Jackson readValue mapping to overloaded java class problem - json

Question

I have some JSON where one of the keys has one of three values: an int, a string, or a json object. Using the snippet below I can map this field when it is an int or a string but fail when it's a json object. Where am I going wrong? What should I be doing?
The JSON value key looks like:
"value": 51,
or
"value": 51,
or (and this is where I am having trouble)
"value": {"lat": 53.990614999999998, "lng": -1.5391117000000301, "addr": "Harrogate, North Yorkshire, UK"}
public class Test {
public Test() {
}
public static class Value {
public int slidervalue;
public String voicevalue;
public GeoValue geovalue; // problem
public Value(int value) {
this.slidervalue = value
}
public Value(String value) {
this.voicevalue = value;
}
public Value(JSONObject value) {
JSONObject foo = value; // this is never reached
this.geovalue = value; // and how would this work so as map value to a GeoValue?
}
private static class GeoValue {
private double _lat;
private double _lng;
private String _addr;
public float getLat() {
return (float)_lat;
}
public void setLat(float lat) {
_lat = (double)lat;
}
public float getLng() { return (float)_lng;}
public void setLng(float lng) { _lng = (double)lng; }
public String getAddr() { return _addr;}
public void setAddr(String addr) { _addr = addr; }
}
} // end of Value class
public Value getValue() { return _value;}
public void setValue(Value value) {
_value = value;
}
} //end of Test class
and this is being used like this:
ObjectMapper mapper = new ObjectMapper();
instance = mInstances.getJSONObject(i).toString();
Test testinstance = mapper.readValue(instance, Test.class);
public class Test {
public Test() {
}
public static class Value {
public int slidervalue;
public String voicevalue;
public GeoValue geovalue; // problem
public Value(int value) {
this.slidervalue = value
}
public Value(String value) {
this.voicevalue = value;
}
public Value(JSONObject value) {
JSONObject foo = value; // this is never reached
this.geovalue = value; // and how would this work so as map value to a GeoValue?
}
private static class GeoValue {
private double _lat;
private double _lng;
private String _addr;
public float getLat() {
return (float)_lat;
}
public void setLat(float lat) {
_lat = (double)lat;
}
public float getLng() { return (float)_lng;}
public void setLng(float lng) { _lng = (double)lng; }
public String getAddr() { return _addr;}
public void setAddr(String addr) { _addr = addr; }
}
} // end of Value class
public Value getValue() { return _value;}
public void setValue(Value value) {
_value = value;
}
} //end of Test class
and this is being used like this:
ObjectMapper mapper = new ObjectMapper();
instance = mInstances.getJSONObject(i).toString();
Test testinstance = mapper.readValue(instance, Test.class);
This fails with a JSONMappingException: No suitable contructor found for type ... 'value'
Thanks. Alex

Answer 1

What might work is that you mark the constructor that takes JSONObject with #JsonCreator, but do NOT add #JsonProperty for the single parameter. In that case, incoming JSON is bound to type of that parameter (in this case JSONObject, but you could use Map as well), and passed to constructor.
Overloading still works because of special handling for single-string/int/long-argument constructor.
I am not sure if that is the cleanest solution; it might be cleanest to just implement custom deserializer. But it should work.

Answer 2

If your code is what you want, your json should be like this:
{"value":{"slidervalue":1,"voicevalue":"aa","geovalue":{"lat":53.990615,"lng":-1.53911170000003,"addr":"Harrogate, North Yorkshire, UK"}}}