Package org.bitcoinj.core

Class VersionMessage

java.lang.Object
org.bitcoinj.core.Message
org.bitcoinj.core.VersionMessage
public class VersionMessage extends Message

A VersionMessage holds information exchanged during connection setup with another peer. Most of the fields are not particularly interesting. The subVer field, since BIP 14, acts as a User-Agent string would. You can and should append to or change the subVer for your own software so other implementations can identify it, and you can look at the subVer field received from other nodes to see what they are running.

After creating yourself a VersionMessage, you can pass it to PeerGroup.setVersionMessage(VersionMessage) to ensure it will be used for each new connection.

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

  • Field Details

    • BITCOINJ_VERSION

      public static final String BITCOINJ_VERSION
      The version of this library release, as a string.
      See Also:

    • LIBRARY_SUBVER

      public static final String LIBRARY_SUBVER
      The value that is prepended to the subVer field of this application.
      See Also:

    • NODE_NETWORK

      public static final int NODE_NETWORK
      A service bit that denotes whether the peer has a full copy of the block chain or not.
      See Also:

    • NODE_GETUTXOS

      public static final int NODE_GETUTXOS
      A service bit that denotes whether the peer supports the getutxos message or not.
      See Also:

    • NODE_BLOOM

      public static final int NODE_BLOOM
      A service bit that denotes whether the peer supports BIP37 bloom filters or not. The service bit is defined in BIP111.
      See Also:

    • NODE_WITNESS

      public static final int NODE_WITNESS
      Indicates that a node can be asked for blocks and transactions including witness data.
      See Also:

    • NODE_NETWORK_LIMITED

      public static final int NODE_NETWORK_LIMITED
      A service bit that denotes whether the peer has at least the last two days worth of blockchain (BIP159).
      See Also:

    • NODE_BITCOIN_CASH

      public static final int NODE_BITCOIN_CASH
      A service bit used by Bitcoin-ABC to announce Bitcoin Cash nodes.
      See Also:

    • clientVersion

      public int clientVersion
      The version number of the protocol spoken.

    • localServices

      public long localServices
      Flags defining what optional services are supported.

    • time

      public long time
      What the other side believes the current time to be, in seconds.

    • receivingAddr

      public PeerAddress receivingAddr
      The network address of the node receiving this message.

    • fromAddr

      public PeerAddress fromAddr
      The network address of the node emitting this message. Not used.

    • subVer

      public String subVer
      User-Agent as defined in BIP 14. Bitcoin Core sets it to something like "/Satoshi:0.9.1/".

    • bestHeight

      public long bestHeight
      How many blocks are in the chain, according to the other side.

    • relayTxesBeforeFilter

      public boolean relayTxesBeforeFilter
      Whether or not to relay tx invs before a filter is received. See BIP 37.

  • Constructor Details

  • Method Details

    • parse

      protected void parse() throws ProtocolException
      Specified by:
      parse in class Message
      Throws:
      ProtocolException

    • bitcoinSerializeToStream

      public void bitcoinSerializeToStream(OutputStream buf) throws IOException
      Description copied from class: Message
      Serializes this message to the provided stream. If you just want the raw bytes use bitcoinSerialize().
      Overrides:
      bitcoinSerializeToStream in class Message
      Throws:
      IOException

    • equals

      public boolean equals(Object o)
      Overrides:
      equals in class Object

    • hashCode

      public int hashCode()
      Overrides:
      hashCode in class Object

    • toString

      public String toString()
      Overrides:
      toString in class Object

    • duplicate

      public VersionMessage duplicate()

    • appendToSubVer

      public void appendToSubVer(String name, String version, @Nullable String comments)

      Appends the given user-agent information to the subVer field. The subVer is composed of a series of name:version pairs separated by slashes in the form of a path. For example a typical subVer field for bitcoinj users might look like "/bitcoinj:0.13/MultiBit:1.2/" where libraries come further to the left.

      There can be as many components as you feel a need for, and the version string can be anything, but it is recommended to use A.B.C where A = major, B = minor and C = revision for software releases, and dates for auto-generated source repository snapshots. A valid subVer begins and ends with a slash, therefore name and version are not allowed to contain such characters.

      Anything put in the "comments" field will appear in brackets and may be used for platform info, or anything else. For example, calling appendToSubVer("MultiBit", "1.0", "Windows") will result in a subVer being set of "/bitcoinj:1.0/MultiBit:1.0(Windows)/". Therefore the / ( and ) characters are reserved in all these components. If you don't want to add a comment (recommended), pass null.

      See BIP 14 for more information.

      Parameters:
      comments - Optional (can be null) platform or other node specific information.
      Throws:
      IllegalArgumentException - if name, version or comments contains invalid characters.

    • isPingPongSupported

      public boolean isPingPongSupported()
      Returns true if the clientVersion field is NetworkParameters.ProtocolVersion.PONG or higher. If it is then Peer.ping() is usable.

    • isBloomFilteringSupported

      public boolean isBloomFilteringSupported()
      Returns true if the peer supports bloom filtering according to BIP37 and BIP111.

    • isGetUTXOsSupported

      public boolean isGetUTXOsSupported()
      Returns true if the protocol version and service bits both indicate support for the getutxos message.

    • isWitnessSupported

      public boolean isWitnessSupported()
      Returns true if a peer can be asked for blocks and transactions including witness data.

    • hasBlockChain

      public boolean hasBlockChain()
      Returns true if the version message indicates the sender has a full copy of the block chain, or false if it's running in client mode (only has the headers).

    • hasLimitedBlockChain

      public boolean hasLimitedBlockChain()
      Returns true if the peer has at least the last two days worth of blockchain (BIP159).

    • toStringServices

      public static String toStringServices(long services)