java interface discriminator mapping

src/main/java/io/swagger/codegen/v3/generators/DefaultCodegenConfig.java

@@ -99,16 +99,8 @@
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
-import static io.swagger.codegen.v3.CodegenConstants.HAS_ONLY_READ_ONLY_EXT_NAME;
-import static io.swagger.codegen.v3.CodegenConstants.HAS_OPTIONAL_EXT_NAME;
-import static io.swagger.codegen.v3.CodegenConstants.HAS_REQUIRED_EXT_NAME;
-import static io.swagger.codegen.v3.CodegenConstants.IS_ARRAY_MODEL_EXT_NAME;
-import static io.swagger.codegen.v3.CodegenConstants.IS_CONTAINER_EXT_NAME;
-import static io.swagger.codegen.v3.CodegenConstants.IS_ENUM_EXT_NAME;
-import static io.swagger.codegen.v3.generators.CodegenHelper.getDefaultIncludes;
-import static io.swagger.codegen.v3.generators.CodegenHelper.getImportMappings;
-import static io.swagger.codegen.v3.generators.CodegenHelper.getTypeMappings;
-import static io.swagger.codegen.v3.generators.CodegenHelper.initalizeSpecialCharacterMapping;
+import static io.swagger.codegen.v3.CodegenConstants.*;
+import static io.swagger.codegen.v3.generators.CodegenHelper.*;
 import static io.swagger.codegen.v3.generators.handlebars.ExtensionHelper.getBooleanValue;
 
 public abstract class DefaultCodegenConfig implements CodegenConfig {
@@ -1344,9 +1336,6 @@ public CodegenModel fromModel(String name, Schema schema, Map<String, Schema> al
         codegenModel.getVendorExtensions().put(CodegenConstants.IS_ALIAS_EXT_NAME, typeAliases.containsKey(name));
 
         codegenModel.discriminator = schema.getDiscriminator();
-        if (codegenModel.discriminator != null && codegenModel.discriminator.getPropertyName() != null) {
-            codegenModel.discriminator.setPropertyName(toVarName(codegenModel.discriminator.getPropertyName()));
-        }
 
         if (schema.getXml() != null) {
             codegenModel.xmlPrefix = schema.getXml().getPrefix();
@@ -1397,6 +1386,25 @@ else if (schema instanceof ComposedSchema) {
                         }
                     }
                 }
+                if (codegenModel.discriminator != null && codegenModel.discriminator.getPropertyName() != null) {
+                    codegenModel.discriminator.setPropertyName(toVarName(codegenModel.discriminator.getPropertyName()));
+                    Map<String, String> classnameKeys = new HashMap<>();
+
+                    if (composed.getOneOf()!=null) {
+                        composed.getOneOf().forEach( s -> {
+                            codegenModel.discriminator.getMapping().keySet().stream().filter( key -> codegenModel.discriminator.getMapping().get(key).equals(s.get$ref()))
+                                .forEach(key -> {
+                                    String mappingValue = codegenModel.discriminator.getMapping().get(key);
+                                    if (classnameKeys.containsKey(codegenModel.classname)) {
+                                        throw new IllegalArgumentException("Duplicate shema name in discriminator mapping");
+                                    }
+                                    classnameKeys.put(toModelName(mappingValue.replace("#/components/schemas/", "")),key);
+                                });
+                        });
+                        codegenModel.discriminator.getMapping().putAll(classnameKeys);
+                    }
+                }
+
             } else {
                 allProperties = null;
                 allRequired = null;
@@ -4415,7 +4423,7 @@ protected void setParameterJson(CodegenParameter codegenParameter, Schema parame
             codegenParameter.isJson = true;
         }
     }
-  
+
     protected boolean isFileTypeSchema(Schema schema) {
         final Schema fileTypeSchema;
         if (StringUtils.isNotBlank(schema.get$ref())) {

src/main/java/io/swagger/codegen/v3/generators/SchemaHandler.java

@@ -199,9 +199,7 @@ protected void addInterfaces(List<Schema> schemas, CodegenModel codegenModel, Ma
                 codegenModel.addSubType(model);
             }
 
