Issue #6471 Add java8, interfaceOnly, delegatePattern to generated server stubs (#6476)

* java 8 interface only delegate method mode

* typo correction

* Update samples with ./bin/spring-all-petstore.sh

* change delegate prefix to "do" and make delegate method a default method that returns an OK status code

* remove temp debug printout

* prefix spring annotated method with "_" to indicate that is private

* resolve merge issues from Merge of remote-tracking branch 'upstream/master'

* tuned whitespace in api.mustache and re-ran spring-all-petstore.sh

* removed special spring cloud library check as it was no longer being referenced in api.mustache
re-ran spring-all-petstore.sh

Author: david-noel

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/SpringCodegen.java

@@ -39,6 +39,7 @@ public class SpringCodegen extends AbstractJavaCodegen
     protected String basePackage = "io.swagger";
     protected boolean interfaceOnly = false;
     protected boolean delegatePattern = false;
+    protected boolean delegateMethod = false;
     protected boolean singleContentTypes = false;
     protected boolean java8 = false;
     protected boolean async = false;
@@ -206,8 +207,14 @@ public void processOpts() {
         }
 
         if (this.interfaceOnly && this.delegatePattern) {
-            throw new IllegalArgumentException(
-                    String.format("Can not generate code with `%s` and `%s` both true.", DELEGATE_PATTERN, INTERFACE_ONLY));
+            if (this.java8) {
+                this.delegateMethod = true;
+                additionalProperties.put("delegate-method", true);
+            } else {
+                throw new IllegalArgumentException(
+                        String.format("Can not generate code with `%s` and `%s` true while `%s` is false.",
+                                DELEGATE_PATTERN, INTERFACE_ONLY, JAVA_8));
+            }
         }
 
         if (!this.interfaceOnly) {
@@ -273,12 +280,12 @@ public void processOpts() {
             }
         }
 
-        if (!this.delegatePattern && this.java8) {
+        if ((!this.delegatePattern && this.java8) || this.delegateMethod) {
             additionalProperties.put("jdk8-no-delegate", true);
         }
 
 
-        if (this.delegatePattern) {
+        if (this.delegatePattern && !this.delegateMethod) {
             additionalProperties.put("isDelegate", "true");
             apiTemplateFiles.put("apiDelegate.mustache", "Delegate.java");
         }

modules/swagger-codegen/src/main/resources/JavaSpring/api.mustache

@@ -100,7 +100,14 @@ public interface {{classname}} {
         produces = { {{#produces}}"{{{mediaType}}}"{{#hasMore}}, {{/hasMore}}{{/produces}} }, {{/hasProduces}}{{#hasConsumes}}
         consumes = { {{#consumes}}"{{{mediaType}}}"{{#hasMore}}, {{/hasMore}}{{/consumes}} },{{/hasConsumes}}{{/singleContentTypes}}
         method = RequestMethod.{{httpMethod}})
-    {{#jdk8}}default {{/jdk8}}{{#responseWrapper}}{{.}}<{{/responseWrapper}}ResponseEntity<{{>returnTypes}}>{{#responseWrapper}}>{{/responseWrapper}} {{operationId}}({{#allParams}}{{>queryParams}}{{>pathParams}}{{>headerParams}}{{>bodyParams}}{{>formParams}}{{#hasMore}},{{/hasMore}}{{/allParams}}){{^jdk8}};{{/jdk8}}{{#jdk8}} {
+    {{#jdk8}}default {{/jdk8}}{{#responseWrapper}}{{.}}<{{/responseWrapper}}ResponseEntity<{{>returnTypes}}>{{#responseWrapper}}>{{/responseWrapper}} {{#delegate-method}}_{{/delegate-method}}{{operationId}}({{#allParams}}{{>queryParams}}{{>pathParams}}{{>headerParams}}{{>bodyParams}}{{>formParams}}{{#hasMore}},{{/hasMore}}{{/allParams}}){{^jdk8}};{{/jdk8}}{{#jdk8}} {
+        {{#delegate-method}}
+        return {{operationId}}({{#allParams}}{{paramName}}{{#hasMore}}, {{/hasMore}}{{/allParams}});
+    }
+
+    // Override this method
+    default {{#responseWrapper}}{{.}}<{{/responseWrapper}}ResponseEntity<{{>returnTypes}}>{{#responseWrapper}}>{{/responseWrapper}} {{operationId}}({{#allParams}}{{^isFile}}{{{dataType}}}{{/isFile}}{{#isFile}}MultipartFile{{/isFile}} {{paramName}}{{#hasMore}},{{/hasMore}}{{/allParams}}) {
+        {{/delegate-method}}
         {{^isDelegate}}
         if(getObjectMapper().isPresent() && getAcceptHeader().isPresent()) {
         {{#examples}}
@@ -125,4 +132,4 @@ public interface {{classname}} {
 
 {{/operation}}
 }
-{{/operations}}
+{{/operations}}