[java-micronaut] Generate visitor for subtypes with a discriminator

bin/configs/java-micronaut-client.yaml

@@ -8,3 +8,4 @@ additionalProperties:
   build: "all"
   test: "spock"
   requiredPropertiesInConstructor: "false"
+  visitable: "true"

docs/generators/java-micronaut-client.md

@@ -73,6 +73,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |title|Client service name| |null|
 |useBeanValidation|Use BeanValidation API annotations| |true|
 |useOptional|Use Optional container for optional parameters| |false|
+|visitable|Generate visitor for subtypes with a discriminator| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
 ## SUPPORTED VENDOR EXTENSIONS

docs/generators/java-micronaut-server.md

@@ -75,6 +75,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |useAuth|Whether to import authorization and to annotate controller methods accordingly| |true|
 |useBeanValidation|Use BeanValidation API annotations| |true|
 |useOptional|Use Optional container for optional parameters| |false|
+|visitable|Generate visitor for subtypes with a discriminator| |false|
 |withXml|whether to include support for application/xml content type and include XML annotations in the model (works with libraries that provide support for JSON and XML)| |false|
 
 ## SUPPORTED VENDOR EXTENSIONS

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

@@ -28,6 +28,7 @@ public abstract class JavaMicronautAbstractCodegen extends AbstractJavaCodegen i
     public static final String OPT_REQUIRED_PROPERTIES_IN_CONSTRUCTOR = "requiredPropertiesInConstructor";
     public static final String OPT_MICRONAUT_VERSION = "micronautVersion";
     public static final String OPT_USE_AUTH = "useAuth";
+    public static final String OPT_VISITABLE = "visitable";
     public static final String OPT_DATE_LIBRARY_JAVA8 = "java8";
     public static final String OPT_DATE_LIBRARY_JAVA8_LOCAL_DATETIME = "java8-localdatetime";
     public static final String OPT_DATE_FORMAT = "dateFormat";
@@ -36,6 +37,7 @@ public abstract class JavaMicronautAbstractCodegen extends AbstractJavaCodegen i
     protected String title;
     protected boolean useBeanValidation;
     protected boolean useOptional;
+    protected boolean visitable;
     protected String buildTool;
     protected String testTool;
     protected boolean requiredPropertiesInConstructor = true;
@@ -55,6 +57,7 @@ public JavaMicronautAbstractCodegen() {
         // Set all the fields
         useBeanValidation = true;
         useOptional = false;
+        visitable = false;
         buildTool = OPT_BUILD_ALL;
         testTool = OPT_TEST_JUNIT;
         outputFolder = "generated-code/java-micronaut-client";
@@ -99,6 +102,7 @@ public JavaMicronautAbstractCodegen() {
         cliOptions.add(new CliOption(OPT_MICRONAUT_VERSION, "Micronaut version, only >=3.0.0 versions are supported").defaultValue(micronautVersion));
         cliOptions.add(CliOption.newBoolean(USE_BEANVALIDATION, "Use BeanValidation API annotations", useBeanValidation));
         cliOptions.add(CliOption.newBoolean(USE_OPTIONAL, "Use Optional container for optional parameters", useOptional));
+        cliOptions.add(CliOption.newBoolean(OPT_VISITABLE, "Generate visitor for subtypes with a discriminator", visitable));
         cliOptions.add(CliOption.newBoolean(OPT_REQUIRED_PROPERTIES_IN_CONSTRUCTOR, "Allow only to create models with all the required properties provided in constructor", requiredPropertiesInConstructor));
 
         CliOption buildToolOption = new CliOption(OPT_BUILD, "Specify for which build tool to generate files").defaultValue(buildTool);
@@ -167,6 +171,11 @@ public void processOpts() {
         }
         writePropertyBack(USE_OPTIONAL, useOptional);
 
