feat: [JAVA] [resttemplate] [#13146] added support for abstract file

modules/openapi-generator/src/main/resources/Java/libraries/resttemplate/api.mustache

@@ -74,7 +74,7 @@ public class {{classname}} {
     {{#isDeprecated}}
     @Deprecated
     {{/isDeprecated}}
-    public {{#returnType}}{{{.}}} {{/returnType}}{{^returnType}}void {{/returnType}}{{operationId}}({{#allParams}}{{#isFile}}{{#useAbstractionForFiles}}{{#collectionFormat}}java.util.Collection<org.springframework.core.io.Resource>{{/collectionFormat}}{{^collectionFormat}}org.springframework.core.io.Resource{{/collectionFormat}}{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{dataType}}}{{/useAbstractionForFiles}}{{/isFile}}{{^isFile}}{{{dataType}}}{{/isFile}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}) throws RestClientException {
+    public {{#returnType}}{{#isResponseFile}}{{#useAbstractionForFiles}}org.springframework.core.io.Resource{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{.}}}{{/useAbstractionForFiles}}{{/isResponseFile}}{{^isResponseFile}}{{{.}}}{{/isResponseFile}} {{/returnType}}{{^returnType}}void {{/returnType}}{{operationId}}({{#allParams}}{{#isFile}}{{#useAbstractionForFiles}}{{#collectionFormat}}java.util.Collection<org.springframework.core.io.Resource>{{/collectionFormat}}{{^collectionFormat}}org.springframework.core.io.Resource{{/collectionFormat}}{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{dataType}}}{{/useAbstractionForFiles}}{{/isFile}}{{^isFile}}{{{dataType}}}{{/isFile}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}) throws RestClientException {
         {{#returnType}}
         return {{operationId}}WithHttpInfo({{#allParams}}{{paramName}}{{^-last}}, {{/-last}}{{/allParams}}).getBody();
         {{/returnType}}
@@ -105,7 +105,7 @@ public class {{classname}} {
     {{#isDeprecated}}
     @Deprecated
     {{/isDeprecated}}
-    public ResponseEntity<{{{returnType}}}{{^returnType}}Void{{/returnType}}> {{operationId}}WithHttpInfo({{#allParams}}{{#isFile}}{{#useAbstractionForFiles}}{{#collectionFormat}}java.util.Collection<org.springframework.core.io.Resource>{{/collectionFormat}}{{^collectionFormat}}org.springframework.core.io.Resource{{/collectionFormat}}{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{dataType}}}{{/useAbstractionForFiles}}{{/isFile}}{{^isFile}}{{{dataType}}}{{/isFile}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}) throws RestClientException {
+    public ResponseEntity<{{#returnType}}{{#isResponseFile}}{{#useAbstractionForFiles}}org.springframework.core.io.Resource{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{.}}}{{/useAbstractionForFiles}}{{/isResponseFile}}{{^isResponseFile}}{{{.}}}{{/isResponseFile}}{{/returnType}}{{^returnType}}Void{{/returnType}}> {{operationId}}WithHttpInfo({{#allParams}}{{#isFile}}{{#useAbstractionForFiles}}{{#collectionFormat}}java.util.Collection<org.springframework.core.io.Resource>{{/collectionFormat}}{{^collectionFormat}}org.springframework.core.io.Resource{{/collectionFormat}}{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{dataType}}}{{/useAbstractionForFiles}}{{/isFile}}{{^isFile}}{{{dataType}}}{{/isFile}} {{paramName}}{{^-last}}, {{/-last}}{{/allParams}}) throws RestClientException {
         Object localVarPostBody = {{#bodyParam}}{{paramName}}{{/bodyParam}}{{^bodyParam}}null{{/bodyParam}};
         {{#allParams}}{{#required}}
         // verify the required parameter '{{paramName}}' is set
@@ -148,7 +148,7 @@ public class {{classname}} {
 
         String[] localVarAuthNames = new String[] { {{#authMethods}}"{{name}}"{{^-last}}, {{/-last}}{{/authMethods}} };
 
