java - 如何调用返回 tuple[] 的函数

Question

我对使用 Java 与智能合约进行交互还比较陌生，在尝试检索智能合约函数返回的元组 [] 时遇到了问题。这是我要调用的函数的 ABI 定义:

{
  "inputs":[{"internalType":"address","name":"account","type":"address"}],
  "name":"claimableRewards",
  "outputs":
    [{"components":
      [
        {"internalType":"address","name":"token","type":"address"},
        {"internalType":"uint256","name":"amount","type":"uint256"}
      ],
      "internalType":"struct MultiFeeDistribution.RewardData[]",
      "name":"rewards",
      "type":"tuple[]"
    }],
  "stateMutability":"view",
  "type":"function"
}

这是智能合约代码的链接: https://polygonscan.com/address/0x920f22e1e5da04504b765f8110ab96a20e6408bd#code

下面是我为调用该函数而编写的 Java 代码(我删除了错误检查以使代码更易于阅读):

List<Type> claimableRewardsParams = Arrays.<Type>asList(new Address(credentials.getAddress()));
List<TypeReference<?>> claimableRewardsReturnTypes = Arrays.<TypeReference<?>>asList(new TypeReference<DynamicArray<DynamicStruct>>() {});

final Function claimableRewardsFunction = new Function(
        "claimableRewards",
        claimableRewardsParams,
        claimableRewardsReturnTypes);

String claimableRewardsEncodedFunction = FunctionEncoder
        .encode(claimableRewardsFunction);          

EthCall claimableRewardsResponse = web3.ethCall(
        Transaction.createEthCallTransaction(walletAddress, adamantRewardsContractAddress, claimableRewardsEncodedFunction),
        DefaultBlockParameterName.LATEST)
        .sendAsync().get();

List<Type> claimableRewardsSomeTypes = FunctionReturnDecoder.decode(
        claimableRewardsResponse.getValue(), claimableRewardsFunction.getOutputParameters());

当我运行程序时出现以下异常:

Exception in thread "main" java.lang.RuntimeException: TypeReferencedstruct must contain a constructor with types that extend Type

我已经为 claimableRewardsReturnTypes 尝试了其他几个定义，但我无法让它工作。有人可以帮帮我吗？

Answer 1

您需要定义一个扩展 DynamicStruct 的类

public class RewardData extends DynamicStruct {
    public RewardData(Address token, Uint256 amount) {
        super(new Type[]{token, amount});
    }
}

然后用RewardData替换DynamicStruct

List<TypeReference<?>> claimableRewardsReturnTypes = Arrays.<TypeReference<?>>asList(new TypeReference<DynamicArray<RewardData>>() {});