org.bitcoinj.core

Class StoredBlock

java.lang.Object

org.bitcoinj.core.StoredBlock

public class StoredBlock
extends Object

Wraps a Block object with extra data that can be derived from the block chain but is slow or inconvenient to calculate. By storing it alongside the block header we reduce the amount of work required significantly. Recalculation is slow because the fields are cumulative - to find the chainWork you have to iterate over every block in the chain back to the genesis block, which involves lots of seeking/loading etc. So we just keep a running total: it's a disk space vs cpu/io tradeoff.

StoredBlocks are put inside a BlockStore which saves them to memory or disk.

Field Summary

Fields

Modifier and Type	Field and Description
static int	CHAIN_WORK_BYTES
static int	COMPACT_SERIALIZED_SIZE
static byte[]	EMPTY_BYTES

Constructor Summary

Constructors

Constructor and Description
StoredBlock(Block header, BigInteger chainWork, int height)

Method Summary

Modifier and Type	Method and Description
StoredBlock	build(Block block) Creates a new StoredBlock, calculating the additional fields by adding to the values in this block.
static StoredBlock	deserializeCompact(NetworkParameters params, ByteBuffer buffer) De-serializes the stored block from a custom packed format.
boolean	equals(Object o)
BigInteger	getChainWork() The total sum of work done in this block, and all the blocks below it in the chain.
Block	getHeader() The block header this object wraps.
int	getHeight() Position in the chain for this block.
StoredBlock	getPrev(BlockStore store) Given a block store, looks up the previous block in this chain.
int	hashCode()
boolean	moreWorkThan(StoredBlock other) Returns true if this objects chainWork is higher than the others.
void	serializeCompact(ByteBuffer buffer) Serializes the stored block to a custom packed format.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

CHAIN_WORK_BYTES

public static final int CHAIN_WORK_BYTES

See Also:

Constant Field Values

EMPTY_BYTES

public static final byte[] EMPTY_BYTES

COMPACT_SERIALIZED_SIZE

public static final int COMPACT_SERIALIZED_SIZE

See Also:

Constant Field Values

Constructor Detail

StoredBlock

public StoredBlock(Block header,
                   BigInteger chainWork,
                   int height)

Method Detail

getHeader

public Block getHeader()

The block header this object wraps. The referenced block object must not have any transactions in it.

getChainWork

public BigInteger getChainWork()

The total sum of work done in this block, and all the blocks below it in the chain. Work is a measure of how many tries are needed to solve a block. If the target is set to cover 10% of the total hash value space, then the work represented by a block is 10.

getHeight

public int getHeight()

Position in the chain for this block. The genesis block has a height of zero.

moreWorkThan

public boolean moreWorkThan(StoredBlock other)

Returns true if this objects chainWork is higher than the others.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

build

public StoredBlock build(Block block)
                  throws VerificationException

Creates a new StoredBlock, calculating the additional fields by adding to the values in this block.

Throws:

VerificationException

getPrev

public StoredBlock getPrev(BlockStore store)
                    throws BlockStoreException

Given a block store, looks up the previous block in this chain. Convenience method for doing store.get(this.getHeader().getPrevBlockHash()).

Returns:

the previous block in the chain or null if it was not found in the store.

Throws:

BlockStoreException

serializeCompact

public void serializeCompact(ByteBuffer buffer)

Serializes the stored block to a custom packed format. Used by CheckpointManager.

deserializeCompact

public static StoredBlock deserializeCompact(NetworkParameters params,
                                             ByteBuffer buffer)
                                      throws ProtocolException

De-serializes the stored block from a custom packed format. Used by CheckpointManager.

Throws:

ProtocolException

toString

public String toString()

Overrides:

toString in class Object