moved serializationLibrary Kotlin specific values to AbstractKotlinCo…

…degen. I picked this layer instead of KotlinClient to make it available to the server in the future. In this commit, I've also updated kotlin.md to document serializationLibrary kotlin options. Testing: re-run mvn clean install and mvn verify

docs/generators/kotlin.md

@@ -17,3 +17,4 @@ sidebar_label: kotlin
 |parcelizeModels|toggle "@Parcelize" for generated models| |null|
 |dateLibrary|Option. Date library to use|<dl><dt>**string**</dt><dd>String</dd><dt>**java8**</dt><dd>Java 8 native JSR310</dd><dt>**threetenbp**</dt><dd>Threetenbp</dd><dl>|java8|
 |collectionType|Option. Collection type to use|<dl><dt>**array**</dt><dd>kotlin.Array</dd><dt>**list**</dt><dd>kotlin.collections.List</dd><dl>|array|
+|serializationLibrary|Option. JSON serialization library to use|<dl><dt>**moshi**</dt><dd>https://github.com/square/moshi</dd><dt>**gson**</dt><dd>https://github.com/google/gson</dd><dl>|moshi|

modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenConstants.java

@@ -202,9 +202,9 @@ public static enum ENUM_PROPERTY_NAMING_TYPE {camelCase, PascalCase, snake_case,
     public static final String ENUM_PROPERTY_NAMING = "enumPropertyNaming";
     public static final String ENUM_PROPERTY_NAMING_DESC = "Naming convention for enum properties: 'camelCase', 'PascalCase', 'snake_case', 'UPPERCASE', and 'original'";
 
+    // Allow different language generators to offer an option of serialization library. Each language specific
+    // Codegen constants should define a description and provide proper input validation for the value of serializationLibrary
     public static final String SERIALIZATION_LIBRARY = "serializationLibrary";
-    public static final String SERIALIZATION_LIBRARY_DESC = "What serialization library to use: 'moshi' (default), or 'gson'";
-    public static enum SERIALIZATION_LIBRARY_TYPE {moshi, gson}
 
     public static final String MODEL_NAME_PREFIX = "modelNamePrefix";
     public static final String MODEL_NAME_PREFIX_DESC = "Prefix that will be prepended to all model names.";

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java

@@ -35,6 +35,10 @@
 import static org.openapitools.codegen.utils.StringUtils.*;
 
 public abstract class AbstractKotlinCodegen extends DefaultCodegen implements CodegenConfig {
+
+    public static final String SERIALIZATION_LIBRARY_DESC = "What serialization library to use: 'moshi' (default), or 'gson'";
+    public enum SERIALIZATION_LIBRARY_TYPE {moshi, gson}
+
     private static final Logger LOGGER = LoggerFactory.getLogger(AbstractKotlinCodegen.class);
 
     protected String artifactId;
@@ -51,7 +55,7 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
     protected boolean parcelizeModels = false;
 
     protected CodegenConstants.ENUM_PROPERTY_NAMING_TYPE enumPropertyNaming = CodegenConstants.ENUM_PROPERTY_NAMING_TYPE.camelCase;
-    protected CodegenConstants.SERIALIZATION_LIBRARY_TYPE serializationLibrary = CodegenConstants.SERIALIZATION_LIBRARY_TYPE.moshi;
+    protected SERIALIZATION_LIBRARY_TYPE serializationLibrary = SERIALIZATION_LIBRARY_TYPE.moshi;
 
     public AbstractKotlinCodegen() {
         super();
@@ -207,7 +211,7 @@ public AbstractKotlinCodegen() {
         CliOption enumPropertyNamingOpt = new CliOption(CodegenConstants.ENUM_PROPERTY_NAMING, CodegenConstants.ENUM_PROPERTY_NAMING_DESC);
         cliOptions.add(enumPropertyNamingOpt.defaultValue(enumPropertyNaming.name()));
 
-        CliOption serializationLibraryOpt = new CliOption(CodegenConstants.SERIALIZATION_LIBRARY, CodegenConstants.SERIALIZATION_LIBRARY_DESC);
+        CliOption serializationLibraryOpt = new CliOption(CodegenConstants.SERIALIZATION_LIBRARY, SERIALIZATION_LIBRARY_DESC);
         cliOptions.add(serializationLibraryOpt.defaultValue(serializationLibrary.name()));
 
         cliOptions.add(new CliOption(CodegenConstants.PARCELIZE_MODELS, CodegenConstants.PARCELIZE_MODELS_DESC));
@@ -249,7 +253,7 @@ public CodegenConstants.ENUM_PROPERTY_NAMING_TYPE getEnumPropertyNaming() {
         return this.enumPropertyNaming;
     }
 
-    public CodegenConstants.SERIALIZATION_LIBRARY_TYPE getSerializationLibrary() {
+    public SERIALIZATION_LIBRARY_TYPE getSerializationLibrary() {
         return this.serializationLibrary;
     }
 
@@ -273,14 +277,15 @@ public void setEnumPropertyNaming(final String enumPropertyNamingType) {
     /**
      * Sets the serialization engine for Kotlin
      *
-     * @param enumSerializationLibrary The string representation of the serialization library as defined by {@link org.openapitools.codegen.CodegenConstants.SERIALIZATION_LIBRARY_TYPE}
+     * @param enumSerializationLibrary The string representation of the serialization library as defined by
+     * {@link org.openapitools.codegen.languages.AbstractKotlinCodegen.SERIALIZATION_LIBRARY_TYPE}
      */
     public void setSerializationLibrary(final String enumSerializationLibrary) {
         try {
-            this.serializationLibrary = CodegenConstants.SERIALIZATION_LIBRARY_TYPE.valueOf(enumSerializationLibrary);
+            this.serializationLibrary = SERIALIZATION_LIBRARY_TYPE.valueOf(enumSerializationLibrary);
         } catch (IllegalArgumentException ex) {
             StringBuilder sb = new StringBuilder(enumSerializationLibrary + " is an invalid enum property naming option. Please choose from:");
-            for (CodegenConstants.SERIALIZATION_LIBRARY_TYPE t : CodegenConstants.SERIALIZATION_LIBRARY_TYPE.values()) {
+            for (SERIALIZATION_LIBRARY_TYPE t : SERIALIZATION_LIBRARY_TYPE.values()) {
                 sb.append("\n  ").append(t.name());
             }
             throw new RuntimeException(sb.toString());