Is there a way to auto generate a flatten pojo from a pojo with object composition

Question

I need to store documents into Elasticsearch indexes and therefor I defined a mapping. From my java client I need to supply it with pojo's which looks like the Compony class. It has a lot of duplicated values. I could use object composition pattern to solve this, but Elasticsearch can't handle that kind of structure and therefor it expects a flatten structure.

class Company {
    private String postalstreetName;
    private String postalHouseNumer;
    private String postalHouseLetter;
    private String postalHouseNumberAddition;
    private String postalZipCode;
    private String postalCity;
    private String postalCountry;

    private String visitorstreetName;
    private String visitorHouseNumer;
    private String visitorHouseLetter;
    private String visitorHouseNumberAddition;
    private String visitorZipCode;
    private String visitorCity;
    private String visitorCountry;

    private String establishmentstreetName;
    private String establishmentHouseNumer;
    private String establishmentHouseLetter;
    private String establishmentHouseNumberAddition;
    private String establishmentZipCode;
    private String establishmentCity;
    private String establishmentCountry;
}

I actually want pojo's like below and somehow auto generate the pojo above with the same naming structure.

class Address {
    private String streetName;
    private String houseNumer;
    private String houseLetter;
    private String houseNumberAddition;
    private String zipCode;
    private String city;
    private String country;
}

class Company {
    private Address postalAddress;
    private Address visitorAddress;
    private Address establishmentAddress;
}

Does someone know if something like this is possible, to auto generate a flatten pojo from a pojo with object composition with a name prefix for all the fields?

Try http://www.jsonschema2pojo.org/ . It will generate Pojo classes if provided with any Json example. Atleast the effort for creating the class will be saved. — Shailesh Pratapwar, Jan 31 '19 at 11:37
Thank you, I tried it but it was not what I was searching for. It didn't create automatically nested objects — Hakan54, Feb 06 '19 at 12:45

Hakan54 · Accepted Answer · 2019-02-10T07:27:22.903

I got the solution for my problem. Elasticsearch is expecting a json object with the structure what I have in the first example. So what I did was adding the @JsonUnwrapped to the field with a prefix value, so my Company class looks like this:

class Company {
    @JsonUnwrapped(prefix = "postal")
    private Address postalAddress;
    @JsonUnwrapped(prefix = "visitor")
    private Address visitorAddress;
    @JsonUnwrapped(prefix = "Establishment")
    private Address establishmentAddress;
}

And the result will be:

{
  "postalStreetName":"",
  "postalHouseNumer":"",
  "postalHouseLetter":"",
  "postalHouseNumberAddition":"",
  "postalCity":"",
  "postalCountry":"",
  "visitorStreetName":"",
  "visitorHouseNumer":"",
  "visitorHouseLetter":"",
  "visitorHouseNumberAddition":"",
  "visitorCity":"",
  "visitorCountry":"",
  "establishmentStreetName":"",
  "establishmentHouseNumer":"",
  "establishmentHouseLetter":"",
  "establishmentHouseNumberAddition":"",
  "establishmentCity":"",
  "establishmentCountry":""
}

So I don't need to somehow magically create those pojo's because jackson can create the json files which I need.

Is there a way to auto generate a flatten pojo from a pojo with object composition

1 Answers1