-            if (codegenModel.getVendorExtensions() == null || codegenModel.getVendorExtensions().containsKey("x-discriminator-type")) {
-                continue;
-            }
+
             if (codegenModel.getDiscriminator() != null && StringUtils.isNotBlank(codegenModel.getDiscriminator().getPropertyName())) {
                 Optional<CodegenProperty> optionalProperty = model.vars.stream()
                     .filter(codegenProperty -> codegenProperty.baseName.equals(codegenModel.getDiscriminator().getPropertyName())).findFirst();

src/main/resources/handlebars/Java/interface.mustache

@@ -9,10 +9,10 @@ import com.fasterxml.jackson.annotation.JsonTypeInfo;
 @JsonTypeInfo(
   use = JsonTypeInfo.Id.NAME,
   include = JsonTypeInfo.As.PROPERTY,
-  property = "type")
+  property = "{{discriminator.propertyName}}")
 @JsonSubTypes({
   {{#subTypes}}
-  @JsonSubTypes.Type(value = {{classname}}.class, name = "{{classname}}"){{^@last}},{{/@last}}
+  @JsonSubTypes.Type(value = {{classname}}.class, name = "{{subtypeName}}"){{^@last}},{{/@last}}
   {{/subTypes}}
 })
 {{/jackson}}

src/main/resources/handlebars/Java/typeInfoAnnotation.mustache

@@ -1,14 +1,8 @@
 {{#jackson}}
 @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "{{discriminator.propertyName}}", visible = true )
 @JsonSubTypes({
-{{#if discriminator.mapping}}
-{{#each discriminator.mapping}}
-  @JsonSubTypes.Type(value = {{this}}.class, name = "{{@key}}"),
-{{/each}}
-{{else}}
 {{#children}}
-  @JsonSubTypes.Type(value = {{classname}}.class, name = "{{name}}"),
+  @JsonSubTypes.Type(value = {{classname}}.class, name = "{{^vendorExtensions.x-discriminator-value}}{{subtypeName}}{{/vendorExtensions.x-discriminator-value}}{{#vendorExtensions.x-discriminator-value}}{{{vendorExtensions.x-discriminator-value}}}{{/vendorExtensions.x-discriminator-value}}"),
 {{/children}}
-{{/if}}
 })
-{{/jackson}}
+{{/jackson}}

src/test/java/io/swagger/codegen/v3/generators/GeneratorRunner.java

@@ -13,6 +13,8 @@
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.util.List;
+import java.util.function.Consumer;
+import java.util.function.Supplier;
 
 /**
  *
@@ -28,14 +30,22 @@ public static List<File> runGenerator(
         boolean v2Spec,
         boolean yaml,
         boolean flattenInlineComposedSchema,
-        String outFolder
+        String outFolder,
+        Consumer<Options> optionsCustomizer
     ) throws Exception {
 
         String path = outFolder;
         if (StringUtils.isBlank(path)) {
             path = getTmpFolder().getAbsolutePath();
         }
         GenerationRequest request = new GenerationRequest();
+
+        Options option = new Options()
+            .flattenInlineComposedSchema(flattenInlineComposedSchema)
+            .outputDir(path);
+
+        optionsCustomizer.accept(option);
+
         request
             .codegenVersion(codegenVersion) // use V2 to target Swagger/OpenAPI 2.x Codegen version
             .type(GenerationRequest.Type.CLIENT)
@@ -44,9 +54,7 @@ public static List<File> runGenerator(
                 yaml, // YAML file, use false for JSON
                 v2Spec)) // OpenAPI 3.x - use true for Swagger/OpenAPI 2.x definitions
             .options(
-                new Options()
-                    .flattenInlineComposedSchema(flattenInlineComposedSchema)
-                    .outputDir(path)
+                option
             );
 
         List<File> files = new GeneratorService().generationRequest(request).generate();

src/test/java/io/swagger/codegen/v3/generators/java/GeneratorResultTestJava.java

@@ -1,12 +1,18 @@
 package io.swagger.codegen.v3.generators.java;
 
