io.neow3j.contract.FungibleToken Maven / Gradle / Ivy
package io.neow3j.contract;
import io.neow3j.contract.exceptions.UnexpectedReturnTypeException;
import io.neow3j.protocol.Neow3j;
import io.neow3j.script.ScriptBuilder;
import io.neow3j.transaction.ContractSigner;
import io.neow3j.transaction.TransactionBuilder;
import io.neow3j.types.ContractParameter;
import io.neow3j.types.Hash160;
import io.neow3j.wallet.Account;
import io.neow3j.wallet.Wallet;
import java.io.IOException;
import java.math.BigInteger;
import java.util.List;
import static io.neow3j.transaction.AccountSigner.calledByEntry;
import static io.neow3j.types.ContractParameter.hash160;
import static io.neow3j.types.ContractParameter.integer;
import static java.util.Arrays.asList;
/**
* Represents a fungible token contract that is compliant with the NEP-17 standard and provides
* methods to invoke it.
*/
public class FungibleToken extends Token {
private static final String BALANCE_OF = "balanceOf";
private static final String TRANSFER = "transfer";
/**
* Constructs a new {@code FungibleToken} representing the token contract with the given script
* hash. Uses the given {@link Neow3j} instance for all invocations.
*
* @param scriptHash the token contract's script hash
* @param neow the {@link Neow3j} instance to use for invocations.
*/
public FungibleToken(Hash160 scriptHash, Neow3j neow) {
super(scriptHash, neow);
}
/**
* Gets the token balance for the given account.
*
* The token amount is returned in token fractions. E.g., an amount of 1 GAS is returned as
* 1*10^8 GAS fractions.
*
* The balance is not cached locally. Every time this method is called requests are sent to the
* Neo node.
*
* @param account the account to fetch the balance for.
* @return the token balance.
* @throws IOException if there was a problem fetching information from the
* Neo node.
* @throws UnexpectedReturnTypeException if the contract invocation did not return something
* interpretable as a number.
*/
public BigInteger getBalanceOf(Account account) throws IOException,
UnexpectedReturnTypeException {
return getBalanceOf(account.getScriptHash());
}
/**
* Gets the token balance for the given account script hash.
*
* The token amount is returned in token fractions. E.g., an amount of 1 GAS is returned as
* 1*10^8 GAS fractions.
*
* The balance is not cached locally. Every time this method is called requests are sent to the
* Neo node.
*
* @param scriptHash the script hash of the account to fetch the balance for.
* @return the token balance.
* @throws IOException if there was a problem fetching information from the
* Neo node.
* @throws UnexpectedReturnTypeException if the contract invocation did not return something
* interpretable as a number.
*/
public BigInteger getBalanceOf(Hash160 scriptHash) throws IOException,
UnexpectedReturnTypeException {
ContractParameter ofParam = hash160(scriptHash);
return callFuncReturningInt(BALANCE_OF, ofParam);
}
/**
* Gets the token balance for the given wallet, i.e., all accounts in the wallet.
*
* The token amount is returned in token fractions. E.g., an amount of 1 GAS is returned as
* 1*10^8 GAS fractions.
*
* The balance is not cached locally. Every time this method is called requests are sent to the
* Neo node.
*
* @param wallet the wallet to fetch the balance for.
* @return the token balance.
* @throws IOException if there was a problem fetching information from the
* Neo node.
* @throws UnexpectedReturnTypeException if the contract invocation did not return something
* interpretable as a number.
*/
public BigInteger getBalanceOf(Wallet wallet) throws IOException,
UnexpectedReturnTypeException {
BigInteger sum = BigInteger.ZERO;
for (Account a : wallet.getAccounts()) {
sum = sum.add(getBalanceOf(a.getScriptHash()));
}
return sum;
}
/**
* Creates a transfer transaction.
*
* The {@code from} account is set as a signer of the transaction.
*
* @param from the sender account.
* @param to the address of the receiver.
* @param amount the amount to transfer in token fractions.
* @return a transaction builder ready for signing.
* @throws IOException if there was a problem fetching information from the Neo node.
*/
public TransactionBuilder transfer(Account from, Hash160 to, BigInteger amount)
throws IOException {
return transfer(from, to, amount, null);
}
/**
* Creates a transfer transaction.
*
* The {@code from} account is set as a signer of the transaction.
*
* Only use this method when the receiver is a deployed smart contract to avoid unnecessary
* additional fees. Otherwise, use the method without a contract parameter for data.
*
* @param from the sender account.
* @param to the script hash of the receiver.
* @param amount the amount to transfer in token fractions.
* @param data the data that is passed to the {@code onPayment} method if the receiver is a
* contract.
* @return a transaction builder ready for signing.
* @throws IOException if there was a problem fetching information from the Neo node.
*/
public TransactionBuilder transfer(Account from, Hash160 to, BigInteger amount,
ContractParameter data) throws IOException {
return transfer(from.getScriptHash(), to, amount, data).signers(calledByEntry(from));
}
/**
* Creates a transfer transaction.
*
* No signers are set on the returned transaction builder. It is up to you to set the correct
* ones, e.g., a {@link ContractSigner} in case the {@code from} address is a contract.
*
* @param from the sender hash.
* @param to the hash of the receiver.
* @param amount the amount to transfer in token fractions.
* @return a transaction builder.
* @throws IOException if there was a problem fetching information from the Neo node.
*/
public TransactionBuilder transfer(Hash160 from, Hash160 to, BigInteger amount)
throws IOException {
return transfer(from, to, amount, null);
}
/**
* Creates a transfer transaction.
*
* No signers are set on the returned transaction builder. It is up to you to set the correct
* ones, e.g., a {@link ContractSigner} in case the {@code from} address is a contract.
*
* @param from the sender account.
* @param to the script hash of the receiver.
* @param amount the amount to transfer in token fractions.
* @param data the data that is passed to the {@code onPayment} method if the receiver is a
* contract.
* @return a transaction builder ready for signing.
* @throws IOException if there was a problem fetching information from the Neo node.
*/
public TransactionBuilder transfer(Hash160 from, Hash160 to, BigInteger amount,
ContractParameter data) throws IOException {
if (amount.signum() < 0) {
throw new IllegalArgumentException("The amount must be greater than or equal to 0");
}
byte[] transferScript = buildSingleTransferScript(from, to, amount, data);
return new TransactionBuilder(neow3j).script(transferScript);
}
private byte[] buildSingleTransferScript(Hash160 from, Hash160 to, BigInteger amount,
ContractParameter data) {
List params;
params = asList(hash160(from), hash160(to), integer(amount), data);
return new ScriptBuilder().contractCall(scriptHash, TRANSFER, params).toArray();
}
}