VersionMessage (core 0.15 API)

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 Summary

Fields
Modifier and Type	Field and Description
`long`	`bestHeight` How many blocks are in the chain, according to the other side.
`static java.lang.String`	`BITCOINJ_VERSION` The version of this library release, as a string.
`int`	`clientVersion` The version number of the protocol spoken.
`PeerAddress`	`fromAddr` The network address of the node emitting this message.
`static java.lang.String`	`LIBRARY_SUBVER` The value that is prepended to the subVer field of this application.
`long`	`localServices` Flags defining what optional services are supported.
`static int`	`NODE_BITCOIN_CASH` A service bit used by Bitcoin-ABC to announce Bitcoin Cash nodes.
`static int`	`NODE_BLOOM` A service bit that denotes whether the peer supports BIP37 bloom filters or not.
`static int`	`NODE_GETUTXOS` A service bit that denotes whether the peer supports the getutxos message or not.
`static int`	`NODE_NETWORK` A service bit that denotes whether the peer has a full copy of the block chain or not.
`static int`	`NODE_NETWORK_LIMITED` A service bit that denotes whether the peer has at least the last two days worth of blockchain (BIP159).
`static int`	`NODE_WITNESS` Indicates that a node can be asked for blocks and transactions including witness data.
`PeerAddress`	`receivingAddr` The network address of the node receiving this message.
`boolean`	`relayTxesBeforeFilter` Whether or not to relay tx invs before a filter is received.
`java.lang.String`	`subVer` User-Agent as defined in BIP 14.
`long`	`time` What the other side believes the current time to be, in seconds.

Fields inherited from class org.bitcoinj.core.Message
cursor, length, MAX_SIZE, offset, params, payload, protocolVersion, recached, serializer, UNKNOWN_LENGTH

Constructor Summary

Constructors
Constructor and Description
`VersionMessage(NetworkParameters params, byte[] payload)`
`VersionMessage(NetworkParameters params, int newBestHeight)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`appendToSubVer(java.lang.String name, java.lang.String version, java.lang.String comments)` Appends the given user-agent information to the subVer field.
`void`	`bitcoinSerializeToStream(java.io.OutputStream buf)` Serializes this message to the provided stream.
`VersionMessage`	`duplicate()`
`boolean`	`equals(java.lang.Object o)`
`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).
`int`	`hashCode()`
`boolean`	`hasLimitedBlockChain()` Returns true if the peer has at least the last two days worth of blockchain (BIP159).
`boolean`	`isBloomFilteringSupported()` Returns true if the peer supports bloom filtering according to BIP37 and BIP111.
`boolean`	`isGetUTXOsSupported()` Returns true if the protocol version and service bits both indicate support for the getutxos message.
`boolean`	`isPingPongSupported()` Returns true if the clientVersion field is `NetworkParameters.ProtocolVersion.PONG` or higher.
`boolean`	`isWitnessSupported()` Returns true if a peer can be asked for blocks and transactions including witness data.
`protected void`	`parse()`
`java.lang.String`	`toString()`

Methods inherited from class org.bitcoinj.core.Message
adjustLength, bitcoinSerialize, bitcoinSerialize, getHash, getMessageSize, getParams, hasMoreBytes, isCached, isRecached, readByteArray, readBytes, readHash, readInt64, readStr, readUint32, readUint64, readVarInt, readVarInt, unCache, unsafeBitcoinSerialize

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- 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
  - 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:
    
    Constant Field Values
  - NODE_GETUTXOS
```
public static final int NODE_GETUTXOS
```
    A service bit that denotes whether the peer supports the getutxos message or not.
    
    See Also:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - NODE_WITNESS
```
public static final int NODE_WITNESS
```
    Indicates that a node can be asked for blocks and transactions including witness data.
    
    See Also:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - NODE_BITCOIN_CASH
```
public static final int NODE_BITCOIN_CASH
```
    A service bit used by Bitcoin-ABC to announce Bitcoin Cash nodes.
    
    See Also:
    
    Constant Field Values
  - 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 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,
                      byte[] payload)
               throws ProtocolException
```
    Throws:
    
    ProtocolException
  - VersionMessage
```
public VersionMessage(NetworkParameters params,
                      int newBestHeight)
```
- Method Detail
  - parse
```
protected void parse()
              throws ProtocolException
```
    Specified by:
    
    parse in class Message
    
    Throws:
    
    ProtocolException
  - bitcoinSerializeToStream
```
public void bitcoinSerializeToStream(java.io.OutputStream buf)
                              throws java.io.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:
    
    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
  - duplicate
```
public VersionMessage duplicate()
```
  - 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
```
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).

Class VersionMessage

Field Summary

Fields inherited from class org.bitcoinj.core.Message

Constructor Summary

Method Summary

Methods inherited from class org.bitcoinj.core.Message

Methods inherited from class java.lang.Object

Field Detail

BITCOINJ_VERSION

LIBRARY_SUBVER

NODE_NETWORK

NODE_GETUTXOS

NODE_BLOOM

NODE_WITNESS

NODE_NETWORK_LIMITED

NODE_BITCOIN_CASH

clientVersion

localServices

time

receivingAddr

fromAddr

subVer

bestHeight

relayTxesBeforeFilter

Constructor Detail

VersionMessage

VersionMessage

Method Detail

parse

bitcoinSerializeToStream

equals

hashCode

toString

duplicate

appendToSubVer

isPingPongSupported

isBloomFilteringSupported

isGetUTXOsSupported

isWitnessSupported

hasBlockChain

hasLimitedBlockChain