+import com.fasterxml.jackson.annotation.JsonSubTypes;
 import io.swagger.codegen.v3.generators.GeneratorRunner;
 import io.swagger.codegen.v3.service.GenerationRequest;
+import org.apache.commons.io.FileUtils;
 import org.testng.Assert;
 import org.testng.annotations.Test;
 
 import java.io.File;
+import java.nio.file.Files;
+import java.nio.file.Paths;
 import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 public class GeneratorResultTestJava {
 
@@ -29,11 +35,109 @@ public void testJavaGenerator_OneOf() throws Exception {
             v2Spec,
             yaml,
             flattenInlineComposedSchema,
-            outFolder);
+            outFolder, options -> {});
 
         Assert.assertFalse(files.isEmpty());
         for (File f: files) {
             // TODO test stuff
         }
     }
+
+    @Test
+    public void interfaceWithCustomDiscriminator() throws Exception {
+
+        String name = "java";
+        String specPath = "3_0_0/sample_interface_with_discriminator.json";
+        GenerationRequest.CodegenVersion codegenVersion = GenerationRequest.CodegenVersion.V3;
+        boolean v2Spec = false; // 3.0 spec
+        boolean yaml = false;
+        boolean flattenInlineComposedSchema = true;
+        String outFolder = null; // temporary folder
+
+        File tmpFolder = GeneratorRunner.getTmpFolder();
+        Assert.assertNotNull(tmpFolder);
+
+        List<File> files = GeneratorRunner.runGenerator(
+            name,
+            specPath,
+            codegenVersion,
+            v2Spec,
+            yaml,
+            flattenInlineComposedSchema,
+            tmpFolder.getAbsolutePath(),
+            options -> options.setLibrary("resttemplate"));
+
+
+        File interfaceFile = files.stream().filter(f -> f.getName().equals("Item.java")).findAny().orElseThrow(() -> new RuntimeException("No interface generated"));
+
+        String interfaceContent = new String(Files.readAllBytes(Paths.get(interfaceFile.toURI())));
+
+        Pattern typeInfoPattern = Pattern.compile("(.*)(@JsonTypeInfo\\()(.*)(}\\))(.*)", Pattern.DOTALL);
+
+        Matcher matcher = typeInfoPattern.matcher(interfaceContent);
+
+        Assert.assertTrue(matcher.matches(),
+            "No JsonTypeInfo generated into the interface file");
+
+        String generatedTypeInfoLines = matcher.group(2)+matcher.group(3)+matcher.group(4);
+
+        Assert.assertEquals( generatedTypeInfoLines, "@JsonTypeInfo(" + System.lineSeparator() +
+            "  use = JsonTypeInfo.Id.NAME," + System.lineSeparator() +
+            "  include = JsonTypeInfo.As.PROPERTY," + System.lineSeparator() +
+            "  property = \"aCustomProperty\")" + System.lineSeparator() +
+            "@JsonSubTypes({" + System.lineSeparator() +
+            "  @JsonSubTypes.Type(value = ClassA.class, name = \"typeA\")," + System.lineSeparator() +
+            "  @JsonSubTypes.Type(value = ClassB.class, name = \"typeB\")," + System.lineSeparator() +
+            "  @JsonSubTypes.Type(value = ClassC.class, name = \"typeC\")" + System.lineSeparator() +
+            "})", "Wrong json subtypes generated");
+
+        FileUtils.deleteDirectory(new File(tmpFolder.getAbsolutePath()));
+    }
+
+    @Test
+    public void javaCustomDiscriminator() throws Exception {
+
+        String name = "java";
+        String specPath = "3_0_0/javaDiscriminatorExample.yaml";
+        GenerationRequest.CodegenVersion codegenVersion = GenerationRequest.CodegenVersion.V3;
+        boolean v2Spec = false; // 3.0 spec
+        boolean yaml = true;
+        boolean flattenInlineComposedSchema = true;
+        String outFolder = null; // temporary folder
+
+        File tmpFolder = GeneratorRunner.getTmpFolder();
+        Assert.assertNotNull(tmpFolder);
+
+        List<File> files = GeneratorRunner.runGenerator(
+            name,
+            specPath,
+            codegenVersion,
+            v2Spec,
+            yaml,
+            flattenInlineComposedSchema,
+            tmpFolder.getAbsolutePath(),
+            options -> options.setLibrary("resttemplate"));
+
+
+        File interfaceFile = files.stream().filter(f -> f.getName().equals("ResultForSubTypeDTO.java")).findAny().orElseThrow(() -> new RuntimeException("No class generated"));
+
+        String interfaceContent = new String(Files.readAllBytes(Paths.get(interfaceFile.toURI())));
+
+        Pattern typeInfoPattern = Pattern.compile("(.*)(@JsonTypeInfo\\()(.*)(}\\))(.*)", Pattern.DOTALL);
+
+        Matcher matcher = typeInfoPattern.matcher(interfaceContent);
+
+        Assert.assertTrue(matcher.matches(),
+            "No JsonTypeInfo generated into the interface file");
+
+        String generatedTypeInfoLines = matcher.group(2)+matcher.group(3)+matcher.group(4);
+
+        Assert.assertEquals( generatedTypeInfoLines, "@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = \"type\", visible = true )" + System.lineSeparator() +
+            "@JsonSubTypes({" + System.lineSeparator() +
+            "  @JsonSubTypes.Type(value = SubTypeBResultDTO.class, name = \"WeirdlyNamedSubTypeB\")," + System.lineSeparator() +
+            "  @JsonSubTypes.Type(value = SubTypeAResultDTO.class, name = \"SubTypeA\")," + System.lineSeparator() +
+            "})");
+
+        FileUtils.deleteDirectory(new File(tmpFolder.getAbsolutePath()));
+    }
 }

