Package org.bitcoinj.store

Class SPVBlockStore

java.lang.Object

org.bitcoinj.store.SPVBlockStore

All Implemented Interfaces:

BlockStore

public class SPVBlockStore
extends Object
implements BlockStore

An SPVBlockStore holds a limited number of block headers in a memory mapped ring buffer. With such a store, you may not be able to process very deep re-orgs and could be disconnected from the chain (requiring a replay), but as they are virtually unheard of this is not a significant risk.

Field Summary

Fields

Modifier and Type	Field	Description
protected LinkedHashMap<Sha256Hash,StoredBlock>	blockCache
protected MappedByteBuffer	buffer
static final int	DEFAULT_CAPACITY	The default number of headers that will be stored in the ring buffer.
protected static final int	FILE_PROLOGUE_BYTES
protected FileLock	fileLock
static final String	HEADER_MAGIC
protected StoredBlock	lastChainHead
protected final ReentrantLock	lock
protected LinkedHashMap<Sha256Hash,Object>	notFoundCache
protected final NetworkParameters	params
protected RandomAccessFile	randomAccessFile
protected static final int	RECORD_SIZE

Constructor Summary

Constructors

Constructor	Description
SPVBlockStore(NetworkParameters params, File file)	Creates and initializes an SPV block store that can hold DEFAULT_CAPACITY block headers.
SPVBlockStore(NetworkParameters params, File file, int capacity, boolean grow)	Creates and initializes an SPV block store that can hold a given amount of blocks.

Method Summary

Modifier and Type	Method	Description
void	clear()
void	close()	Closes the store.
StoredBlock	get(Sha256Hash hash)	Returns the StoredBlock given a hash.
StoredBlock	getChainHead()	Returns the StoredBlock that represents the top of the chain of greatest total work.
static final int	getFileSize(int capacity)	Returns the size in bytes of the file that is used to store the chain with the current parameters.
NetworkParameters	getParams()	Get the NetworkParameters of this store.
void	put(StoredBlock block)	Saves the given block header+extra data.
void	setChainHead(StoredBlock chainHead)	Sets the StoredBlock that represents the top of the chain of greatest total work.

Methods inherited from class java.lang.Object

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

Field Details

lock

protected final ReentrantLock lock

DEFAULT_CAPACITY

public static final int DEFAULT_CAPACITY

The default number of headers that will be stored in the ring buffer.

See Also:

• Constant Field Values

HEADER_MAGIC

public static final String HEADER_MAGIC

See Also:

• Constant Field Values

buffer

protected volatile MappedByteBuffer buffer

params

protected final NetworkParameters params

blockCache

protected LinkedHashMap<Sha256Hash,StoredBlock> blockCache

notFoundCache

protected LinkedHashMap<Sha256Hash,Object> notFoundCache

fileLock

protected FileLock fileLock

randomAccessFile

protected RandomAccessFile randomAccessFile

lastChainHead

protected StoredBlock lastChainHead

RECORD_SIZE

protected static final int RECORD_SIZE

See Also:

• Constant Field Values

FILE_PROLOGUE_BYTES

protected static final int FILE_PROLOGUE_BYTES

See Also:

• Constant Field Values

Constructor Details

SPVBlockStore

public SPVBlockStore(NetworkParameters params,
 File file)
              throws BlockStoreException

Creates and initializes an SPV block store that can hold DEFAULT_CAPACITY block headers. Will create the given file if it's missing. This operation will block on disk.

Parameters:

file - file to use for the block store

Throws:

BlockStoreException - if something goes wrong

SPVBlockStore

public SPVBlockStore(NetworkParameters params,
 File file,
 int capacity,
 boolean grow)
              throws BlockStoreException

Creates and initializes an SPV block store that can hold a given amount of blocks. Will create the given file if it's missing. This operation will block on disk.

Parameters:

file - file to use for the block store

capacity - custom capacity in number of block headers

grow - wether or not to migrate an existing block store of different capacity

Throws:

BlockStoreException - if something goes wrong

Method Details

getFileSize

public static final int getFileSize(int capacity)

Returns the size in bytes of the file that is used to store the chain with the current parameters.

put

public void put(StoredBlock block)
         throws BlockStoreException

Description copied from interface: BlockStore

Saves the given block header+extra data. The key isn't specified explicitly as it can be calculated from the StoredBlock directly. Can throw if there is a problem with the underlying storage layer such as running out of disk space.

Specified by:

put in interface BlockStore

Throws:

BlockStoreException

get

@Nullable
public StoredBlock get(Sha256Hash hash)
                throws BlockStoreException

Description copied from interface: BlockStore

Returns the StoredBlock given a hash. The returned values block.getHash() method will be equal to the parameter. If no such block is found, returns null.

Specified by:

get in interface BlockStore

Throws:

BlockStoreException

getChainHead

public StoredBlock getChainHead()
                         throws BlockStoreException

Description copied from interface: BlockStore

Returns the StoredBlock that represents the top of the chain of greatest total work. Note that this can be arbitrarily expensive, you probably should use AbstractBlockChain.getChainHead() or perhaps AbstractBlockChain.getBestChainHeight() which will run in constant time and not take any heavyweight locks.

Specified by:

getChainHead in interface BlockStore

Throws:

BlockStoreException

setChainHead

public void setChainHead(StoredBlock chainHead)
                  throws BlockStoreException

Description copied from interface: BlockStore

Sets the StoredBlock that represents the top of the chain of greatest total work.

Specified by:

setChainHead in interface BlockStore

Throws:

BlockStoreException

close

public void close()
           throws BlockStoreException

Description copied from interface: BlockStore

Closes the store.

Specified by:

close in interface BlockStore

Throws:

BlockStoreException

getParams

public NetworkParameters getParams()

Description copied from interface: BlockStore

Get the NetworkParameters of this store.

Specified by:

getParams in interface BlockStore

Returns:

The network params.

clear

public void clear()
           throws Exception

Throws:

Exception