TxBuilder

class TxBuilder

A transaction builder.

After creating the TxBuilder, you set options on it until finally calling .finish to consume the builder and generate the transaction.

Each method on the TxBuilder returns an instance of a new TxBuilder with the option set/added.

Constructors

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fun TxBuilder()

Functions

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fun addData(data: List<UByte>): TxBuilder

Add data as an output using OP_RETURN.

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fun addRecipient(script: Script, amount: ULong): TxBuilder

Add a recipient to the internal list.

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fun addUnspendable(unspendable: OutPoint): TxBuilder

Add a utxo to the internal list of unspendable utxos. It’s important to note that the "must-be-spent" utxos added with TxBuilder.addUtxo have priority over this. See the Rust docs of the two linked methods for more details.

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fun addUtxo(outpoint: OutPoint): TxBuilder

Add an outpoint to the internal list of UTXOs that must be spent. These have priority over the "unspendable" utxos, meaning that if a utxo is present both in the "utxos" and the "unspendable" list, it will be spent.

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fun addUtxos(outpoints: List<OutPoint>): TxBuilder

Add the list of outpoints to the internal list of UTXOs that must be spent. If an error occurs while adding any of the UTXOs then none of them are added and the error is returned. These have priority over the "unspendable" utxos, meaning that if a utxo is present both in the "utxos" and the "unspendable" list, it will be spent.

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fun doNotSpendChange(): TxBuilder

Do not spend change outputs. This effectively adds all the change outputs to the "unspendable" list. See TxBuilder.unspendable.

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fun drainTo(address: String): TxBuilder

Sets the address to drain excess coins to. Usually, when there are excess coins they are sent to a change address generated by the wallet. This option replaces the usual change address with an arbitrary ScriptPubKey of your choosing. Just as with a change output, if the drain output is not needed (the excess coins are too small) it will not be included in the resulting transaction. The only difference is that it is valid to use drainTo without setting any ordinary recipients with addRecipient (but it is perfectly fine to add recipients as well). If you choose not to set any recipients, you should either provide the utxos that the transaction should spend via addUtxos, or set drainWallet to spend all of them. When bumping the fees of a transaction made with this option, you probably want to use BumpFeeTxBuilder.allowShrinking to allow this output to be reduced to pay for the extra fees.

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fun drainWallet(): TxBuilder

Spend all the available inputs. This respects filters like TxBuilder.unspendable and the change policy.

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fun enableRbf(): TxBuilder

Enable signaling RBF. This will use the default nsequence value of 0xFFFFFFFD.

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fun enableRbfWithSequence(nsequence: UInt): TxBuilder

Enable signaling RBF with a specific nSequence value. This can cause conflicts if the wallet's descriptors contain an "older" (OP_CSV) operator and the given nsequence is lower than the CSV value. If the nsequence is higher than 0xFFFFFFFD an error will be thrown, since it would not be a valid nSequence to signal RBF.

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fun feeAbsolute(feeAmount: ULong): TxBuilder

Set an absolute fee.

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fun feeRate(satPerVbyte: Float): TxBuilder

Set a custom fee rate.

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fun finish(wallet: Wallet): TxBuilderResult

Finish building the transaction. Returns a TxBuilderResult.

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fun manuallySelectedOnly(): TxBuilder

Only spend utxos added by add_utxo. The wallet will not add additional utxos to the transaction even if they are needed to make the transaction valid.

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fun onlySpendChange(): TxBuilder

Only spend change outputs. This effectively adds all the non-change outputs to the "unspendable" list. See TxBuilder.unspendable.

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fun setRecipients(recipients: List<<Error class: unknown class>>): TxBuilder

Set the list of recipients by providing a list of AddressAmount.

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fun unspendable(unspendable: List<OutPoint>): TxBuilder

Replace the internal list of unspendable utxos with a new list. It’s important to note that the "must-be-spent" utxos added with TxBuilder.addUtxo have priority over these. See the Rust docs of the two linked methods for more details.