src/test/java/io/swagger/codegen/v3/generators/java/JavaPolymorphicAnnotationCodegenTest.java

@@ -31,10 +31,10 @@ public void testParameterOrders() throws Exception {
         final String content = FileUtils.readFileToString(petControllerFile);
 
         Assert.assertTrue(content.contains(
-            "@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = \"type\", visible = true )\n" +
-                "@JsonSubTypes({\n" +
-                "        @JsonSubTypes.Type(value = Error.class, name = \"Error\"),\n" +
-                "        @JsonSubTypes.Type(value = Success.class, name = \"Success\"),\n" +
+            "@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = \"type\", visible = true )" + System.lineSeparator() +
+                "@JsonSubTypes({" + System.lineSeparator() +
+                "        @JsonSubTypes.Type(value = Error.class, name = \"Error\")," + System.lineSeparator() +
+                "        @JsonSubTypes.Type(value = Success.class, name = \"Success\")," + System.lineSeparator() +
                 "})"));
 
         this.folder.delete();

src/test/resources/3_0_0/javaDiscriminatorExample.yaml

@@ -0,0 +1,52 @@
+openapi: '3.0.3'
+info:
+  title: 'Discriminator Problem API'
+  version: '1.0.0'
+
+components:
+  schemas:
+    SomeTypeDTO:
+      type: string
+      enum:
+        - SubTypeA
+        - WeirdlyNamedSubTypeB
+
+    ResultForSubTypeDTO:
+      type: object
+      properties:
+        type:
+          type: string
+      oneOf:
+        - $ref: '#/components/schemas/SubTypeAResultDTO'
+        - $ref: '#/components/schemas/SubTypeBResultDTO'
+      required:
+        - type
+      discriminator:
+        propertyName: type
+        mapping:
+          SubTypeA: '#/components/schemas/SubTypeAResultDTO'
+          WeirdlyNamedSubTypeB: '#/components/schemas/SubTypeBResultDTO'
+
+    SubTypeAResultDTO:
+      allOf:
+        - $ref: '#/components/schemas/ResultForSubTypeDTO'
+      type: object
+      properties:
+        some_attribute:
+          type: string
+
+    SubTypeBResultDTO:
+      allOf:
+        - $ref: '#/components/schemas/ResultForSubTypeDTO'
+      type: object
+      properties:
+        another_attribute:
+          type: string
+
+paths:
+  /repro:
+    get:
+      operationId: 'getRepo'
+      responses:
+        204:
+          description: OK