org.apache.flink.runtime.state

Interface KeyValueStateIterator

All Superinterfaces:

AutoCloseable

All Known Implementing Classes:

HeapKeyValueStateIterator, RocksStatesPerKeyGroupMergeIterator

public interface KeyValueStateIterator
extends AutoCloseable

Iterator that over all key-value state entries in a KeyedStateBackend. For use during snapshotting.

This is required to partition all states into contiguous key-groups. The resulting iteration sequence is ordered by (key-group, kv-state).

Method Summary

Modifier and Type	Method and Description
void	close()
boolean	isNewKeyGroup() Indicates if current key starts a new key-group, i.e. belong to a different key-group than it's predecessor.
boolean	isNewKeyValueState() Indicates if current key starts a new k/v-state, i.e. belong to a different k/v-state than it's predecessor.
boolean	isValid() Check if the iterator is still valid.
byte[]	key()
int	keyGroup() Returns the key-group for the current key.
int	kvStateId() Returns the Id of the K/V state to which the current key belongs.
void	next() Advances the iterator.
byte[]	value()

Method Detail

next

void next()
   throws IOException

Advances the iterator. Should only be called if isValid() returned true. Valid flag can only change after calling next().

Throws:

IOException

keyGroup

int keyGroup()

Returns the key-group for the current key.

key

byte[] key()

value

byte[] value()

kvStateId

int kvStateId()

Returns the Id of the K/V state to which the current key belongs.

isNewKeyValueState

boolean isNewKeyValueState()

Indicates if current key starts a new k/v-state, i.e. belong to a different k/v-state than it's predecessor.

Returns:

true iff the current key belong to a different k/v-state than it's predecessor.

isNewKeyGroup

boolean isNewKeyGroup()

Indicates if current key starts a new key-group, i.e. belong to a different key-group than it's predecessor.

Returns:

true iff the current key belong to a different key-group than it's predecessor.

isValid

boolean isValid()

Check if the iterator is still valid. Getters like key(), value(), etc. as well as next() should only be called if valid returned true. Should be checked after each call to next() before accessing iterator state.

Returns:

True iff this iterator is valid.

close

void close()

Specified by:

close in interface AutoCloseable