Module dev.hloth.zgztransport

Package dev.hloth.zgztransport

Class TransactionLog

java.lang.Object

dev.hloth.zgztransport.TransactionLog

public final class TransactionLog
extends Object

The ring of six blocks a card keeps its last transactions in: block 5 holds the newest record, and the five before it live in the archive blocks, each in the slot its sequence byte picks.

Field Summary

Fields

Modifier and Type	Field	Description
static final List<Integer>	ARCHIVE_BLOCKS	The blocks holding the five records before the newest, indexed by sequence byte.
static final List<Integer>	BLOCKS	The six slots, in the order decode(byte[][]) expects.
static final int	LIVE_BLOCK	The block holding the newest record.

Method Summary

Modifier and Type	Method	Description
static OptionalInt	archiveBlock(int sequence)	The block a record moves to when a newer one replaces it.
static List<Transaction>	decode(byte[][] slots)	Decodes the six slots of the ring, oldest record first.

Methods inherited from class java.lang.Object

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

Field Details

LIVE_BLOCK

public static final int LIVE_BLOCK

The block holding the newest record.

See Also:

• Constant Field Values

ARCHIVE_BLOCKS

public static final List<Integer> ARCHIVE_BLOCKS

The blocks holding the five records before the newest, indexed by sequence byte.

BLOCKS

public static final List<Integer> BLOCKS

The six slots, in the order decode(byte[][]) expects.

Method Details

archiveBlock

public static OptionalInt archiveBlock(int sequence)

The block a record moves to when a newer one replaces it.

Parameters:

sequence - the sequence byte of the record

Returns:

the block number, or empty when the byte is not one the ring uses

decode

public static List<Transaction> decode(byte[][] slots)

Decodes the six slots of the ring, oldest record first. Slots whose first byte is zero hold no record and are skipped; records that share a timestamp keep the order of the slots.

Parameters:

slots - the six blocks, in the order of BLOCKS

Returns:

the records the ring holds

Throws:

CardFormatException - if there are not six slots or an occupied one does not decode