Cancel

TxTypeCancel cancels the execution of the transaction with the same nonce in the transaction pool. This transaction type is useful when a submitted transaction seems unprocessed for a certain amount of time.

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

Create a Web3j instance with the specified BAOBAB_URL

Creating new credentials using LEGACY_KEY_privkey

Gas price and gas limit settings

Set the sender's from address

Get the chain ID from the network

Getting the nonce for the sender's address

Set the transaction type to CANCEL

Create a raw transaction for canceling pending transaction

Sign the raw transaction with pre-defined credentials

Send the raw transaction to the blockchain. It will return the transaction hash

Get the transaction receipt and using the transaction hash

Shutdown the web3j instance

Decoding the raw transaction to get the transaction type

cancelTransactionExample.java

package org.web3j.example.transactions;

import org.web3j.tx.response.PollingTransactionReceiptProcessor;

import org.web3j.tx.response.TransactionReceiptProcessor;

import org.web3j.example.keySample;

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.TxTypeCancel;

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;

/**

*

*/

public class CancelExample 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 = keySample.LEGACY_KEY_address;

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

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

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

.getTransactionCount();

TxType.Type type = Type.CANCEL;

KlayRawTransaction raw = KlayRawTransaction.createTransaction(

type,

nonce,

GAS_PRICE,

GAS_LIMIT,

from);

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();

TxTypeCancel rawTransaction = TxTypeCancel.decodeFromRawTransaction(signedMessage);

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

}

}

output

❯ java cancelTransactionExample.java

TxHash :

0x3b739ef7094ff05af24322dc0d0547aecaaea0bad69c89129f159c7f03e38b3d

receipt :

class TransactionReceipt {

blockHash: 0x05402b8b900d619380a723f417ec56de8843e92078f7160c13ede20f98cfd8a5

blockNumber: 0x8dea897

codeFormat: null

contractAddress: null

feePayer: null

feePayerSignatures: []

feeRatio: null

from: 0xa2a8854b1802d8cd5de631e690817c253d6a9153

gas: 0x66919e

effectiveGasPrice: 0x5d21dba00

gasPrice: 0xba43b7400

gasUsed: 0x5208

humanReadable: null

key: null

input: null

logs: []

logsBloom: 0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

nonce: 0x3bd

senderTxHash: 0x3b739ef7094ff05af24322dc0d0547aecaaea0bad69c89129f159c7f03e38b3d

signature: []

status: 0x1

txError: null

to: null

transactionHash: 0x3b739ef7094ff05af24322dc0d0547aecaaea0bad69c89129f159c7f03e38b3d

transactionIndex: 0x1

type: TxTypeCancel

typeInt: 56

value: null

}

TxType : CANCEL