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I am trying to parse a JSON string to a case class in Scala (So I can do the filtering data processing etc). After some research I am going with spray-json as there are several examples on the link. Unfortunately the link does not show how to parse a JSON with nested fields that have arrays.
I am testing my code on a Scala notebook with the code below and it works.
// Dependencies
io.spray spray-json_2.10 1.3.2
import spray.json._
import DefaultJsonProtocol._ // if you don't supply your own Protocol (see below)
// simple source
val source = """{
"EventId": "29ca61f3-b8b6-41e7-8236-802fa232e7cf",
"Timestamp": "2016-03-09T20:14:07.5535193Z",
"StartTime": "2016-03-09T02:51:04.397",
"EndTime": "2016-03-09T02:51:04.397",
"ActiveStates": "{\"No Motion\":1,\"Motion Detected\":1,\"Face Detected\":1}",
"Created": "2016-03-09T02:51:04.397",
"Modified": "2016-03-09T02:51:04.397"
}"""
// simple case class
case class claX( EventId: String,
Timestamp: String,
StartTime: String,
EndTime: String,
ActiveStates: String,
Created: String,
Modified: String)
object MyJsonProtocol extends DefaultJsonProtocol {
implicit val claXFormat = jsonFormat7(claX)
}
import MyJsonProtocol._
import spray.json._
val json = source.parseJson // parse string to json
val cx0 = json.convertTo[claX] // convert to class claX
My problem is when the JSON string has nested array in data that has a nested 'Product' class inside it. This is the sample JSON:
{
"EventId": "29ca61f3-b8b6-41e7-8236-802fa232e7cf",
"Timestamp": "2016-03-09T20:14:07.5535193Z",
"StartTime": "2016-03-09T02:51:04.397",
"EndTime": "2016-03-09T02:51:04.397",
"ActiveStates": "{\"No Motion\":1,\"Motion Detected\":1,\"Face Detected\":1}",
"Created": "2016-03-09T02:51:04.397",
"Modified": "2016-03-09T02:51:04.397",
"Data": {
"AgeRange": {
"Name": "30 - 35"
},
"Company": {
"Id": "f3ad1744-0ead-458a-9416-852c43ccde24"
},
"CompanyType": {
"Name": "Retailer"
},
"ConnectorType": {
"Name": "Camera Capturing"
},
"Content": {
"Ids": [
"0c0f0a9a-fece-4b3e-abb4-0f508d357220"
]
},
"Customer": {
"LoyaltyId": 0
},
"DeviceRegistries": [
{
"Id": "f19f5daa-e9b9-43d0-91a7-51da4fdd0e31",
"DeviceName": "Company 3 Cooler",
"DeviceType": "CCU"
}
],
"Emotion": {
"Name": "Happy"
},
"Gender": {
"Name": "Male"
},
"Products": [
{
"Name": "Molson Canadian",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935776",
"ProductPrice": {
"RetailPrice": 2.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 1.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Coors Original",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935775",
"ProductPrice": {
"RetailPrice": 1.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 0.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Coors Light",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935778",
"ProductPrice": {
"RetailPrice": 6.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 5.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Blue Moon",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935777",
"ProductPrice": {
"RetailPrice": 4.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 3.8,
"PromotionPriceSymbol": "?"
