johnson

Jackson based deserialisation with variable injection/replacement

Introduction

This library allow to put some variables in json, after the deserialization performed by jackson, it will replace the variable by the value found in the object.

For example :

{
  "title" : "Test",
  "author": "Johnson",
  "subtitle" : "${title} - Subtest"
}

In java side :

foo.getSubtitle(); // Will returns "Test - Subtest"

For example 2 :

{
  "url": {
    "prod": "http://some.prod.url/",
    "dev": "http://some.dev.url/"
  },
  "sites": {
    "images": "${url.prod}images",
    "thumbnails": "${url.dev}thumbs"
  }
}

In Java side :

foo2.getSites().getImages(); // Will returns "http://some.prod.url/images"
foo2.getSites().getThumbnails(); // Will returns "http://some.dev.url/thumbs"

Usage

To perform the variable injection, let's suppose that you have the json string in the variable "json"

String json = "{...}"
// Instanciate the mapper
Mapper mapper = new Mapper();
// The Book class is the object representation of the json
Book book = mapper.readValue(json, Book.class);

Or if you don't need to perform the serialization stuff

// Instanciate the mapper
Mapper mapper = new Mapper();
// Just perform the variable substitution in an object
Book injectedBook = mapper.injectValue(book);

That it's !

Warning

This mapper is suitable for small, medium objects. Do not use this for huge, deep object, it perform java reflection and performance is really low.