Fix issue #2449: SubClass annotations are missing from the base class.

modules/swagger-codegen/src/main/java/io/swagger/codegen/CodegenModel.java

@@ -11,6 +11,7 @@ public class CodegenModel {
     // References to parent and interface CodegenModels. Only set when code generator supports inheritance.
     public CodegenModel parentModel;
     public List<CodegenModel> interfaceModels;
+    public List<CodegenModel> children;
 
     public String name, classname, description, classVarName, modelJson, dataType;
     public String classFilename; // store the class file name, mainly used for import
@@ -26,7 +27,7 @@ public class CodegenModel {
     public Set<String> allMandatory;
 
     public Set<String> imports = new TreeSet<String>();
-    public Boolean hasVars, emptyVars, hasMoreModels, hasEnums, isEnum;
+    public Boolean hasVars, emptyVars, hasMoreModels, hasEnums, isEnum, hasChildren, hasMoreChildren;
     public ExternalDocs externalDocs;
 
     public Map<String, Object> vendorExtensions;

modules/swagger-codegen/src/main/java/io/swagger/codegen/DefaultCodegen.java

@@ -123,6 +123,19 @@ public Map<String, Object> postProcessAllModels(Map<String, Object> objs) {
                     }
                 }
             }
+            // Let parent know about all its children
+            for (String name : allModels.keySet()) {
+                CodegenModel cm = allModels.get(name);
+                if (cm.parent == null) continue;
+                CodegenModel parent = allModels.get(cm.parent);
+                if (parent.children == null) {
+                    parent.children = new ArrayList<CodegenModel>();
+                } else {
+                    parent.children.get(parent.children.size() - 1).hasMoreChildren = Boolean.TRUE; 
+                }
+                parent.children.add(cm);
+                parent.hasChildren = true;
+            }
         }
         return objs;
     }

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

@@ -47,6 +47,7 @@ public class JavaClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     public JavaClientCodegen() {
         super();
+        supportsInheritance = true;
         outputFolder = "generated-code" + File.separator + "java";
         modelTemplateFiles.put("model.mustache", ".java");
         apiTemplateFiles.put("api.mustache", ".java");
@@ -238,6 +239,8 @@ public void processOpts() {
         importMapping.put("ApiModelProperty", "io.swagger.annotations.ApiModelProperty");
         importMapping.put("ApiModel", "io.swagger.annotations.ApiModel");
         importMapping.put("JsonProperty", "com.fasterxml.jackson.annotation.JsonProperty");
+        importMapping.put("JsonSubTypes", "com.fasterxml.jackson.annotation.JsonSubTypes");
+        importMapping.put("JsonTypeInfo", "com.fasterxml.jackson.annotation.JsonTypeInfo");
         importMapping.put("JsonValue", "com.fasterxml.jackson.annotation.JsonValue");
         importMapping.put("Objects", "java.util.Objects");
         importMapping.put("StringUtil", invokerPackage + ".StringUtil");
@@ -542,6 +545,10 @@ public CodegenModel fromModel(String name, Model model, Map<String, Model> allDe
         if(codegenModel.description != null) {
             codegenModel.imports.add("ApiModel");
         }
+        if (codegenModel.discriminator != null) {
+            codegenModel.imports.add("JsonSubTypes");
+            codegenModel.imports.add("JsonTypeInfo");
+        }
         if (allDefinitions != null && codegenModel != null && codegenModel.parentSchema != null && codegenModel.hasEnums) {
             final Model parentModel = allDefinitions.get(codegenModel.parentSchema);
             final CodegenModel parentCodegenModel = super.fromModel(codegenModel.parent, parentModel);

modules/swagger-codegen/src/main/resources/Java/pojo.mustache

@@ -1,5 +1,6 @@
 {{#description}}@ApiModel(description = "{{{description}}}"){{/description}}
 {{>generatedAnnotation}}
+{{#hasChildren}}{{>typeInfoAnnotation}}{{/hasChildren}}
 public class {{classname}} {{#parent}}extends {{{parent}}}{{/parent}} {{#serializableModel}}implements Serializable{{/serializableModel}} {
   {{#vars}}{{#isEnum}}
 

modules/swagger-codegen/src/main/resources/Java/typeInfoAnnotation.mustache

@@ -0,0 +1,6 @@
+@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "{{discriminator}}" )
+@JsonSubTypes({ 
+		{{#children}}@JsonSubTypes.Type(value = {{name}}.class, name = "{{name}}"){{#hasMoreChildren}},
+		{{/hasMoreChildren}}{{/children}}
+})
+