JsonConverter failed with ObservableList

[Tai Hu]

Hi,

    I used RestSource to make RESTful call to my remote web service server. Since the return data is in JSON format, I created a JsonConverter as

JsonConverter<DataModel> jsonConverter = new JsonConverter<DataModel>(DataModel.class);

My DataModel contains a ObservableList<ChildModel>, after I run listDataProvider.retrieve(), an exception throw out from Worker thread

org.codehaus.jackson.map.JsonMappingException: Can not find a deserializer for non-concrete Collection type [collection type; class javafx.collections.ObservableList, contains [simple type, class com.test.model.ChildModel]]

I knew this is more of a Jackson API question. Just want to see if you have a quick solution about this. Since my data model object contains a lot of ObservableList.

Thanks,

Tai

[Johan Vos]

Hi,

Can you use a ListProperty instead?

- Johan

--
You received this message because you are subscribed to the Google Groups "DataFX" group.
To unsubscribe from this group and stop receiving emails from it, send an email to datafx-dev+...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

[Tai Hu]

Johan,

     I just tried ListProperty and it has the same problem with ObservableList, since ListProperty is not a concrete class. If you use SimpleListProperty instead, then it will pass the non-concrete collection type error. However, it runs into a java.lang.UnsupportedOperationException. I looked into JavaFX 8 source code, it turns out that for SimpleListProperty, if you create an instance by using default constructor (no arg constructor), it creates a FXCollections.emptyObservableList(), which is unmodifiable. So for now, I just created my own deserializer then put @JsonDeserialize annotation on my model class to handle ObservableList

Thanks,

Tai

[Hendrik Ebbers]

Hi,
can you share the code with us?

[Tai Hu]

Sure, here is the code I used to handle ObservableList

Model Object

@JsonDeserializer(using=ParentObjectDeserializer.class)

public class ParentObject {

    private String name;

    ObservableList<ChildObject> children;

    // getter and setter

    ...

}

public class ChildObject {

      private String name;

      // getter and setter

      ...

}

Deserializer class

public class ParentObjectDeserializer extends JsonDeserializer<ParentObject> {

     public ParentObjectDeserializer() {

     }

     @Override

     public ParentObject deserialize(JsonParser parser, DeserializationContext ctx)

throws IOException, JsonProcessingException {

            ParentObject parentObject = new ParentObject();

            ObjectMapper objectMapper = (ObjectMapper) parser.getCodec();

            JsonNode node = objectMapper.readTree(parser);

            parent.setName(node.get("name").asText());

            JsonNode childNodes = node.get("children");

            ObservableList<ChildObject> children = FXCollections.observableArrayList();

            for (Iterator<JsonNode> i = childNodes.iterator(); i.hasNext();) {

                  JsonNode childNode = i.next();

                  ChildObject child = new ChildObject();

                  child.setName(childNode.get("name"));

                  children.add(child);

            }

            parentObject.setChildren(children);

            return parentObject;

     }

}

Once you put @JsonDeserializer annotation on your model object, DataFX's JsonConverter (Actually it is Jackson's ObjectMapper) will automatically use your customized deserializer instead of default standard one. I hope that there is a better solution to this issue. With this approach, you need to write a deserializer for every model object which contains a ObservableList.

Tai

[Johan Vos]

Hi Tai,

We are changing the default implementation for the JsonConverter: we now use the javax.json API. This doesn't come with a mapper yet, so we use an own mapper for now (until there is a reference implementation). In the Mapper we are writing, we will make sure that list/arrays are automatically mapped to ObservableList fields. Stay tuned, this shouldn't take long...

- Johan

Op donderdag 29 mei 2014 01:23:49 UTC+2 schreef Tai Hu:

[Johan Vos]

Tai,

I committed the new version of the JsonConverter, and added a sample in org.datafx.samples.NestedListSample.
Is this useful?

- Johan

Op dinsdag 24 juni 2014 13:09:43 UTC+2 schreef Johan Vos:

[Turbo JV]

I did this working when JsonConverter was using jackson.  Now changed it trying to fix my code so works with new JsonConverter

Below is Converter being created

JsonConverter jsonConvert = new JsonConverter("jsonCase", CaseTable.class);

Below is the class trying to create in java

@XmlRootElement(name = "jsonCase")

public class CaseTable {

    

    private final StringProperty caseTitleProp = new SimpleStringProperty();

    private long caseID;

    private String caseTitle;

    public CaseTable() {

        this.caseID = -1;

        this.caseTitle = "";

        caseTitleProp.set("");        

    }    

    

    public CaseTable(long caseID, String caseTitle) {

        this.caseID = caseID;

        this.caseTitle = caseTitle;

        caseTitleProp.set(caseTitle);

    }

    

    public String getCaseTitleProp() {

        return caseTitleProp.get();

    }

    public void setCaseTitleProp(String value) {

        caseTitleProp.set(value);

    }

    public StringProperty caseTitlePropProperty() {

        return caseTitleProp;

    }

    

//    @JsonProperty("CaseID")

    @XmlElement(name = "CaseID")

    public long getCaseID() {

        return caseID;

    }

    public void setCaseID(long caseID) {

        this.caseID = caseID;

    }

//    @JsonProperty("CaseTitle")

    @XmlElement(name = "CaseTitle")

    public String getCaseTitle() {

        return caseTitle;

    }

    public void setCaseTitle(String caseTitle) {

        setCaseTitleProp(caseTitle);

        this.caseTitle = caseTitle;

    }

    

}

Here is json message

{"dsJson":{"jsonCase":[{"CaseID":1,"CaseTitle":"Case 1"},{"CaseID":2,"CaseTitle":"Case 2"}]}}

Can you see anything I am doing wrong.  Or is there bug is system?

Kind Regards,

TurboJV

[Turbo JV]

I have change server so json message is as follows and now working.

{"jsonCase":[{"CaseID":1,"CaseTitle":"Case 1"},{"CaseID":2,"CaseTitle":"Case 2"}]}


Seems like there is bug where can not find nested json Arrays.  Was working with jackson converter.

Kind Regards,

TurboJV