org.klomp.snark

Class PartialPiece

java.lang.Object

org.klomp.snark.PartialPiece

All Implemented Interfaces:

Comparable<PartialPiece>

class PartialPiece
extends Object
implements Comparable<PartialPiece>

Represents a piece of a torrent being downloaded, storing partial data either on the heap or in a temporary file if the piece is large.

Handles out-of-order chunk reception and manages a BitField tracking received chunks. Implements Comparable for prioritization by piece number and completeness.

Usage Notes: - Not thread-safe except for synchronized public methods. - Objects for the same piece should not be shared between peers. - Used extensively by PeerCoordinator and PeerState for request management.

Constructor Summary

Constructors

Constructor and Description
PartialPiece(Piece piece, int len, File tempDir) Constructs a PartialPiece for the given piece with specified length.

Method Summary

Modifier and Type	Method and Description
int	compareTo(PartialPiece other) Compares this piece with another by piece number, highest priority first, then by highest downloaded first.
boolean	equals(Object o) Equality based on piece ID only.
int	getDownloaded() Returns the total number of bytes downloaded in this piece, accurately accounting for holes.
byte[]	getHash() Computes and returns the SHA1 hash of the complete piece data.
int	getLength() Returns the length of the piece in bytes.
int	getPiece() Returns the piece number.
Request	getRequest() Creates a Request object for the next missing chunk in this piece.
boolean	hasChunk(int chunk) Checks if the given chunk index has been downloaded.
boolean	hasData() Checks if any chunks of this piece have been downloaded.
int	hashCode()
static void	info(String s) Logs an info message for this class.
boolean	isComplete() Checks if the entire piece has been downloaded.
void	read(DataInputStream din, int offset, int len, BandwidthListener bwl) Reads data from the input stream into this piece starting at offset.
void	release() Releases temporary file and resources associated with this piece.
String	toString()
static void	warn(String s) Logs a warning message for this class.
void	write(DataOutput out, int offset, int len) Writes piece data from the given offset and length to the output.

Methods inherited from class java.lang.Object

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

Constructor Detail

PartialPiece

public PartialPiece(Piece piece,
                    int len,
                    File tempDir)

Constructs a PartialPiece for the given piece with specified length. If piece length exceeds threshold or memory is constrained, stores on disk.

Parameters:

piece - The Piece identifier object

len - Length of this piece in bytes (must match piece length)

tempDir - Directory for temporary file storage if needed

Method Detail

compareTo

public int compareTo(PartialPiece other)

Compares this piece with another by piece number, highest priority first, then by highest downloaded first.

Specified by:

compareTo in interface Comparable<PartialPiece>

Parameters:

other - the other PartialPiece to compare to

Returns:

negative if this piece has higher priority, positive if lower, zero if equal

equals

public boolean equals(Object o)

Equality based on piece ID only.

Overrides:

equals in class Object

Parameters:

o - Object to compare

Returns:

true if representing the same piece ID, else false

getDownloaded

public int getDownloaded()

Returns the total number of bytes downloaded in this piece, accurately accounting for holes.

Returns:

number of bytes downloaded

getHash

public byte[] getHash()
               throws IOException

Computes and returns the SHA1 hash of the complete piece data. Caller must ensure piece completeness and synchronize before calling.

Returns:

byte[] SHA1 digest of piece data

Throws:

IOException - if data is incomplete or read fails

getLength

public int getLength()

Returns the length of the piece in bytes.

Returns:

piece length

getPiece

public int getPiece()

Returns the piece number.

Returns:

piece number identifier

getRequest

public Request getRequest()

Creates a Request object for the next missing chunk in this piece. Returns null if the entire piece is complete.

Returns:

the next Request for downloading or null if complete

hasChunk

public boolean hasChunk(int chunk)

Checks if the given chunk index has been downloaded.

Parameters:

chunk - zero-based chunk index

Returns:

true if chunk downloaded, false otherwise

hasData

public boolean hasData()

Checks if any chunks of this piece have been downloaded.

Returns:

true if any data present, false if none

hashCode

public int hashCode()

Overrides:

hashCode in class Object

info

public static void info(String s)

Logs an info message for this class.

Parameters:

s - info message string

isComplete

public boolean isComplete()

Checks if the entire piece has been downloaded.

Returns:

true if complete, else false

read

public void read(DataInputStream din,
                 int offset,
                 int len,
                 BandwidthListener bwl)
          throws IOException

Reads data from the input stream into this piece starting at offset. Marks chunks as downloaded in the bitfield. Handles out-of-order chunks by logging warnings.

Parameters:

din - input stream to read from

offset - offset to read into the piece (must be multiple of chunk size)

len - length of data to read

bwl - bandwidth listener to report downloaded bytes

Throws:

IOException - on I/O errors or incorrect offset

release

public void release()

Releases temporary file and resources associated with this piece. Safe to call multiple times.

toString

public String toString()

Overrides:

toString in class Object

warn

public static void warn(String s)

Logs a warning message for this class.

Parameters:

s - warning message string

write

public void write(DataOutput out,
                  int offset,
                  int len)
           throws IOException

Writes piece data from the given offset and length to the output. Caller must synchronize on the output stream and piece for thread safety.

Parameters:

out - destination output to write data to

offset - offset in this piece to start writing from

len - length of data to write

Throws:

IOException - on I/O failure