}
}
],
"Race": {
"Name": "Latin"
},
"Region": {
"Name": "Region 01"
},
"SensorRegistry": {
"Name": "Company 3 Camera 01"
},
"SensorType": {
"Name": "Proximity"
},
"SfuRegistries": {
"Ids": [
"7effea8c-56dd-4905-bbc3-2158d14cd7cc",
"24a7253d-174a-44f0-8145-483cc0f45adb",
"bc970c8e-7e41-4889-859b-55c6a3f8ba5d",
"46e599f5-8082-499f-b5d0-9d611409a652"
]
},
"Shelves": {
"Ids": [
"ea442504-7d64-4c01-bdde-1eb46e53b81c",
"d6fe9c78-e21b-4a57-b620-99a7d94d46f9"
]
},
"State": {
"Name": "Face Detected"
},
"StockLevel": {
"OnHand": 0
},
"Store": {
"Id": "268c852d-86b8-4b7c-b865-2f29a3e2307e"
},
"Unit": {
"Id": "52c58781-b2bf-46ea-81ad-b9d9fbacb471"
},
"UnitType": {
"Name": "5-Shelf Cooler"
}
},
"id": "54bfd971-0fec-4e0e-87cc-851a697705e9"
}
I've made two more case classes to manage the 'Product' and the 'Prices'
case class ProductPrice(RetailPrice: Double,
RetailPriceSymbol: Double,
PromotionPrice: Double,
PromotionPriceSymbol: Double)
case class Product(Name: String,
ProductCategory: String,
InventoryTrackingNumberType: String,
InventoryTrackingNumber: String,
ProductPrice: ProductPrice)
What I don't know is how do you combine this so that the Data node in the JSON is parsed properly into a claXBig (where everything from the JSON string is correctly parsed. This is where I am tripping up:
case class claX2( EventId: String,
Timestamp: String,
StartTime: String,
EndTime: String,
ActiveStates: String,
Created: String,
Modified: String,
Data: Map[String, Any]) // <- how do I parse this and the nested products
object MyJsonProtocol2 extends DefaultJsonProtocol {
implicit val claXFormat2 = jsonFormat8(claX2)
}
I'm also trying to load a larger JSON (collection of these 'events') using code outlined here
So I added a new case class below to handle the array of 'event's or claX2
case class claX2Collection(clax2s: Array[claX2])
extends IndexedSeq[claX2] {
def apply(index: Int) = clax2s(index) //<- not sure what this mean
def length = clax2s.length // or whether index is doing anything
}
I assume claX2Collection is correct as its compiling. But the code below is definitely wrong, but is needed to load the event collection from the JSON array
implicit object claX2JsonFormat extends RootJsonFormat[claX2]{
def write(f: claX2) = {
val buf = scala.collection.mutable.ArrayBuffer(
"events" -> JsString("claX2"), // <- error
"Timestamp" -> JsObject(f.Timestamp), // error
"StartTime" -> JsObject(f.StartTime), // error
"EndTime" -> JsObject(f.EndTime), // error
"ActiveStates" -> JsObject(f.ActiveStates), // error
"Created" -> JsObject(f.Created), // errors
"Modified" -> JsObject(f.Modified), // errors
"Data" -> JsObject(f.Data) // errors
)
}
def read(value:JsValue) = {
val jso = value.asJsObject
// not sure what to do here but
// assuming I have to pick out
val EventId = jso.fields.get("EventId")
Timestamp = jso.fields.get("Timestamp")
StartTime = jso.fields.get("StartTime")
EndTime = jso.fields.get("EndTime")
ActiveStates = jso.fields.get("ActiveStates")
Created = jso.fields.get("Created")
Modified = jso.fields.get("Modified")
Data = jso.fields.get("Data")
claX2(EventId,Timestamp,StartTime,EndTime,ActiveStates,Created,
Modified,Data)
}
}
When that is fixed it should be able to read this JSON:
{
"type": "EventCollection",
"events": [
{
"EventId": "29ca61f3-b8b6-41e7-8236-802fa232e7cf",
"Timestamp": "2016-03-09T20:14:07.5535193Z",
"StartTime": "2016-03-09T02:51:04.397",
"EndTime": "2016-03-09T02:51:04.397",
"ActiveStates": "{\"No Motion\":1,\"Motion Detected\":1,\"Face Detected\":1}",
"Created": "2016-03-09T02:51:04.397",
"Modified": "2016-03-09T02:51:04.397",
"Data": {
"AgeRange": {
"Name": "30 - 35"
},
"Company": {
"Id": "f3ad1744-0ead-458a-9416-852c43ccde24"
},
"CompanyType": {
"Name": "Retailer"
},
"ConnectorType": {
"Name": "Camera Capturing"
},
"Content": {
"Ids": [
"0c0f0a9a-fece-4b3e-abb4-0f508d357220"
]
},
"Customer": {
"LoyaltyId": 0
},
"DeviceRegistries": [
{
"Id": "f19f5daa-e9b9-43d0-91a7-51da4fdd0e31",
"DeviceName": "Company 3 Cooler",
"DeviceType": "CCU"
}
],
"Emotion": {
"Name": "Happy"
},
"Gender": {
"Name": "Male"
},
"Products": [
{
"Name": "Molson Canadian",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935776",
"ProductPrice": {
"RetailPrice": 2.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 1.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Coors Original",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935775",
"ProductPrice": {
"RetailPrice": 1.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 0.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Coors Light",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935778",
"ProductPrice": {
"RetailPrice": 6.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 5.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Blue Moon",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935777",
"ProductPrice": {
"RetailPrice": 4.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 3.8,
"PromotionPriceSymbol": "?"
