Additional pagination support for NftRepository

[hendrikebbers]

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👾 Description of the issue

The interface NftRepository provides query functionallity for NFTs. The functionality is based on the REST endpoints of the mirror node. The following messages uses the Page interface to support pagination for the query:

Page<Nft> findByType(@NonNull TokenId tokenId)

The Page interface provides pagination access to the query result. That is needed since a REST call to the endpoint of mirror node does not return all results but a list and possible link to a next query that will contain additional results ( and a link to a next query). Example of a JSON based result:

Query:

curl -X 'GET' \
  'https://testnet.mirrornode.hedera.com/api/v1/contracts?limit=2&order=asc' \
  -H 'accept: application/json'

Result:

{
  "contracts": [
    {
      "contract_id": "0.0.1253",
      // way more attributes that I removed for a better sample
    },
    {
      "contract_id": "0.0.1257",
      // way more attributes that I removed for a better sample
    }
  ],
  "links": {
    "next": "/api/v1/contracts?limit=2&order=asc&contract.id=gt:0.0.1257"
  }
}

The follwing 2 methods currently do not support pagination and will only return the results of the first page:

List<Nft> findByOwner(@NonNull AccountId ownerId)

List<Nft> findByOwnerAndType(@NonNull AccountId ownerId, @NonNull TokenId tokenId)

The two methods need to be refactored:

Page<Nft> findByOwner(@NonNull AccountId ownerId)

Page<Nft> findByOwnerAndType(@NonNull AccountId ownerId, @NonNull TokenId tokenId)

Suggestion for solving the issue

Refactor the NftRepository interface as described. By doing so you will see that the MirrorNodeClient interface is used internally in the implementation. That interface and the implementation of that interface (that is part of the spring module) need to be refactored, too. The MirrorNodeClientImpl implementation already contains a pagination-based implementation for the following method:

public Page<Nft> queryNftsByTokenId(@NonNull TokenId tokenId)

That method can be used as a sample how a concrete implementation should look like.

Additional information

General information about pagination can be found here and here.

Information about the rest api of the mirror node can be found here. The API can be accessed by Swagger UI. The Swagger UI frontend for testnet can be found here.

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🤔 Additional informantion

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[henrique021]

hi, i would like to work on this issue.

[hendrikebbers]

sure :)

[Ndacyayisenga-droid]

@hendrikebbers was this issue fully fixed here #27 so we can close it?

[hendrikebbers]

@Ndacyayisenga-droid you are right.