[Java] Fix content for enum in MultiPart (#19973)

.github/workflows/samples-java-client-jdk17.yaml

@@ -7,12 +7,14 @@ on:
       - samples/client/petstore/java/webclient-jakarta/**
       - samples/client/petstore/java/restclient-*/**
       - samples/client/petstore/java/webclient-useSingleRequestParameter/**
+      - samples/client/others/java/restclient-enum-in-multipart/**
   pull_request:
     paths:
       - samples/client/petstore/java/resttemplate-jakarta/**
       - samples/client/petstore/java/webclient-jakarta/**
       - samples/client/petstore/java/restclient-*/**
       - samples/client/petstore/java/webclient-useSingleRequestParameter/**
+      - samples/client/others/java/restclient-enum-in-multipart/**
 jobs:
   build:
     name: Build Java Client JDK17
@@ -30,6 +32,7 @@ jobs:
           - samples/client/petstore/java/restclient-useSingleRequestParameter
           - samples/client/petstore/java/restclient-useSingleRequestParameter-static
           - samples/client/petstore/java/webclient-useSingleRequestParameter
+          - samples/client/others/java/restclient-enum-in-multipart
     steps:
       - uses: actions/checkout@v4
       - uses: actions/setup-java@v4

bin/configs/java-restclient-enum-in-multipart.yaml

@@ -0,0 +1,7 @@
+generatorName: java
+outputDir: samples/client/others/java/restclient-enum-in-multipart
+library: restclient
+inputSpec: modules/openapi-generator/src/test/resources/3_1/enum-in-multipart.yaml
+templateDir: modules/openapi-generator/src/main/resources/Java
+additionalProperties:
+  hideGenerationTimestamp: "true"

modules/openapi-generator/src/main/resources/Java/libraries/restclient/ApiClient.mustache

@@ -685,6 +685,18 @@ public class ApiClient{{#jsr310}} extends JavaTimeFormatter{{/jsr310}} {
         addCookiesToRequest(cookieParams, requestBuilder);
         addCookiesToRequest(defaultCookies, requestBuilder);
 
+        if (MediaType.MULTIPART_FORM_DATA.isCompatibleWith(contentType)) {
+            formParams.forEach(
+                    (k, v) -> {
+                        if (v instanceof java.util.ArrayList) {
+                            Object o = v.get(0);
+                            if (o != null && o.getClass().getEnumConstants() != null) {
+                                v.set(0, o.toString());
+                            }
+                        }
+                    });
+        }
+
         var selectedBody = selectBody(body, formParams, contentType);
         if (selectedBody != null) {
           requestBuilder.body(selectedBody);

modules/openapi-generator/src/test/resources/3_1/enum-in-multipart.yaml

@@ -0,0 +1,105 @@
+openapi: 3.1.0
+info:
+  description: API
+  title: API
+  version: 1.0.0
+servers:
+- description: "Localhost, used when testing"
+  url: http://localhost:8080
+security:
+- basicAuth: []
+paths:
+  /messages:
+    post:
+      description: Creates a new message
+      x-content-type: multipart/form-data
+      x-accepts:
+      - application/json
+      operationId: CreateMessage
+      requestBody:
+        $ref: "#/components/requestBodies/CreateMessageBody"
+      responses:
+        "201":
+          $ref: "#/components/responses/MessageCreatedResponse"
+      summary: Creates a new message
+      tags:
+      - BAS
+components:
+  parameters:
+    messageId:
+      description: The identifier the message
+      explode: false
+      in: path
+      name: messageId
+      required: true
+      schema:
+        format: uuid
+        type: string
+      style: simple
+  requestBodies:
+    CreateMessageBody:
+      content:
+        multipart/form-data:
+          schema:
+            $ref: "#/components/schemas/CreateMessage_request"
+      required: true
+  responses:
+    MessageCreatedResponse:
+      content:
+        application/json:
+          schema:
+            $ref: "#/components/schemas/inline_object"
+      description: The message was created.
+  schemas:
+    DataDirection:
+      description: The direction a message travels
+      enum:
+      - INGOING
+      - OUTGOING
+      type: string
+    DataChannel:
+      description: The transport-channel
+      enum:
+      - BIKE
+      - CAR
+      - BUS
+      - PLANE
+      type: string
+    messageId:
+      description: The messageID
+      format: uuid
+      type: string
+    CreateMessage_request:
+      properties:
+        fileContent:
+          description: The message payload
+          format: binary
+          type: string
+        idempotencyKey:
+          type: string
+        dataDirection:
+          $ref: "#/components/schemas/DataDirection"
+        dataChannel:
+          $ref: "#/components/schemas/DataChannel"
+      required:
+      - dataChannel
+      - dataDirection
+      - fileContent
+      - fileType
+      - idempotencyKey
+      type: object
+    inline_object:
+      example:
+        messageId: 046b6c7f-0b8a-43b9-b35d-6489e6daee91
+      properties:
+        messageId:
+          description: The messageID
+          format: uuid
+          type: string
+      required:
+      - messageId
+  securitySchemes:
+    basicAuth:
+      scheme: basic
+      type: http
+

samples/client/echo_api/java/restclient/src/main/java/org/openapitools/client/ApiClient.java

@@ -639,6 +639,18 @@ protected RestClient.RequestBodySpec prepareRequest(String path, HttpMethod meth
         addCookiesToRequest(cookieParams, requestBuilder);
         addCookiesToRequest(defaultCookies, requestBuilder);
 
