Flexjson - how to serialize a complex hierarchy including a Map

Question

Using Flexjson, I am trying to serialize an object ("Payload") that contains a List. Each MyBean has a field "items", which is a Map>. When I serialize this Payload object, the map field ("items") is empty.

public class Payload {

private List<MyBean> myBeans = new ArrayList<MyBean>();

//the JSON returned has blank values for myBeans.values.items
public String toJson() {
        return new JSONSerializer()
            .exclude("*.class")
            .include("myBeans")
            .serialize(this);
}

}

However, when I serialize the MyBean object directly, it works fine.

public class MyBean {

private Map<String, List<SomeBean>> items = new HashMap<String, List<SomeBean>>();

//this works
public String toJson() {
        return new JSONSerializer()
            .exclude("*.class")
            .deepSerialize(this);
}

}

Any suggestions?

Answer 1

After trying a bunch of things, I found this solution. I created a custom transformer for maps. Just copied the Flexjson MapTransformer and commented out a IF condition. New code below

public class Payload {

    private List<MyBean> myBeans = new ArrayList<MyBean>();

    //the JSON returned has blank values for myBeans.values.items
    public String toJson() {
            return new JSONSerializer()
                .exclude("*.class")
                .include("myBeans")
                .transform(new SOMapTransformer(), Map.class)
                .serialize(this);
    }
}


public class MyBean {

    private Map<String, List<SomeBean>> items = new HashMap<String, List<SomeBean>>();

    //this works
    public String toJson() {
            return new JSONSerializer()
                .exclude("*.class")
            .transform(new SOMapTransformer(), "items")
                .deepSerialize(this);
    }
}

Here is the custom SOMapTransformer:

import com.mycompany.mypackage.SomeBean;

import flexjson.JSONContext;
import flexjson.Path;
import flexjson.TypeContext;
import flexjson.transformer.AbstractTransformer;
import flexjson.transformer.TransformerWrapper;

    public class SOMapTransformer extends AbstractTransformer {

        public void transform(Object object) {
            JSONContext context = getContext();
            Path path = context.getPath();
            Map<String, List<SomeBean>> value = (Map<String, List<SomeBean>>) object;

            TypeContext typeContext = getContext().writeOpenObject();
            for (Object key : value.keySet()) {
                path.enqueue((String) key);

                //DPD 2013-11-04: This bloody line of code cost me 12 hours.  Comment it out!
//              if (context.isIncluded((String) key, value.get(key))) {

                    TransformerWrapper transformer = (TransformerWrapper)context.getTransformer(value.get(key));

                    if(!transformer.isInline()) {
                        if (!typeContext.isFirst()) getContext().writeComma();
                        typeContext.setFirst(false);
                        getContext().writeName(key.toString());
                    }

                    typeContext.setPropertyName(key.toString());

                    transformer.transform(value.get(key));

//              }

                path.pop();

            }
            getContext().writeCloseObject();
        }