Message (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- org.klomp.snark.Message

```
class Message
extends Object
```
Represents a BitTorrent protocol message for peer communication.
This class encapsulates all BitTorrent protocol message types including:
- Control messages: keep-alive, choke, unchoke, interested, uninterested
- Piece messages: have, bitfield, request, piece, cancel
- Extension messages for protocol extensions
- Fast peer extension messages (BEP 6)
- DHT messages (BEP 5, BEP 52)
Messages are created and queued for sending through a DataOutputStream. The sendMessage() method translates messages to wire format.
Message structure includes:
- type - The message type byte
- piece - The piece index (for have, request, piece, cancel)
- begin - The offset within the piece
- length - The data length
- data - Optional payload data
See Also:
PeerState

Field Summary

Fields
Modifier and Type	Field and Description
`(package private) static byte`	`ALLOWED_FAST` Allow request of a piece without an unchoke (BEP 6).
`(package private) int`	`begin` The offset within the piece
`(package private) static byte`	`BITFIELD` Bitfield of pieces the peer has.
`(package private) static byte`	`CANCEL` Cancel a previously sent request.
`(package private) static byte`	`CHOKE` Stop sending piece data to the peer.
`(package private) byte[]`	`data` The data payload
`(package private) static byte`	`EXTENSION` BEP 10 extended message, sub-type in the low byte.
`(package private) static byte`	`HASH_REJECT` Reject a hash request (BEP 52).
`(package private) static byte`	`HASH_REQUEST` Request merkle hash tree data (BEP 52).
`(package private) static byte`	`HASHES` Merkle hash tree data (BEP 52).
`(package private) static byte`	`HAVE` Announce possession of a single piece.
`(package private) static byte`	`HAVE_ALL` Announce possession of every piece (BEP 6).
`(package private) static byte`	`HAVE_NONE` Announce possession of no pieces (BEP 6).
`(package private) static byte`	`INTERESTED` Signal that the peer has pieces we want.
`(package private) static byte`	`KEEP_ALIVE` No-op message sent periodically to keep the connection alive.
`(package private) int`	`len` The payload length
`(package private) int`	`length` The data length
`(package private) int`	`off` The data offset
`(package private) int`	`piece` The piece index
`(package private) static byte`	`PIECE` Chunk of a piece in response to a request.
`(package private) static byte`	`PORT` Announce the DHT listening port (BEP 5).
`(package private) static byte`	`REJECT` Reject a previously accepted request (BEP 6).
`(package private) static byte`	`REQUEST` Request a chunk of a piece.
`(package private) static byte`	`SUGGEST` Suggest a piece the peer may want (BEP 6).
`(package private) byte`	`type` The message type
`(package private) static byte`	`UNCHOKE` Resume sending piece data to the peer.
`(package private) static byte`	`UNINTERESTED` Signal that we no longer want pieces from the peer.

Constructor Summary

Constructors
Constructor and Description
`Message(byte type)` For types KEEP_ALIVE, CHOKE, UNCHOKE, INTERESTED, UNINTERESTED, HAVE_ALL, HAVE_NONE
`Message(byte[] data)` For type BITFIELD
`Message(byte type, int piece)` For types HAVE, PORT, SUGGEST, ALLOWED_FAST
`Message(byte type, int piece, int begin, int length)` For types REQUEST, REJECT, CANCEL
`Message(int id, byte[] data)` For type EXTENSION
`Message(int piece, int begin, int length, DataLoader loader)` For type PIECE with deferred data

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`(package private) boolean`	`abortIfDiscarded()` Abort a claimed-but-not-yet-started prefetch because the message was purged unsent, saving the disk read entirely.
`(package private) boolean`	`claimLoad()` Claim exclusive right to execute the loader for this message.
`(package private) void`	`completeLoad(ByteArray ba)` Deliver the result of a loader run started after `claimLoad()` returned true.
`(package private) void`	`discard()` Mark this message as dropped without sending and release any loaded buffer exactly once.
`(package private) boolean`	`isDataReady()` Whether the deferred data has been loaded and not yet released.
`(package private) boolean`	`isDiscarded()` Whether this message was dropped without sending.
`(package private) ByteArray`	`runLoader()` Invoke the deferred loader.
`(package private) boolean`	`sendMessage(DataOutputStream dos)` Sends this message through the given DataOutputStream.
`String`	`toString()` A string representation of the message.

