JAXB: XmlAdapter для карты с коллекцией в качестве значений

Question

У меня есть класс Container с атрибутом Map. Map имеет Object s в качестве ключа, здесь Double для MWE и связанный Collection в качестве значений, здесь Collection<String> для MWE.

Я пытался маршаллировать Container и написал XmlAdapter работающую реализацию, вдохновленную этой веткой . Тем не менее, я не очень доволен результатом.

Я получаю

<container>
  <results>
    <loadSteps loadStep="1.0">
      <results>
        <result>result1-1</result>
        <result>result1-2</result>
        <result>result1-3</result>
      </results>
    </loadSteps>
    <loadSteps loadStep="2.0">
      <results>
        <result>result2-1</result>
        <result>result2-2</result>
      </results>
    </loadSteps>
  </results>
</container>

Я бы хотел получить

<container>
  <results>
    <loadStep="1.0">
      <result>result1-1</result>
      <result>result1-2</result>
      <result>result1-3</result>
    </loadStep>
    <loadStep="2.0">
      <result>result2-1</result>
      <result>result2-2</result>
    </loadStep>
  </results>

или подобное. Поэтому я хочу, чтобы loadStep был прямым ключом, без loadSteps, распаковывая List in ResultMapType

Это возможно?

С моей попыткой ничего не написано в results/.

---

MWE

• Основной

  public static void main(String[] args) 
          throws 
              FileNotFoundException
             ,JAXBException
             ,ParserConfigurationException
             ,TransformerException
  {
  
      double step1 = 1.0;
      ArrayList<String> step1Result = new ArrayList<>(3);
      step1Result.add("result1-1");
      step1Result.add("result1-2");
      step1Result.add("result1-3");
  
      double step2 = 2.0;
      ArrayList<String> step2Result = new ArrayList<>(3);
      step2Result.add("result2-1");
      step2Result.add("result2-2");
  
      TreeMap<Double,ArrayList<String>> results = new TreeMap<>();
      results.put(step1,step1Result);
      results.put(step2,step2Result);
  
      Container container = new Container();
      container.setResults(results);
  
      // JAXB object
      Object jaxbElement = container;
  
      File file = new File("./container.xml");
      FileOutputStream fop = new FileOutputStream(file);
  
      // create JAXB context
      JAXBContext context = JAXBContext.newInstance(jaxbElement.getClass());
  
      // Creating the Document object
      DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
      DocumentBuilder db = dbf.newDocumentBuilder();
      Document document = db.newDocument();
  
      // Marshaling the User object into a Document object
      Marshaller m = context.createMarshaller();
      m.marshal(jaxbElement, document);
  
      // writing the Document object to console
      TransformerFactory tf = TransformerFactory.newInstance();
      Transformer transformer = tf.newTransformer();
  
      // set the properties for a formatted output - if false the output will be on one single line
      transformer.setOutputProperty(OutputKeys.INDENT, "yes");
      transformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
  
      DOMSource source = new DOMSource(document);
      StreamResult result = new StreamResult(fop);
      transformer.transform(source, result);
  }
  

• Контейнер

  @XmlRootElement
  @XmlAccessorType(XmlAccessType.FIELD)
  public class Container {
  
      @XmlJavaTypeAdapter(ContainerMapAdapter.class)
      private TreeMap<Double,ArrayList<String>> results;
  
      public void setResults(TreeMap<Double,ArrayList<String>> v){this.results = v;}
      public TreeMap<Double,ArrayList<String>> getResults(){return results;}
  
  }
  

• ContainerMapAdapter

  public class ContainerMapAdapter
              extends
                  XmlAdapter<
                      ContainerMapAdapter.ResultMapType
                     ,Map<
                          Double
                         ,ArrayList<String>
                      >
                  >
  {
  
      @Override
      public ResultMapType marshal(Map<Double, ArrayList<String>> map) throws Exception {
          ResultMapType fbmt = new ResultMapType();
          for (Map.Entry<Double, ArrayList<String>> e : map.entrySet()) {
              ResultMapEntry entry = new ResultMapEntry();
              entry.setLoadStep(e.getKey());
              entry.setStepResults(e.getValue());
              fbmt.loadSteps.add(entry);
          }
          return fbmt;
      }
  
      @Override
      public Map<Double, ArrayList<String>> unmarshal(ResultMapType fbmt) throws Exception {
          Map<Double, ArrayList<String>> map = new HashMap<>();
          for (ResultMapEntry entry : fbmt.loadSteps) {
              map.put(entry.getLoadStep(), entry.getStepResults());
          }
          return map;
      }
  
      public static class ResultMapType {
          public List<ResultMapEntry> loadSteps = new ArrayList<>();
      }
  
      @XmlAccessorType(XmlAccessType.NONE)
      public static class ResultMapEntry {
  
          private Double step;
          private ArrayList<String> stepResults;
  
          public void setLoadStep(Double v) {this.step = v;}
          @XmlAttribute
          public Double getLoadStep() {return step;}
  
          public void setStepResults(ArrayList<String> v) {this.stepResults = v;}
  
          @XmlElementWrapper(name="results")
          @XmlElement(name="result")
          public ArrayList<String> getStepResults() {return stepResults;}
  
      }
  
  }
  

---

Попытка

    public class ContainerMapAdapter2
                extends
                    XmlAdapter<
                        ArrayList<ResultMapEntry>
                       ,Map<
                            Double
                           ,ArrayList<String>
                        >
                    >
    {

        @Override
        public ArrayList<ResultMapEntry> marshal(Map<Double, ArrayList<String>> map) throws Exception {
            ArrayList<ResultMapEntry> list = new ArrayList<>(map.size());
            for (Map.Entry<Double, ArrayList<String>> e : map.entrySet()) {
                ResultMapEntry entry = new ResultMapEntry();
                entry.setLoadStep(e.getKey());
                entry.setStepResults(e.getValue());
                list.add(entry);
            }
            return list;
        }

        @Override
        public Map<Double, ArrayList<String>> unmarshal(ArrayList<ResultMapEntry> fbmt) throws Exception {
            Map<Double, ArrayList<String>> map = new HashMap<>();
            for (ResultMapEntry entry : fbmt) {
                map.put(entry.getLoadStep(), entry.getStepResults());
            }
            return map;
        }

        @XmlAccessorType(XmlAccessType.NONE)
        public static class ResultMapEntry {

            private Double step;
            private ArrayList<String> stepResults;

            public void setLoadStep(Double v) {this.step = v;}
            @XmlAttribute
            public Double getLoadStep() {return step;}

            public void setStepResults(ArrayList<String> v) {this.stepResults = v;}

            @XmlElementWrapper(name="results")
            @XmlElement(name="result")
            public ArrayList<String> getStepResults() {return stepResults;}

        }

    }