-        {{#returnType}}ParameterizedTypeReference<{{{returnType}}}> localReturnType = new ParameterizedTypeReference<{{{returnType}}}>() {};{{/returnType}}{{^returnType}}ParameterizedTypeReference<Void> localReturnType = new ParameterizedTypeReference<Void>() {};{{/returnType}}
+        {{#returnType}}ParameterizedTypeReference<{{#returnType}}{{#isResponseFile}}{{#useAbstractionForFiles}}org.springframework.core.io.Resource{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{.}}}{{/useAbstractionForFiles}}{{/isResponseFile}}{{^isResponseFile}}{{{.}}}{{/isResponseFile}}{{/returnType}}> localReturnType = new ParameterizedTypeReference<{{#returnType}}{{#isResponseFile}}{{#useAbstractionForFiles}}org.springframework.core.io.Resource{{/useAbstractionForFiles}}{{^useAbstractionForFiles}}{{{.}}}{{/useAbstractionForFiles}}{{/isResponseFile}}{{^isResponseFile}}{{{.}}}{{/isResponseFile}}{{/returnType}}>() {};{{/returnType}}{{^returnType}}ParameterizedTypeReference<Void> localReturnType = new ParameterizedTypeReference<Void>() {};{{/returnType}}
         return apiClient.invokeAPI("{{{path}}}", HttpMethod.{{httpMethod}}, {{#hasPathParams}}uriVariables{{/hasPathParams}}{{^hasPathParams}}Collections.<String, Object>emptyMap(){{/hasPathParams}}, localVarQueryParams, localVarPostBody, localVarHeaderParams, localVarCookieParams, localVarFormParams, localVarAccept, localVarContentType, localVarAuthNames, localReturnType);
     }
     {{/operation}}

modules/openapi-generator/src/test/java/org/openapitools/codegen/java/JavaClientCodegenTest.java

@@ -1573,6 +1573,38 @@ public void testWebClientJsonCreatorWithNullable_issue12790() throws Exception {
             );
     }
 
+    @Test
+    public void testRestTemplateResponseTypeWithUseAbstractionForFiles() throws IOException {
+
+        Map<String, Object> properties = new HashMap<>();
+        properties.put(CodegenConstants.API_PACKAGE, "xyz.abcdef.api");
+        properties.put(JavaClientCodegen.USE_ABSTRACTION_FOR_FILES, true);
+
+        File output = Files.createTempDirectory("test").toFile();
+        output.deleteOnExit();
+
+        final CodegenConfigurator configurator = new CodegenConfigurator()
+                .setGeneratorName("java")
+                .setLibrary(JavaClientCodegen.RESTTEMPLATE)
+                .setAdditionalProperties(properties)
+                .setInputSpec("src/test/resources/3_0/issue13146_file_abstraction_response.yaml")
+                .setOutputDir(output.getAbsolutePath().replace("\\", "/"));
+
+
+        DefaultGenerator generator = new DefaultGenerator();
+        List<File> files = generator.opts(configurator.toClientOptInput()).generate();
+        files.forEach(File::deleteOnExit);
+
+        validateJavaSourceFiles(files);
+
+        Path defaultApi = Paths.get(output + "/src/main/java/xyz/abcdef/api/ResourceApi.java");
+        TestUtils.assertFileContains(defaultApi,
+                                     "org.springframework.core.io.Resource resourceInResponse()",
+                                     "ResponseEntity<org.springframework.core.io.Resource> resourceInResponseWithHttpInfo()",
+                                     "ParameterizedTypeReference<org.springframework.core.io.Resource> localReturnType = new ParameterizedTypeReference<org.springframework.core.io.Resource>()"
+        );
+    }
+
     public void testExtraAnnotations(String library) throws IOException {
         File output = Files.createTempDirectory("test").toFile().getCanonicalFile();
         output.deleteOnExit();

modules/openapi-generator/src/test/resources/3_0/issue13146_file_abstraction_response.yaml

@@ -0,0 +1,19 @@
+openapi: '3.0.1'
+info:
+  version: 1.0.0
+  title: Response file abstraction test
+paths:
+  /resource:
+    get:
+      tags:
+        - resource
+      description: Response file abstraction
+      operationId: resourceInResponse
+      responses:
+        '200':
+          description: Successful operation
+          content:
+            application/octet-stream:
+              schema:
+                type: string
+                format: binary