Adding a dynamic json property as java pojo for jackson

Question

I need to create a Json payload like this from Java pojo :

{ \"update\" : {
    \"labels\" : [{\"add\" : \"A label\"} ]
    }
 }

so I crea

Answer 1

Your specification isn't clear, you would have many of the same action (add, remove, etc) or just one at most?

First Option
In case you have at most single instance of the same action, you can replace the array with regular object:

{ "update" : {
    "labels" : {
       "add" : "A label",
       "remove" : "B label"
      }
    }
 }

and then change your labels to a Map instead of List

Second Option
In case you have many instances of the same action, you can change the design of label to contain two fields, value and action

{ "update" : {
    "labels" : [{"action": "add", "value" : "A label"} ]
    }
 }

And update Label accordingly:

  public static class Label{
    public String action;
    public String value 
    public Label(String action, String value){
       this.action = action;
       this.value = value; 
    }
  }

You can also change action to enum which define all your possible actions

Third Option
If you really need to stick to your json design, you don't have a lot of options to define static typing class for a dynamic json. maybe it's possible to hack this somehow using jackons's polymorphism. But you can always just use the json objects and leave the labels as List