Display two domain object values as one JSON output - json

Question

I am working on grails and I have a use case with two domain classes class A and class B which are independent classes.I want the class A and class B values in one JSON view.
class A
String name,
String age
class B
String report
In Bootstrap.groovy file i have written the below format to display the values in JSON view.
JSON.registerObjectMarshaller(A) {it->
def result = [:]
result['name'] = it.name
result['age'] = it.age
result['report'] = it.report //It throws an error no such property: report for class A.How to write it in a proper JSON format to retrieve the report value?
return result
}

Answer 1

From the documentation
Groovy comes with integrated support for converting between Groovy
objects and JSON. The classes dedicated to JSON serialisation and
parsing are found in the groovy.json package.
For example you could use groovy.json.JsonBuilder
In your example you could try this
Having classes A and B
class A {
String name
String age
}
class B {
String report
}
Import JsonBuilder in Bootstrap.groovy file
import groovy.json.JsonBuilder
An then you can try
A a = new A(name: 'ana', age: '15')
B b = new B(report: 'lorem ipsum...')
JsonBuilder jsonBuilder = new JsonBuilder()
jsonBuilder.result {
name a.name
age a.age
report b.report
}
println jsonBuilder.toString()
Output
{"result":{"name":"ana","age":"15","report":"lorem ipsum..."}}

Answer 2

If you want a more reusable code, then you can create a new class with public properties you want to show up in the json result.
class MyJSONResult(){
String name
String age
String report
// add more properties as needed
// constructor
MyJSONResult(A a, B b){
name = a.name
age = a.name
report = b.report
}
}
//when you need json result,
import grails.converters.JSON
def json = new MyJSONResult(a, b)
render json as JSON
The good thing about creating a new class and an object is that you can reuse it. For example if you needed to show the same result in the gsp page, you can pass the object to a view and access its properties.
def json = new MyJSONResult(a, b)
render view:'myview', model:[myVar: json]
// in gsp views
${myVar.name}
This way any business logic you used in building the json payload can be used for your api or anywhere else you may need to use them