How can I create a json with the opportunity products with a specific format?

Question

I have a specific format of the Json that I save with opportunity and account values, as in the example below, but in the LINEAS section would depend on the number of products that have the opportunity, how could I do that?

req.setBody(
            ' "Negociación":'+'{'+
                '"PorcentajeAumentoAnual": "'             + SelOportunity.PAA__c                                +'",'   +  
                '"PorcentajeAumentoAnual": "'             + SelOportunity.Porcentaje_Aumento_Anual_Piso__c      +'",'   +            
                '"TipoNegociacion": "'                    + SelOportunity.Tipo_de_Renta__c                      +'",'   +
            ' "Lineas":'+'['+
            '{'+
                /*'"RecordIdLinea": "'                    + SelProduct.Id                      +'",'   +
                '"Categoria": "'                          + SelProduct.Articulo__c             +'",'   +
                '"Cantidad": "'                           + SelProduct.Quantity                +'",'   +
                '"CAM": "'                                + SelProduct.Total_CAM__c            +'",'   +            
                '"PrecioUnitarioLocal": "'                + SelProduct.Prorrateo__c            +'"'    +
                '"PrecioTotalLinea": "'                   + SelProduct.Prorrateo__c            +'",'   +       
                '"IDLocal": "'                            + SelProduct.ProductCode             +'",'   +*/   
            '}' +
            '],
)

With the following query I obtain the products related to the opportunity with the data that it would occupy, but that data would be assigned to the values ​​of the LINEAS segment of the Json

Opportunity op = [SELECT id, (SELECT Id,Articulo__c,Quantity,Total_CAM__c,Prorrateo__c,ProductCode FROM opportunitylineitems)FROM opportunity WHERE Id =: OpportunityId];

How could you make the line part dynamic depending on the number of products of the opportunity?

Saludos!

Answer 1

You could use JSONGenerator class and as part of the methods in this class, use writeStartArray and writeEndArray to build the array of opp line items related to an opportunity.

Here's a sample code to get you started:

Opportunity op = [SELECT id, Name,(SELECT Id,Name,quantity FROM opportunitylineitems)
FROM opportunity WHERE Id=: OpportunityId]; //replace relevant fields here

JSONGenerator gen = JSON.createGenerator(true);
gen.writeStartObject();
gen.writeFieldName('Negociación');
gen.writeStartObject();
gen.writeStringField('PorcentajeAumentoAnual', op.Name);//replace field
gen.writeStringField('TipoNegociacion', op.Name); //replace field 
//complete other fields from opportunity 

gen.writeFieldName('Lineas');
    gen.writeStartArray();
        for (integer i = 0; i < op.opportunitylineitems.size(); i++){
            gen.writeStartObject();
            gen.writeStringField('Categoria', op.opportunitylineitems[i].Name); //replace field 
            gen.writeStringField('Cantidad', op.opportunitylineitems[i].Name); //replace field
            //complete other fields from opportunitylineitems 
            gen.writeEndObject();
        }
    gen.writeEndArray();
gen.writeEndObject();

system.debug(gen.getAsString() );

Sample JSON result:

{
    "Negociación": {
        "PorcentajeAumentoAnual": "value here",
        "TipoNegociacion": "value here",
        "Lineas": [
            {
                "Categoria": "value here",
                "Cantidad": "value here"
            },
            {
                "Categoria": "value here",
                "Cantidad": "value here"
            },
            {
                "Categoria": "value here",
                "Cantidad": "value here"
            }
        ]
    }
}

Answer 2

I would suggest you to user a wrapper inner class for both, Negociacion and Lineas. Then for every record in the query I would create one new Linea() and, at the end, I will JSON.serialize() the main wrapper object. It should be "easy", does it make sense for you?