Smart Contract Execution

TxTypeSmartContractExecution executes a smart contract with the given data. TxTypeSmartContractExecution is accepted only if "to" is a smart contract account.

Import necessary classes from the Web3j and kaia libraries(web3j-ext).

Connect to the kaia blockchain using Web3j and specify the URL

Create KlayCredentials using the private key

Define gas price and gas limit for the transaction

Get the sender's address and nonce

Define the contract data that will be sent to blockchain

Get the chain ID from the Kaia network

Initialize variables for transaction parameters

Create a raw transaction

Sign the raw transaction

Send the transaction to kaia network.

Get the transaction receipt and using the transaction hash

Shutdown the Web3j instance

Decode the raw transaction to get the transaction type

SmartContractExecutionExample.java

package org.web3j.example.transactions;

import java.io.IOException;

import java.math.BigInteger;

import org.web3j.crypto.KlayCredentials;

import org.web3j.crypto.KlayRawTransaction;

import org.web3j.crypto.KlayTransactionEncoder;

import org.web3j.crypto.transaction.type.TxType;

import org.web3j.crypto.transaction.type.TxTypeSmartContractExecution;

import org.web3j.crypto.transaction.type.TxType.Type;

import org.web3j.protocol.core.DefaultBlockParameterName;

import org.web3j.protocol.core.methods.response.EthChainId;

import org.web3j.protocol.core.methods.response.EthSendTransaction;

import org.web3j.protocol.http.HttpService;

import org.web3j.protocol.kaia.Web3j;

import org.web3j.utils.Numeric;

import org.web3j.protocol.kaia.core.method.response.TransactionReceipt;

import org.web3j.tx.response.PollingTransactionReceiptProcessor;

import org.web3j.tx.response.TransactionReceiptProcessor;

import org.web3j.example.keySample;

/**

*

*/

public class SmartContractExecutionExample implements keySample {

/**

*

*/

public static void run() throws Exception {

Web3j web3j = Web3j.build(new HttpService(keySample.BAOBAB_URL));

KlayCredentials credentials = KlayCredentials.create(keySample.LEGACY_KEY_privkey);

BigInteger GAS_PRICE = BigInteger.valueOf(50000000000L);

BigInteger GAS_LIMIT = BigInteger.valueOf(6721950);

String from = credentials.getAddress();

BigInteger nonce = web3j.ethGetTransactionCount(from, DefaultBlockParameterName.LATEST).send()

.getTransactionCount();

String data = "0xcfae3217";

EthChainId EthchainId = web3j.ethChainId().send();

long chainId = EthchainId.getChainId().longValue();

String to = "0xc58294ecde8fdb288fd845e7a43a56564b597bdb";

byte[] payload = Numeric.hexStringToByteArray(data);

BigInteger value = BigInteger.ZERO;

TxType.Type type = Type.SMART_CONTRACT_EXECUTION;

KlayRawTransaction raw = KlayRawTransaction.createTransaction(

type,

nonce,

GAS_PRICE,

GAS_LIMIT,

to,

value,

from,

payload);

byte[] signedMessage = KlayTransactionEncoder.signMessage(raw, chainId, credentials);

String hexValue = Numeric.toHexString(signedMessage);

EthSendTransaction transactionResponse = web3j.ethSendRawTransaction(hexValue).send();

System.out.println("TxHash : \n " + transactionResponse.getResult());

String txHash = transactionResponse.getResult();

int DEFAULT_POLLING_ATTEMPTS_PER_TX_HASH = 40;

int DEFAULT_BLOCK_TIME = 1 * 1000;

long DEFAULT_POLLING_FREQUENCY = DEFAULT_BLOCK_TIME;

TransactionReceiptProcessor transactionReceiptProcessor = new PollingTransactionReceiptProcessor(web3j,

DEFAULT_POLLING_FREQUENCY, DEFAULT_POLLING_ATTEMPTS_PER_TX_HASH);

org.web3j.protocol.core.methods.response.TransactionReceipt ethReceipt = transactionReceiptProcessor

.waitForTransactionReceipt(txHash);

System.out.println("Receipt from eth_getTransactionReceipt : \n" + ethReceipt);

TransactionReceipt receipt = web3j.klayGetTransactionReceipt(txHash).send().getResult();

System.out.println("Receipt from klay_getTransactionReceipt : \n" + receipt);

web3j.shutdown();

TxTypeSmartContractExecution rawTransaction = TxTypeSmartContractExecution

.decodeFromRawTransaction(signedMessage);

System.out.println("TxType : " + rawTransaction.getKlayType());

}

}

output

❯ java SmartContractExecutionExample.java

TxHash :

0xb04136d9704df78a49e54e9f9ae61df4d39dc5c249aba84bc1a4e4cdc64b00eb

receipt :

class TransactionReceipt {

blockHash: 0x8aee92edc199854646f999e094047da3a127d15473716c8dd40f42985a93be52

blockNumber: 0x8dea9cd

codeFormat: null

contractAddress: null

feePayer: null

feePayerSignatures: []

feeRatio: null

from: 0xa2a8854b1802d8cd5de631e690817c253d6a9153

gas: 0x66919e

effectiveGasPrice: 0x5d21dba00

gasPrice: 0xba43b7400

gasUsed: 0x5fe3

humanReadable: null

key: null

input: 0xcfae3217

logs: []

logsBloom: 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

nonce: 0x3c2

senderTxHash: 0xb04136d9704df78a49e54e9f9ae61df4d39dc5c249aba84bc1a4e4cdc64b00eb

signature: []

status: 0x1

txError: null

to: 0xc58294ecde8fdb288fd845e7a43a56564b597bdb

transactionHash: 0xb04136d9704df78a49e54e9f9ae61df4d39dc5c249aba84bc1a4e4cdc64b00eb

transactionIndex: 0x1

type: TxTypeSmartContractExecution

typeInt: 48

value: 0x0

}

TxType : SMART_CONTRACT_EXECUTION