Question

I’m using playframework, is there any way to convert a java object into Play recognizable pojo parameter list?
For example I have two class

public class A{
    B b;
    String room;
}
public class B{
    String name;
}

When I get a A instance a, I can change it into two parameters

a.room=myroom&a.b.name=myname

Do I have to travel through a json converted from that instance?

Thanks a lot.

Answer 1

I wrote a Util to convert Object to playframework friendly parameter list with jackson.databind

public static List<MutablePair> getPojoParam(Object base, Object obj, boolean firstLevel) {
    List<MutablePair> ret = new ArrayList<MutablePair>();
    String realBase = (firstLevel) ? (String) base : ("." + base);

    if (obj instanceof Collection) {
        int count = 0;
        for (Object o : (Collection) obj) {
            List<MutablePair> subPair = getPojoParam(base, o, false);
            for (MutablePair p : subPair) {
                p.left = realBase + "[" + (count++) + "]" + p.left;
                ret.add(p);
            }
        }
    } else if (obj instanceof Map) {
        Map<Object, Object> map = (Map<Object, Object>) obj;
        for (Object k : map.keySet()) {
            List<MutablePair> subPair = getPojoParam(k, map.get(k), false);
            for (MutablePair p : subPair) {
                p.left = realBase + p.left;
                ret.add(p);
            }
        }
    } else {
        ret.add(new MutablePair(realBase, obj));
    }
    return ret;
}

Usage:

ATest a = new ATest();
ObjectMapper mapper = new ObjectMapper(); 
Map<String, Object> data = mapper.readValue(new Gson().toJson(a), Map.class);
List<MutablePair> ret = ObjectToPOJO.getPojoParam("source", data, true);
for (MutablePair key : ret) {
    System.out.println(key.left + "=" + key.right);
}

I hope it’s right.

Add dependencies to use MutablePair and jackson.databind

require:
    - com.fasterxml.jackson.core -> jackson-databind 2.1.0
    - org.apache.commons -> commons-lang3 3.1