Package com.swmansion.starknet.account

Account interface used to simplify preparing, signing Starknet transactions and automatic fee estimation.

import com.swmansion.starknet.account.Account;
import com.swmansion.starknet.account.StandardAccount;
import com.swmansion.starknet.data.types.*;
import com.swmansion.starknet.data.types.transactions.InvokeFunctionPayload;
import com.swmansion.starknet.provider.Provider;
import com.swmansion.starknet.provider.Request;
import com.swmansion.starknet.provider.rpc.JsonRpcProvider;

import java.util.List;

public class Main {
    public static void main(String[] args) {
        Provider provider = new JsonRpcProvider("https://example-node-url.com/rpc");
        Felt address = new Felt(0x1234);
        Felt privateKey = new Felt(0x1);
        Account account = new StandardAccount(address, privateKey, provider);

        // Execute a single call
        Felt maxFee = new Felt(10000000L);
        Felt contractAddress = new Felt(0x1111);
        Call call = new Call(contractAddress, "increase_balance", List.of(new Felt(100)));
        Request<InvokeFunctionResponse> request = account.execute(call, maxFee);
        InvokeFunctionResponse response = request.send();

        // Execute multiple calls
        Call call1 = new Call(contractAddress, "increase_balance", List.of(new Felt(100)));
        Call call2 = new Call(contractAddress, "increase_balance", List.of(new Felt(200)));
        account.execute(List.of(call1, call2), maxFee).send();

        // Use automatic maxFee estimation
        account.execute(call).send();
        // or 
        account.execute(List.of(call1, call2)).send();

        // Construct transaction step by step
        Call otherCall = new Call(contractAddress, "increase_balance", List.of(new Felt(100)));
        EstimateFeeResponse feeEstimate = account.estimateFee(otherCall).send();
        Felt nonce = account.getNonce().send();
        InvokeTransactionPayload signedTransaction = account.sign(otherCall, new ExecutionParams(nonce, maxFee));
        InvokeFunctionResponse signedInvokeResponse = provider.invokeFunction(signedTransaction).send();

        // Sign transaction for fee estimation only
        InvokeTransactionPayload transactionForFeeEstimation = account.sign(call, new ExecutionParams(nonce, Felt.ZERO), true);

        // Sign and verify TypedData signature
        TypedData typedData = TypedData.fromJsonString("...");
        List<Felt> typedDataSignature = account.signTypedData(typedData);
        Request<Boolean> isValidSignatureRequest = account.verifyTypedDataSignature(typedData, typedDataSignature);
        boolean isValidSignature = isValidSignatureRequest.send();
    }
}

or in Kotlin

fun main(args: Array<String>) {
    val provider: Provider = makeTestnetProvider()
    val address = Felt(0x1234)
    val privateKey = Felt(0x1)
    val account: Account = StandardAccount(address, privateKey, provider)

    // Execute a single call
    val maxFee = Felt(10000000L)
    val contractAddress = Felt(0x1111)
    val call = Call(contractAddress, "increase_balance", listOf(Felt(100)))
    val request = account.execute(call, maxFee)
    val response = request.send()

    // Execute multiple calls
    val call1 = Call(contractAddress, "increase_balance", listOf(Felt(100)))
    val call2 = Call(contractAddress, "increase_balance", listOf(Felt(200)))
    account.execute(listOf(call1, call2), maxFee).send()

    // Use automatic maxFee estimation
    account.execute(call).send()
    // or
    account.execute(listOf(call1, call2)).send()

    // Construct transaction step by step
    val otherCall = Call(contractAddress, "increase_balance", listOf(Felt(100)))
    val (gasConsumed, gasPrice, overallFee) = account.estimateFee(otherCall).send()
    val nonce = account.getNonce().send()
    val signedTransaction = account.sign(otherCall, ExecutionParams(nonce, maxFee))
    val signedInvokeResponse = provider.invokeFunction(signedTransaction).send()
    
    // Sign transaction for fee estimation only
    val transactionForFeeEstimation = account.sign(call, ExecutionParams(nonce, Felt.ZERO), true)

    // Sign and verify TypedData signature
    val typedData = TypedData.fromJsonString("...");
    val typedDataSignature = account.signTypedData(typedData)
    val isValidSignatureRequest = account.verifyTypedDataSignature(typedData, typedDataSignature)
    val isValidSignature = isValidSignatureRequest.send()
}