Use the string representation for serializing enum values with Jackson

Created by: jfacorro

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
• Filed the PR against the correct branch: master, 3.3.x, 4.0.x. Default: master.
• Copied the technical committee to review the pull request if your PR is targeting a particular programming language.

Description of the PR

The current serialization of enums when using Jackson is always generating uppercase values. This violates what's in the spec for the cases when the different enum values contain lower case letters.

The only significant change is in the modelEnum.mustache file, all other changes are the result of running the bin/java-jaxrs-petstore-server-all.sh script (except for the bump in version for Jackson from 2.8.9 to 2.9.0).

modules/openapi-generator/src/main/resources/JavaJaxRS/cxf/enumOuterClass.mustache

@@ -26,16 +26,15 @@ public enum {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum
   }
 
   @Override
-{{#jackson}}
+  {{#jackson}}
   @JsonValue
-{{/jackson}}  
+  {{/jackson}}
   public String toString() {
     return String.valueOf(value);
   }
 
-{{#jackson}}
+  {{#jackson}}
   @JsonCreator
-{{/jackson}}
   public static {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} fromValue(String text) {
     for ({{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} b : {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.values()) {
       if (String.valueOf(b.value).equals(text)) {
@@ -44,5 +43,5 @@ public enum {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum
     }
     {{#useNullForUnknownEnumValue}}return null;{{/useNullForUnknownEnumValue}}{{^useNullForUnknownEnumValue}}throw new IllegalArgumentException("Unexpected value '" + text + "'");{{/useNullForUnknownEnumValue}}
   }
-  
+  {{/jackson}}
 }

modules/openapi-generator/src/main/resources/JavaJaxRS/resteasy/eap/enumClass.mustache

@@ -17,7 +17,9 @@
     }
 
     @Override
+    {{#jackson}}
     @JsonValue
+    {{/jackson}}
     public String toString() {
       return String.valueOf(value);
     }

modules/openapi-generator/src/main/resources/JavaJaxRS/resteasy/enumClass.mustache

@@ -17,7 +17,9 @@
     }
 
     @Override
+    {{#jackson}}
     @JsonValue
+    {{/jackson}}
     public String toString() {
       return String.valueOf(value);
     }

modules/openapi-generator/src/main/resources/JavaJaxRS/spec/enumClass.mustache

@@ -16,11 +16,14 @@ public enum {{datatypeWithEnum}} {
     }
 
     @Override
+    {{#jackson}}
     @JsonValue
+    {{/jackson}}
     public String toString() {
         return String.valueOf(value);
     }
 
+    {{#jackson}}
     @JsonCreator
     public static {{datatypeWithEnum}} fromValue(String v) {
         for ({{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} b : {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.values()) {
@@ -30,4 +33,5 @@ public enum {{datatypeWithEnum}} {
         }
         {{#useNullForUnknownEnumValue}}return null;{{/useNullForUnknownEnumValue}}{{^useNullForUnknownEnumValue}}throw new IllegalArgumentException("Unexpected value '" + v + "'");{{/useNullForUnknownEnumValue}}
     }
+    {{/jackson}}
 }

modules/openapi-generator/src/main/resources/JavaJaxRS/spec/enumOuterClass.mustache

@@ -26,11 +26,14 @@ public enum {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum
   }
 
   @Override
+  {{#jackson}}
   @JsonValue
+  {{/jackson}}
   public String toString() {
     return String.valueOf(value);
   }
 
+  {{#jackson}}
   @JsonCreator
   public static {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} fromValue(String text) {
     for ({{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}} b : {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum}}{{{classname}}}{{/datatypeWithEnum}}.values()) {
@@ -40,4 +43,5 @@ public enum {{#datatypeWithEnum}}{{{.}}}{{/datatypeWithEnum}}{{^datatypeWithEnum
     }
     {{#useNullForUnknownEnumValue}}return null;{{/useNullForUnknownEnumValue}}{{^useNullForUnknownEnumValue}}throw new IllegalArgumentException("Unexpected value '" + text + "'");{{/useNullForUnknownEnumValue}}
   }
+  {{/jackson}}
 }