org.klomp.snark.bencode

Class BEncoder

java.lang.Object

org.klomp.snark.bencode.BEncoder

public class BEncoder
extends Object

Converts Java objects to bencoded format for BitTorrent protocol communication.

Bencoding is a simple way to structure data used in BitTorrent. This class provides static methods to encode the following Java types:

• Strings - encoded as UTF-8 byte strings with length prefix
• byte[] - encoded as raw byte strings with length prefix
• Numbers - encoded as integer values with 'i' prefix and 'e' suffix
• List - encoded as ordered sequences starting with 'l' and ending with 'e'
• Map - encoded as dictionaries with sorted keys, starting with 'd' and ending with 'e'
• BEValue - unwrapped and encoded according to its contained type

Example output formats:

• String "hello" → "5:hello"
• Number 42 → "i42e"
• List ["a", "b"] → "l1:a1:be"
• Map {"key":"value"} → "d3:key5:valuee"

Constructor Summary

Constructors

Constructor and Description
BEncoder()

Method Summary

Modifier and Type	Method and Description
static void	bencode(byte[] bs, OutputStream out) Bencode a byte array to the given OutputStream.
static void	bencode(List<?> l, OutputStream out) Bencode a List to the given OutputStream.
static byte[]	bencode(Map<?,?> m) Bencode a Map to a byte array.
static void	bencode(Map<?,?> m, OutputStream out) Bencode a Map to the given OutputStream.
static void	bencode(Number n, OutputStream out) Bencode a Number to the given OutputStream.
static void	bencode(Object o, OutputStream out) Bencode an object to the given OutputStream.
static void	bencode(String s, OutputStream out) Bencode a String to the given OutputStream.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

BEncoder

public BEncoder()

Method Detail

bencode

public static void bencode(byte[] bs,
                           OutputStream out)
                    throws IOException

Bencode a byte array to the given OutputStream.

Parameters:

bs - the byte array to encode

out - the OutputStream to write the bencoded data to

Throws:

IOException - if an I/O error occurs

bencode

public static void bencode(List<?> l,
                           OutputStream out)
                    throws IOException

Bencode a List to the given OutputStream.

Parameters:

l - the List to encode

out - the OutputStream to write the bencoded data to

Throws:

IOException - if an I/O error occurs

bencode

public static byte[] bencode(Map<?,?> m)

Bencode a Map to a byte array. Keys must be Strings or (supported as of 0.9.31) byte[]s. A mix in the same Map is not supported.

Parameters:

m - the Map to encode

Returns:

the bencoded byte array

Throws:

IllegalArgumentException - if keys are not all Strings or all byte[]s

bencode

public static void bencode(Map<?,?> m,
                           OutputStream out)
                    throws IOException,
                           IllegalArgumentException

Bencode a Map to the given OutputStream. Keys must be Strings or (supported as of 0.9.31) byte[]s. A mix in the same Map is not supported.

Parameters:

m - the Map to encode

out - the OutputStream to write the bencoded data to

Throws:

IOException - if an I/O error occurs

IllegalArgumentException - if keys are not all Strings or all byte[]s

bencode

public static void bencode(Number n,
                           OutputStream out)
                    throws IOException

Bencode a Number to the given OutputStream.

Parameters:

n - the Number to encode

out - the OutputStream to write the bencoded data to

Throws:

IOException - if an I/O error occurs

bencode

public static void bencode(Object o,
                           OutputStream out)
                    throws IOException,
                           IllegalArgumentException

Bencode an object to the given OutputStream.

Parameters:

o - the object to encode (String, byte[], Number, List, Map, or BEValue)

out - the OutputStream to write the bencoded data to

Throws:

IOException - if an I/O error occurs

IllegalArgumentException - if the object type cannot be encoded

NullPointerException - if the object is null

bencode

public static void bencode(String s,
                           OutputStream out)
                    throws IOException

Bencode a String to the given OutputStream.

Parameters:

s - the String to encode (will be UTF-8 encoded)

out - the OutputStream to write the bencoded data to

Throws:

IOException - if an I/O error occurs