+        if (MediaType.MULTIPART_FORM_DATA.isCompatibleWith(contentType)) {
+            formParams.forEach(
+                    (k, v) -> {
+                        if (v instanceof java.util.ArrayList) {
+                            Object o = v.get(0);
+                            if (o != null && o.getClass().getEnumConstants() != null) {
+                                v.set(0, o.toString());
+                            }
+                        }
+                    });
+        }
+
         var selectedBody = selectBody(body, formParams, contentType);
         if (selectedBody != null) {
           requestBuilder.body(selectedBody);

samples/client/others/java/restclient-enum-in-multipart/.github/workflows/maven.yml

@@ -0,0 +1,30 @@
+# This workflow will build a Java project with Maven, and cache/restore any dependencies to improve the workflow execution time
+# For more information see: https://help.github.com/actions/language-and-framework-guides/building-and-testing-java-with-maven
+#
+# This file is auto-generated by OpenAPI Generator (https://openapi-generator.tech)
+
+name: Java CI with Maven
+
+on:
+  push:
+    branches: [ main, master ]
+  pull_request:
+    branches: [ main, master ]
+
+jobs:
+  build:
+    name: Build API
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        java: [ 17, 21 ]
+    steps:
+    - uses: actions/checkout@v4
+    - name: Set up JDK
+      uses: actions/setup-java@v4
+      with:
+        java-version: ${{ matrix.java }}
+        distribution: 'temurin'
+        cache: maven
+    - name: Build with Maven
+      run: mvn -B package --no-transfer-progress --file pom.xml

samples/client/others/java/restclient-enum-in-multipart/.gitignore

@@ -0,0 +1,21 @@
+*.class
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.ear
+
+# exclude jar for gradle wrapper
+!gradle/wrapper/*.jar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+# build files
+**/target
+target
+.gradle
+build

samples/client/others/java/restclient-enum-in-multipart/.openapi-generator-ignore

@@ -0,0 +1,23 @@
+# OpenAPI Generator Ignore
+# Generated by openapi-generator https://github.com/openapitools/openapi-generator
+
+# Use this file to prevent files from being overwritten by the generator.
+# The patterns follow closely to .gitignore or .dockerignore.
+
+# As an example, the C# client generator defines ApiClient.cs.
+# You can make changes and tell OpenAPI Generator to ignore just this file by uncommenting the following line:
+#ApiClient.cs
+
+# You can match any string of characters against a directory, file or extension with a single asterisk (*):
+#foo/*/qux
+# The above matches foo/bar/qux and foo/baz/qux, but not foo/bar/baz/qux
+
+# You can recursively match patterns against a directory, file or extension with a double asterisk (**):
+#foo/**/qux
+# This matches foo/bar/qux, foo/baz/qux, and foo/bar/baz/qux
+
+# You can also negate patterns with an exclamation (!).
+# For example, you can ignore all files in a docs folder with the file extension .md:
+#docs/*.md
+# Then explicitly reverse the ignore rule for a single file:
+#!docs/README.md

samples/client/others/java/restclient-enum-in-multipart/.openapi-generator/FILES

@@ -0,0 +1,36 @@
+.github/workflows/maven.yml
+.gitignore
+.travis.yml
+README.md
+api/openapi.yaml
+build.gradle
+build.sbt
+docs/BasApi.md
+docs/DataChannel.md
+docs/DataDirection.md
+docs/InlineObject.md
+git_push.sh
+gradle.properties
+gradle/wrapper/gradle-wrapper.jar
+gradle/wrapper/gradle-wrapper.properties
+gradlew
+gradlew.bat
+pom.xml
+settings.gradle
+src/main/AndroidManifest.xml
+src/main/java/org/openapitools/client/ApiClient.java
+src/main/java/org/openapitools/client/JavaTimeFormatter.java
+src/main/java/org/openapitools/client/RFC3339DateFormat.java
+src/main/java/org/openapitools/client/RFC3339InstantDeserializer.java
+src/main/java/org/openapitools/client/RFC3339JavaTimeModule.java
+src/main/java/org/openapitools/client/ServerConfiguration.java
+src/main/java/org/openapitools/client/ServerVariable.java
+src/main/java/org/openapitools/client/StringUtil.java
+src/main/java/org/openapitools/client/api/BasApi.java
+src/main/java/org/openapitools/client/auth/ApiKeyAuth.java
+src/main/java/org/openapitools/client/auth/Authentication.java
+src/main/java/org/openapitools/client/auth/HttpBasicAuth.java
+src/main/java/org/openapitools/client/auth/HttpBearerAuth.java
+src/main/java/org/openapitools/client/model/DataChannel.java
+src/main/java/org/openapitools/client/model/DataDirection.java
+src/main/java/org/openapitools/client/model/InlineObject.java

samples/client/others/java/restclient-enum-in-multipart/.openapi-generator/VERSION

@@ -0,0 +1 @@
+7.14.0-SNAPSHOT

samples/client/others/java/restclient-enum-in-multipart/.travis.yml

@@ -0,0 +1,22 @@
+#
+# Generated by OpenAPI Generator: https://openapi-generator.tech
+#
+# Ref: https://docs.travis-ci.com/user/languages/java/
+#
+language: java
+jdk:
+  - openjdk12
+  - openjdk11
+  - openjdk10
+  - openjdk9
+  - openjdk8
+before_install:
+  # ensure gradlew has proper permission
+  - chmod a+x ./gradlew
+script:
+  # test using maven
+  #- mvn test
+  # test using gradle
+  - gradle test
+  # test using sbt
+  # - sbt test