+  public T getData() {
+    return data;
+  }
+}

modules/swagger-codegen/src/main/resources/Java/libraries/okhttp-gson/api.mustache

@@ -3,6 +3,7 @@ package {{package}};
 import {{invokerPackage}}.ApiCallback;
 import {{invokerPackage}}.ApiClient;
 import {{invokerPackage}}.ApiException;
+import {{invokerPackage}}.ApiResponse;
 import {{invokerPackage}}.Configuration;
 import {{invokerPackage}}.Pair;
 import {{invokerPackage}}.ProgressRequestBody;
@@ -106,9 +107,20 @@ public class {{classname}} {
    * @return {{{returnType}}}{{/returnType}}
    */
   public {{#returnType}}{{{returnType}}} {{/returnType}}{{^returnType}}void {{/returnType}}{{operationId}}({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws ApiException {
+    {{#returnType}}ApiResponse<{{{returnType}}}> {{localVariablePrefix}}resp = {{/returnType}}{{operationId}}WithHttpInfo({{#allParams}}{{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}});{{#returnType}}
+    return {{localVariablePrefix}}resp.getData();{{/returnType}}
+  }
+
+  /**
+   * {{summary}}
+   * {{notes}}{{#allParams}}
+   * @param {{paramName}} {{description}}{{/allParams}}
+   * @return ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Void{{/returnType}}>
+   */
+  public ApiResponse<{{#returnType}}{{{returnType}}}{{/returnType}}{{^returnType}}Void{{/returnType}}> {{operationId}}WithHttpInfo({{#allParams}}{{{dataType}}} {{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}}) throws ApiException {
     Call {{localVariablePrefix}}call = {{operationId}}Call({{#allParams}}{{paramName}}, {{/allParams}}null, null);
     {{#returnType}}Type {{localVariablePrefix}}returnType = new TypeToken<{{{returnType}}}>(){}.getType();
-    return {{localVariablePrefix}}apiClient.execute({{localVariablePrefix}}call, {{localVariablePrefix}}returnType);{{/returnType}}{{^returnType}}{{localVariablePrefix}}apiClient.execute({{localVariablePrefix}}call);{{/returnType}}
+    return {{localVariablePrefix}}apiClient.execute({{localVariablePrefix}}call, {{localVariablePrefix}}returnType);{{/returnType}}{{^returnType}}return {{localVariablePrefix}}apiClient.execute({{localVariablePrefix}}call);{{/returnType}}
   }
 
   /**