Package org.bitcoinj.core

Class VersionMessage

  • All Implemented Interfaces:
    Message
    public class VersionMessage
extends BaseMessage

    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 Detail

      • BITCOINJ_VERSION

        public static final java.lang.String BITCOINJ_VERSION
        The version of this library release, as a string.
        See Also:
        Constant Field Values

      • LIBRARY_SUBVER

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

      • clientVersion

        public int clientVersion
        The version number of the protocol spoken.

      • localServices

        public Services localServices
        Flags defining what optional services are supported.

      • time

        public java.time.Instant time
        What the other side believes the current time to be.

      • receivingServices

        public Services receivingServices
        The services supported by the receiving node as perceived by the transmitting node.

      • receivingAddr

        public java.net.InetSocketAddress receivingAddr
        The network address of the receiving node as perceived by the transmitting node

      • subVer

        public java.lang.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 Detail

      • VersionMessage

        public VersionMessage​(NetworkParameters params,
                      int bestHeight)
        Construct own version message from given NetworkParameters and our best height of the chain.
        Parameters:
        params - network parameters to construct own version message from
        bestHeight - our best height to announce

    • Method Detail

      • read

        public static VersionMessage read​(java.nio.ByteBuffer payload)
                           throws java.nio.BufferUnderflowException,
                                  ProtocolException
        Deserialize this message from a given payload.
        Parameters:
        payload - payload to deserialize from
        Returns:
        read message
        Throws:
        java.nio.BufferUnderflowException - if the read message extends beyond the remaining bytes of the payload
        ProtocolException

      • clientVersion

        public int clientVersion()
        Gets the client version.
        Returns:
        client version

      • services

        public Services services()
        Get the service bitfield that represents the node services being provided.
        Returns:
        service bitfield

      • bitcoinSerializeToStream

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

      • equals

        public boolean equals​(java.lang.Object o)
        Overrides:
        equals in class java.lang.Object

      • hashCode

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

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • appendToSubVer

        public void appendToSubVer​(java.lang.String name,
                           java.lang.String version,
                           @Nullable
                           java.lang.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:
        java.lang.IllegalArgumentException - if name, version or comments contains invalid characters.

      • isPingPongSupported

        @Deprecated
public boolean isPingPongSupported()
        Deprecated.
        just assume Ping and Pong are supported