ElasticSearch Symfony : Tree Category

Hello,

I have entity book, in this entity i have association with category. In my entity category i can get parent with method. In my mapping (config.yml) i have this :

book:
mappings:
name: ~
bookCategory: { type: 'object', properties: { id : {type: 'integer'}, name: {type: 'string', index: 'not_analyzed'}, parent: {type: 'object', properties: {name: {type: 'string', index: 'not_analyzed'}, parent: {type: 'object', properties: {name: {type: 'string', index: 'not_analyzed'}}}}} } }
persistence:
driver: 'orm'
model: 'AppBundle\Entity\Book\Book'
provider:
batch_size: 5000
listener: ~
finder: ~

I get my categories but separately.

category : [key,count]
subCategory: [key, count]
subsubCategory: [key, count]

i need this :

category : [key, count, subCategory [ key, count, subsubCategory [ key, count]]]

Thanks,
Sorry for my bad english