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

- Field Detail
  - ALLOWED_FAST
```
static final byte ALLOWED_FAST
```
    Allow request of a piece without an unchoke (BEP 6).
    See Also:
    Constant Field Values
  - begin
```
final int begin
```
    The offset within the piece
  - BITFIELD
```
static final byte BITFIELD
```
    Bitfield of pieces the peer has.
    See Also:
    Constant Field Values
  - CANCEL
```
static final byte CANCEL
```
    Cancel a previously sent request.
    See Also:
    Constant Field Values
  - CHOKE
```
static final byte CHOKE
```
    Stop sending piece data to the peer.
    See Also:
    Constant Field Values
  - data
```
byte[] data
```
    The data payload
  - EXTENSION
```
static final byte EXTENSION
```
    BEP 10 extended message, sub-type in the low byte.
    See Also:
    Constant Field Values
  - HASH_REJECT
```
static final byte HASH_REJECT
```
    Reject a hash request (BEP 52).
    See Also:
    Constant Field Values
  - HASH_REQUEST
```
static final byte HASH_REQUEST
```
    Request merkle hash tree data (BEP 52).
    See Also:
    Constant Field Values
  - HASHES
```
static final byte HASHES
```
    Merkle hash tree data (BEP 52).
    See Also:
    Constant Field Values
  - HAVE
```
static final byte HAVE
```
    Announce possession of a single piece.
    See Also:
    Constant Field Values
  - HAVE_ALL
```
static final byte HAVE_ALL
```
    Announce possession of every piece (BEP 6).
    See Also:
    Constant Field Values
  - HAVE_NONE
```
static final byte HAVE_NONE
```
    Announce possession of no pieces (BEP 6).
    See Also:
    Constant Field Values
  - INTERESTED
```
static final byte INTERESTED
```
    Signal that the peer has pieces we want.
    See Also:
    Constant Field Values
  - KEEP_ALIVE
```
static final byte KEEP_ALIVE
```
    No-op message sent periodically to keep the connection alive.
    See Also:
    Constant Field Values
  - len
```
final int len
```
    The payload length
  - length
```
final int length
```
    The data length
  - off
```
final int off
```
    The data offset
  - piece
```
final int piece
```
    The piece index
  - PIECE
```
static final byte PIECE
```
    Chunk of a piece in response to a request.
    See Also:
    Constant Field Values
  - PORT
```
static final byte PORT
```
    Announce the DHT listening port (BEP 5).
    See Also:
    Constant Field Values
  - REJECT
```
static final byte REJECT
```
    Reject a previously accepted request (BEP 6).
    See Also:
    Constant Field Values
  - REQUEST
```
static final byte REQUEST
```
    Request a chunk of a piece.
    See Also:
    Constant Field Values
  - SUGGEST
```
static final byte SUGGEST
```
    Suggest a piece the peer may want (BEP 6).
    See Also:
    Constant Field Values
  - type
```
final byte type
```
    The message type
  - UNCHOKE
```
static final byte UNCHOKE
```
    Resume sending piece data to the peer.
    See Also:
    Constant Field Values
  - UNINTERESTED
```
static final byte UNINTERESTED
```
    Signal that we no longer want pieces from the peer.
    See Also:
    Constant Field Values
- Constructor Detail
  - Message
```
Message(byte type)
```
    For types KEEP_ALIVE, CHOKE, UNCHOKE, INTERESTED, UNINTERESTED, HAVE_ALL, HAVE_NONE
  - Message
```
Message(byte[] data)
```
    For type BITFIELD
  - Message
```
Message(byte type,
        int piece)
```
    For types HAVE, PORT, SUGGEST, ALLOWED_FAST
  - Message
```
Message(byte type,
        int piece,
        int begin,
        int length)
```
    For types REQUEST, REJECT, CANCEL
  - Message
```
Message(int id,
        byte[] data)
```
    For type EXTENSION
  - Message
```
Message(int piece,
        int begin,
        int length,
        DataLoader loader)
```
    For type PIECE with deferred data
- Method Detail
  - abortIfDiscarded
```
boolean abortIfDiscarded()
```
    Abort a claimed-but-not-yet-started prefetch because the message was purged unsent, saving the disk read entirely.
    Returns:
    true if the caller should skip loading; pending state is cleared either way
  - claimLoad
```
boolean claimLoad()
```
    Claim exclusive right to execute the loader for this message.
    Returns:
    true if the caller must run the loader and later call completeLoad(ByteArray); false if already claimed, completed, failed, discarded, or not loader-backed
  - completeLoad
```
void completeLoad(ByteArray ba)
```
    Deliver the result of a loader run started after claimLoad() returned true. Stores the buffer unless the message was discarded meanwhile, in which case the buffer is released immediately; failure is recorded so the sender drops the message.
    Parameters:
    ba - the loaded buffer, or null on load failure
  - discard
```
void discard()
```
    Mark this message as dropped without sending and release any loaded buffer exactly once. Called from all purge paths (choke, cancel, disconnect, queue overflow); safe to call repeatedly and concurrently with an in-flight prefetch.
  - isDataReady
```
boolean isDataReady()
```
    Whether the deferred data has been loaded and not yet released.
    Returns:
    true if ready to send without further loading
  - isDiscarded
```
boolean isDiscarded()
```
    Whether this message was dropped without sending.
    Returns:
    true if discarded
  - runLoader
```
ByteArray runLoader()
```
    Invoke the deferred loader. Must be called only after winning claimLoad(); executes with no locks held so slow reads never block purge paths.
    Returns:
    the loaded buffer, or null on error (a REJECT has already been queued upstream)
  - sendMessage
```
boolean sendMessage(DataOutputStream dos)
             throws IOException
```
    Sends this message through the given DataOutputStream.
    Parameters:
    dos - the output stream to write to
    Returns:
    true if the message was written, false if the deferred data could not be loaded and the message was dropped
    Throws:
    IOException - if an I/O error occurs
  - toString
```
public String toString()
```
    A string representation of the message.
    Overrides:
    toString in class Object
    Returns:
    a string representation of the message

Class Message

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

ALLOWED_FAST

begin

BITFIELD

CANCEL

CHOKE

data

EXTENSION

HASH_REJECT

HASH_REQUEST

HASHES

HAVE

HAVE_ALL

HAVE_NONE

INTERESTED

KEEP_ALIVE

len

length

off

piece

PIECE

PORT

REJECT

REQUEST

SUGGEST

type

UNCHOKE

UNINTERESTED

Constructor Detail

Message

Message

Message

Message

Message

Message

Method Detail

abortIfDiscarded

claimLoad

completeLoad

discard

isDataReady

isDiscarded

runLoader

sendMessage

toString