}
}
],
"Race": {
"Name": "Latin"
},
"Region": {
"Name": "Region 01"
},
"SensorRegistry": {
"Name": "Company 3 Camera 01"
},
"SensorType": {
"Name": "Proximity"
},
"SfuRegistries": {
"Ids": [
"7effea8c-56dd-4905-bbc3-2158d14cd7cc",
"24a7253d-174a-44f0-8145-483cc0f45adb",
"bc970c8e-7e41-4889-859b-55c6a3f8ba5d",
"46e599f5-8082-499f-b5d0-9d611409a652"
]
},
"Shelves": {
"Ids": [
"ea442504-7d64-4c01-bdde-1eb46e53b81c",
"d6fe9c78-e21b-4a57-b620-99a7d94d46f9"
]
},
"State": {
"Name": "Face Detected"
},
"StockLevel": {
"OnHand": 0
},
"Store": {
"Id": "268c852d-86b8-4b7c-b865-2f29a3e2307e"
},
"Unit": {
"Id": "52c58781-b2bf-46ea-81ad-b9d9fbacb471"
},
"UnitType": {
"Name": "5-Shelf Cooler"
}
},
"id": "54bfd971-0fec-4e0e-87cc-851a697705e9"
},
{
"EventId": "29ca61f3-b8b6-41e7-8236-802fa232e7cf",
"Timestamp": "2016-03-09T20:14:07.5535193Z",
"StartTime": "2016-03-09T02:51:04.397",
"EndTime": "2016-03-09T02:51:04.397",
"ActiveStates": "{\"No Motion\":1,\"Motion Detected\":1,\"Face Detected\":1}",
"Created": "2016-03-09T02:51:04.397",
"Modified": "2016-03-09T02:51:04.397",
"Data": {
"AgeRange": {
"Name": "30 - 35"
},
"Company": {
"Id": "f3ad1744-0ead-458a-9416-852c43ccde24"
},
"CompanyType": {
"Name": "Retailer"
},
"ConnectorType": {
"Name": "Camera Capturing"
},
"Content": {
"Ids": [
"0c0f0a9a-fece-4b3e-abb4-0f508d357220"
]
},
"Customer": {
"LoyaltyId": 0
},
"DeviceRegistries": [
{
"Id": "f19f5daa-e9b9-43d0-91a7-51da4fdd0e31",
"DeviceName": "Company 3 Cooler",
"DeviceType": "CCU"
}
],
"Emotion": {
"Name": "Happy"
},
"Gender": {
"Name": "Male"
},
"Products": [
{
"Name": "Molson Canadian",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935776",
"ProductPrice": {
"RetailPrice": 2.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 1.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Coors Original",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935775",
"ProductPrice": {
"RetailPrice": 1.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 0.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Coors Light",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935778",
"ProductPrice": {
"RetailPrice": 6.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 5.8,
"PromotionPriceSymbol": "?"
}
},
{
"Name": "Blue Moon",
"ProductCategory": "Beverage",
"InventoryTrackingNumberType": "SKU",
"InventoryTrackingNumber": "438654935777",
"ProductPrice": {
"RetailPrice": 4.1,
"RetailPriceSymbol": "?",
"PromotionPrice": 3.8,
"PromotionPriceSymbol": "?"
