fix issue 804 - java discriminator mapping

Author: OsztosA

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

@@ -2,6 +2,6 @@
 @JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "{{discriminator.propertyName}}", visible = true )
 @JsonSubTypes({
   {{#children}}
-  @JsonSubTypes.Type(value = {{classname}}.class, name = "{{^vendorExtensions.x-discriminator-value}}{{name}}{{/vendorExtensions.x-discriminator-value}}{{#vendorExtensions.x-discriminator-value}}{{{vendorExtensions.x-discriminator-value}}}{{/vendorExtensions.x-discriminator-value}}"),
+  @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}}
 }){{/jackson}}

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

@@ -93,4 +93,51 @@ public void interfaceWithCustomDiscriminator() throws Exception {
 
         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/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