net.tomp2p.synchronization

Class RSync

java.lang.Object

net.tomp2p.synchronization.RSync

public final class RSync
extends Object

Synchronization class is responsible for efficient and optimal synchronization of data resources between responsible peer and replica peers. If one of replicas goes offline, the responsible peer transfers the value completely to the new replica peer. In case the values at responsible peer and replica peer are the same, then no data is transmitted. If the values are different, then only differences are sent to the replica peer.

Author:

Maxat Pernebayev, Thomas Bocek

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	RSync.RollingChecksum Variation of Adler as used in Rsync.

Constructor Summary

Constructors

Constructor and Description
RSync()

Method Summary

Methods

Modifier and Type	Method and Description
static List<Checksum>	checksums(byte[] value, int blockSize) It returns an array of weak and strong checksums for the value.
static List<Instruction>	instructions(byte[] array, List<Checksum> checksums, int blockSize) It returns the sequence of instructions each of which contains either reference to a block or literal data.
static DataBuffer	reconstruct(byte[] value, List<Instruction> instructions, int blockSize) It reconstructs the copy of responsible peer's value using instructions and the replica's value.

Methods inherited from class java.lang.Object

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

Constructor Detail

RSync

public RSync()

Method Detail

checksums

public static List<Checksum> checksums(byte[] value,
                       int blockSize)

It returns an array of weak and strong checksums for the value.

Parameters:

value - The value

size - The offset size

Returns:

The array of checksums

Throws:

NoSuchAlgorithmException

instructions

public static List<Instruction> instructions(byte[] array,
                             List<Checksum> checksums,
                             int blockSize)

It returns the sequence of instructions each of which contains either reference to a block or literal data.

Parameters:

array - The value at responsible peer

checksums - The array of checksums

blockSize - The block size

Returns:

The sequence of instructions

reconstruct

public static DataBuffer reconstruct(byte[] value,
                     List<Instruction> instructions,
                     int blockSize)

It reconstructs the copy of responsible peer's value using instructions and the replica's value.

Parameters:

value - The value at replica

instructions - The sequence of instructions

blockSize - The offset size

Returns:

The value which is identical to the responsible peer's value