}
}
],
"Race": {
"Name": "Latin"
},
"Region": {
"Name": "Region 01"
},
"SensorRegistry": {
"Name": "Company 3 Camera 01"
},
"SensorType": {
"Name": "Proximity"
},
"SfuRegistries": {
"Ids": [
"7effea8c-56dd-4905-bbc3-2158d14cd7cc",
"24a7253d-174a-44f0-8145-483cc0f45adb",
"bc970c8e-7e41-4889-859b-55c6a3f8ba5d",
"46e599f5-8082-499f-b5d0-9d611409a652"
]
},
"Shelves": {
"Ids": [
"ea442504-7d64-4c01-bdde-1eb46e53b81c",
"d6fe9c78-e21b-4a57-b620-99a7d94d46f9"
]
},
"State": {
"Name": "Face Detected"
},
"StockLevel": {
"OnHand": 0
},
"Store": {
"Id": "268c852d-86b8-4b7c-b865-2f29a3e2307e"
},
"Unit": {
"Id": "52c58781-b2bf-46ea-81ad-b9d9fbacb471"
},
"UnitType": {
"Name": "5-Shelf Cooler"
}
},
"id": "54bfd971-0fec-4e0e-87cc-851a697705e9"
}
]
}
205
This is the complete solution The git repo for the solution and data files is here
import spray.json._
import DefaultJsonProtocol._
object parseJson {
def main(args: Array[String]){
// case classes for all the nested information in the
case class Ids(Ids: Seq[String])
case class Id(Id: String)
case class Name(Name: String)
case class OnHand(OnHand: Int)
case class LoyaltyId(LoyaltyId: Int)
case class ProductPrice(RetailPrice: Double,
RetailPriceSymbol: String,
PromotionPrice: Double,
PromotionPriceSymbol: String)
case class Product(Name: String,
ProductCategory: String,
InventoryTrackingNumberType: String,
InventoryTrackingNumber: String,
ProductPrice: ProductPrice)
case class Data(Content: Ids,
SfuRegistries: Ids,
AgeRange: Name,
Company: Id,
SensorType: Name,
StockLevel: OnHand,
Region: Name,
UnitType: Name,
Emotion: Name,
Shelves: Ids,
Customer: LoyaltyId,
DeviceRegistries: Seq[Map[String, String]],
ConnectorType: Name,
CompanyType: Name,
State: Name,
Gender: Name,
SensorRegistry: Name,
Race: Name,
Store: Id,
Products: Seq[Product])
case class Element(EventId: String,
Timestamp: String,
StartTime: String,
EndTime: String,
ActiveStates: String,
Created: String,
Modified: String,
Data: Data)
// This is the code that is blowing up
case class RootCollection(items: Array[Element]) extends IndexedSeq[Element]{
def apply(index: Int) = items(index)
def length = items.length
}
object MyJsonProtocol extends DefaultJsonProtocol {
implicit val nameFormat = jsonFormat1(Name)
implicit val productPriceFormat = jsonFormat4(ProductPrice)
implicit val productFormat = jsonFormat5(Product)
implicit val loyaltyIdFormat = jsonFormat1(LoyaltyId)
implicit val onHandFormat = jsonFormat1(OnHand)
implicit val idFormat = jsonFormat1(Id)
implicit val idsFormat = jsonFormat1(Ids)
implicit val dateFormat = jsonFormat20(Data)
implicit val ElementFormat = jsonFormat8(Element)
implicit object RootCollectionFormat extends RootJsonFormat[RootCollection] {
def read(value: JsValue) = RootCollection(value.convertTo[Array[Element]])
def write(f: RootCollection) = JsArray(f.toJson)
}
}
import MyJsonProtocol._
println("Running Parse JSON")
val input = scala.io.Source.fromFile("sample2.json")("UTF-8").mkString.parseJson
//println("JSON string read:")
//println(input)
val jsonCollection = input.convertTo[RootCollection]
// print some items
jsonCollection.map(y => y.Data.Products.map(x => println(x)))
println(jsonCollection.length)
}
}
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