+        if (additionalProperties.containsKey(OPT_VISITABLE)) {
+            this.setVisitable(convertPropertyToBoolean(OPT_VISITABLE));
+        }
+        writePropertyBack(OPT_VISITABLE, visitable);
+
         if (additionalProperties.containsKey(OPT_REQUIRED_PROPERTIES_IN_CONSTRUCTOR)) {
             this.requiredPropertiesInConstructor = convertPropertyToBoolean(OPT_REQUIRED_PROPERTIES_IN_CONSTRUCTOR);
         }
@@ -320,6 +329,10 @@ public void setUseOptional(boolean useOptional) {
         this.useOptional = useOptional;
     }
 
+    public void setVisitable(boolean visitable) {
+        this.visitable = visitable;
+    }
+
     @Override
     public String toApiVarName(String name) {
         String apiVarName = super.toApiVarName(name);
@@ -337,6 +350,10 @@ public boolean isUseOptional() {
         return useOptional;
     }
 
+    public boolean isVisitable() {
+        return visitable;
+    }
+
     @Override
     public OperationsMap postProcessOperationsWithModels(OperationsMap objs, List<ModelMap> allModels) {
         objs = super.postProcessOperationsWithModels(objs, allModels);

modules/openapi-generator/src/main/resources/java-micronaut/common/model/pojo.mustache

@@ -355,4 +355,36 @@ Declare the class with extends and implements
         }
     };
     {{/parcelableModel}}
+    {{#visitable}}
+    {{#discriminator}}
+    /**
+     * Accept the visitor and invoke it for the specific {{classname}} type.
+     *
+     * @param visitor the {{classname}} visitor
+     * @param <T> the return type of the visitor
+     * @return the result from the visitor
+     */
+    public abstract <T> T accept(Visitor<T> visitor);
+
+    /**
+     * A {{classname}} visitor implementation allows visiting the various {{classname}} types.
+     *
+     * @param <R> the return type of the visitor
+     */
+    public interface Visitor<R> {
+        {{#discriminator.mappedModels}}
+        R visit{{modelName}}({{modelName}} value);
+        {{/discriminator.mappedModels}}
+    }
+
+    {{/discriminator}}
+    {{#parent}}
+        {{#interfaces.0}}
+    @Override
+    public <T> T accept({{{parent}}}.Visitor<T> visitor) {
+        return visitor.visit{{classname}}(this);
+    }
+        {{/interfaces.0}}
+    {{/parent}}
+    {{/visitable}}
 }

samples/client/petstore/java-micronaut-client/src/main/java/org/openapitools/model/Animal.java

@@ -141,4 +141,24 @@ private String toIndentedString(Object o) {
         return o.toString().replace("\n", "\n    ");
     }
 
+    /**
+     * Accept the visitor and invoke it for the specific Animal type.
+     *
+     * @param visitor the Animal visitor
+     * @param <T> the return type of the visitor
+     * @return the result from the visitor
+     */
+    public abstract <T> T accept(Visitor<T> visitor);
+
+    /**
+     * A Animal visitor implementation allows visiting the various Animal types.
+     *
+     * @param <R> the return type of the visitor
+     */
+    public interface Visitor<R> {
+        R visitBigCat(BigCat value);
+        R visitCat(Cat value);
+        R visitDog(Dog value);
+    }
+
 }

samples/client/petstore/java-micronaut-client/src/main/java/org/openapitools/model/BigCat.java

@@ -138,4 +138,8 @@ private String toIndentedString(Object o) {
         return o.toString().replace("\n", "\n    ");
     }
 
+    @Override
+    public <T> T accept(Cat.Visitor<T> visitor) {
+        return visitor.visitBigCat(this);
+    }
 }

samples/client/petstore/java-micronaut-client/src/main/java/org/openapitools/model/Cat.java

@@ -103,4 +103,8 @@ private String toIndentedString(Object o) {
         return o.toString().replace("\n", "\n    ");
     }
 
+    @Override
+    public <T> T accept(Animal.Visitor<T> visitor) {
+        return visitor.visitCat(this);
+    }
 }

samples/client/petstore/java-micronaut-client/src/main/java/org/openapitools/model/Dog.java

@@ -103,4 +103,8 @@ private String toIndentedString(Object o) {
         return o.toString().replace("\n", "\n    ");
     }
 
+    @Override
+    public <T> T accept(Animal.Visitor<T> visitor) {
+        return visitor.visitDog(this);
+    }
 }