Class UTXOsMessage

  • public class UTXOsMessage
    extends Message

    Message representing a list of unspent transaction outputs ("utxos"), returned in response to sending a GetUTXOsMessage ("getutxos"). Note that both this message and the query that generates it are not supported by Bitcoin Core. An implementation is available in Bitcoin XT, a patch set on top of Core. Thus if you want to use it, you must find some XT peers to connect to. This can be done using a HttpDiscovery class combined with an HTTP/Cartographer seed.

    The getutxos/utxos protocol is defined in BIP 65. In that document you can find a discussion of the security of this protocol (briefly, there is none). Because the data found in this message is not authenticated it should be used carefully. Places where it can be useful are if you're querying your own trusted node, if you're comparing answers from multiple nodes simultaneously and don't believe there is a MITM on your connection, or if you're only using the returned data as a UI hint and it's OK if the data is occasionally wrong. Bear in mind that the answer can be wrong even in the absence of malicious intent just through the nature of querying an ever changing data source: the UTXO set may be updated by a new transaction immediately after this message is returned.

    Instances of this class are not safe for use by multiple threads.

    • Field Detail


        public static long MEMPOOL_HEIGHT
        This is a special sentinel value that can appear in the heights field if the given tx is in the mempool.
    • Constructor Detail

      • UTXOsMessage

        public UTXOsMessage​(NetworkParameters params,
                            byte[] payloadBytes)
      • UTXOsMessage

        public UTXOsMessage​(NetworkParameters params,
                            java.util.List<TransactionOutput> outputs,
                            long[] heights,
                            Sha256Hash chainHead,
                            long height)
        Provide an array of output objects, with nulls indicating that the output was missing. The bitset will be calculated from this.
    • Method Detail

      • bitcoinSerializeToStream

        protected void bitcoinSerializeToStream​( stream)
        Description copied from class: Message
        Serializes this message to the provided stream. If you just want the raw bytes use bitcoinSerialize().
        bitcoinSerializeToStream in class Message
      • getHitMap

        public byte[] getHitMap()
        Returns a bit map indicating which of the queried outputs were found in the UTXO set.
      • getOutputs

        public java.util.List<TransactionOutput> getOutputs()
        Returns the list of outputs that matched the query.
      • getHeights

        public long[] getHeights()
        Returns the block heights of each output returned in getOutputs(), or MEMPOOL_HEIGHT if not confirmed yet.
      • toString

        public java.lang.String toString()
        toString in class java.lang.Object
      • equals

        public boolean equals​(java.lang.Object o)
        equals in class java.lang.Object
      • hashCode

        public int hashCode()
        hashCode in class java.lang.Object