Class Filter


  • public class Filter
    extends Object
    The `Filter` trait defines behavior for indicating chain activity of interest pertaining to channels. This is useful in order to have a [`Watch`] implementation convey to a chain source which transactions to be notified of. Notification may take the form of pre-filtering blocks or, in the case of [BIP 157]/[BIP 158], only fetching a block if the compact filter matches. If receiving full blocks from a chain source, any further filtering is unnecessary. After an output has been registered, subsequent block retrievals from the chain source must not exclude any transactions matching the new criteria nor any in-block descendants of such transactions. Note that use as part of a [`Watch`] implementation involves reentrancy. Therefore, the `Filter` should not block on I/O. Implementations should instead queue the newly monitored data to be processed later. Then, in order to block until the data has been processed, any [`Watch`] invocation that has called the `Filter` must return [`TemporaryFailure`]. [`TemporaryFailure`]: channelmonitor::ChannelMonitorUpdateErr::TemporaryFailure [BIP 157]: https://github.com/bitcoin/bips/blob/master/bip-0157.mediawiki [BIP 158]: https://github.com/bitcoin/bips/blob/master/bip-0158.mediawiki
    • Method Detail

      • register_tx

        public void register_tx​(byte[] txid,
                                byte[] script_pubkey)
        Registers interest in a transaction with `txid` and having an output with `script_pubkey` as a spending condition.
      • register_output

        public Option_C2Tuple_usizeTransactionZZ register_output​(WatchedOutput output)
        Registers interest in spends of a transaction output. Optionally, when `output.block_hash` is set, should return any transaction spending the output that is found in the corresponding block along with its index. This return value is useful for Electrum clients in order to supply in-block descendant transactions which otherwise were not included. This is not necessary for other clients if such descendant transactions were already included (e.g., when a BIP 157 client provides the full block).