com.google.bitcoin.core

Class VersionMessage

java.lang.Object

com.google.bitcoin.core.Message

com.google.bitcoin.core.VersionMessage

All Implemented Interfaces:

Serializable

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. If blank, it means the Satoshi client.

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

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.google.bitcoin.core.Message

Message.LazyParseException

Field Summary

Fields

Modifier and Type	Field and Description
long	bestHeight How many blocks are in the chain, according to the other side.
static String	BITCOINJ_VERSION The version of this library release, as a string.
int	clientVersion The version number of the protocol spoken.
static String	LIBRARY_SUBVER The value that is prepended to the subVer field of this application.
long	localServices Flags defining what is supported.
PeerAddress	myAddr What the other side believes the address of this program is.
static int	NODE_NETWORK A services flag that denotes whether the peer has a copy of the block chain or not.
boolean	relayTxesBeforeFilter Whether or not to relay tx invs before a filter is received
String	subVer An additional string that today the official client sets to the empty string.
PeerAddress	theirAddr What the other side believes their own address is.
long	time What the other side believes the current time to be, in seconds.

Fields inherited from class com.google.bitcoin.core.Message

bytes, checksum, cursor, length, MAX_SIZE, offset, params, parsed, parseLazy, parseRetain, protocolVersion, recached, UNKNOWN_LENGTH

Constructor Summary

Constructors

Constructor and Description
VersionMessage(NetworkParameters params, byte[] msg)
VersionMessage(NetworkParameters params, int newBestHeight) Equivalent to VersionMessage(params, newBestHeight, true)
VersionMessage(NetworkParameters params, int newBestHeight, boolean relayTxesBeforeFilter)

Method Summary

Methods

Modifier and Type	Method and Description
void	appendToSubVer(String name, String version, String comments) Appends the given user-agent information to the subVer field.
void	bitcoinSerializeToStream(OutputStream buf) Serializes this message to the provided stream.
VersionMessage	duplicate()
boolean	equals(Object o)
boolean	hasBlockChain() Returns true if the version message indicates the sender has a full copy of the block chain, or if it's running in client mode (only has the headers).
int	hashCode()
boolean	isBloomFilteringSupported() Returns true if the clientVersion field is >= FilteredBlock.MIN_PROTOCOL_VERSION.
boolean	isPingPongSupported() Returns true if the clientVersion field is >= Pong.MIN_PROTOCOL_VERSION.
void	parse()
protected void	parseLite() Perform the most minimal parse possible to calculate the length of the message.
String	toString()

Methods inherited from class com.google.bitcoin.core.Message

adjustLength, bitcoinSerialize, bitcoinSerialize, ensureParsed, getHash, getMessageSize, getParams, isCached, isParsed, isRecached, maybeParse, unCache, unsafeBitcoinSerialize

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

NODE_NETWORK

public static final int NODE_NETWORK

A services flag that denotes whether the peer has a copy of the block chain or not.

See Also:

Constant Field Values

clientVersion

public int clientVersion

The version number of the protocol spoken.

localServices

public long localServices

Flags defining what is supported. Right now NODE_NETWORK is the only flag defined.

time

public long time

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

myAddr

public PeerAddress myAddr

What the other side believes the address of this program is. Not used.

theirAddr

public PeerAddress theirAddr

What the other side believes their own address is. Not used.

subVer

public String subVer

An additional string that today the official client sets to the empty string. We treat it as something like an HTTP User-Agent header.

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

BITCOINJ_VERSION

public static final String BITCOINJ_VERSION

The version of this library release, as a string.

See Also:

Constant Field Values

LIBRARY_SUBVER

public static final String LIBRARY_SUBVER

The value that is prepended to the subVer field of this application.

See Also:

Constant Field Values

Constructor Detail

VersionMessage

public VersionMessage(NetworkParameters params,
              byte[] msg)
               throws ProtocolException

Throws:

ProtocolException

VersionMessage

public VersionMessage(NetworkParameters params,
              int newBestHeight)

Equivalent to VersionMessage(params, newBestHeight, true)

VersionMessage

public VersionMessage(NetworkParameters params,
              int newBestHeight,
              boolean relayTxesBeforeFilter)

Method Detail

parseLite

protected void parseLite()
                  throws ProtocolException

Description copied from class: Message

Perform the most minimal parse possible to calculate the length of the message. This is only required for subclasses of ChildClass as root level messages will have their length passed into the constructor.

Implementations should adhere to the following contract: If parseLazy = true the 'length' field must be set before returning. If parseLazy = false the length field must be set either within the parseLite() method OR the parse() method. The overriding requirement is that length must be set to non UNKNOWN_MESSAGE value by the time the constructor exits.

Specified by:

parseLite in class Message

Throws:

ProtocolException

parse

public void parse()
           throws ProtocolException

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().

Throws:

IOException

hasBlockChain

public boolean hasBlockChain()

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

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:0.4-SNAPSHOT/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 >= Pong.MIN_PROTOCOL_VERSION. If it is then ping() is usable.

isBloomFilteringSupported

public boolean isBloomFilteringSupported()

Returns true if the clientVersion field is >= FilteredBlock.MIN_PROTOCOL_VERSION. If it is then Bloom filtering is available and the memory pool of the remote peer will be queried when the downloadData property is true.