org.hyperledger.fabric.gateway.spi

Interface Checkpointer

All Superinterfaces:

AutoCloseable

public interface Checkpointer
extends AutoCloseable

Persists the current block and transactions within that block to enable event listening to be resumed following an application outage.

Default implementations can be obtained from DefaultCheckpointers. Application developers are encouraged to build their own implementations that use a persistent store suitable to their environment.

Implementations must be thread-safe.

Field Summary

Fields

Modifier and Type	Field and Description
static long	UNSET_BLOCK_NUMBER Block number indicating no stored value.

Method Summary

Modifier and Type	Method and Description
void	addTransactionId(String transactionId) Add a transaction ID for the current block.
void	close()
long	getBlockNumber() Get the current block number, or UNSET_BLOCK_NUMBER if there is no previously saved state.
Set<String>	getTransactionIds() Get the transaction IDs processed within the current block.
void	setBlockNumber(long blockNumber) Set the current block number.

Field Detail

UNSET_BLOCK_NUMBER

static final long UNSET_BLOCK_NUMBER

Block number indicating no stored value. This is the the default for a newly created checkpointer with no previously saved state.

See Also:

Constant Field Values

Method Detail

getBlockNumber

long getBlockNumber()
             throws IOException

Get the current block number, or UNSET_BLOCK_NUMBER if there is no previously saved state.

Returns:

A block number.

Throws:

IOException - if the checkpointer fails to access persistent state.

setBlockNumber

void setBlockNumber(long blockNumber)
             throws IOException

Set the current block number. Also clears the stored transaction IDs. Typically set when the previous block has been processed.

Parameters:

blockNumber - A block number.

Throws:

IOException - if the checkpointer fails to access persistent state.

getTransactionIds

Set<String> getTransactionIds()
                       throws IOException

Get the transaction IDs processed within the current block.

Returns:

Transaction IDs.

Throws:

IOException - if the checkpointer fails to access persistent state.

addTransactionId

void addTransactionId(String transactionId)
               throws IOException

Add a transaction ID for the current block. Typically called once a transaction has been processed.

Parameters:

transactionId - A transaction ID.

Throws:

IOException - if the checkpointer fails to access persistent state.

close

void close()
    throws IOException

Specified by:

close in interface AutoCloseable

Throws:

IOException