org.apache.storm.state

Class BaseStateIterator<K,V,KENCODED,VENCODED>

java.lang.Object

org.apache.storm.state.BaseStateIterator<K,V,KENCODED,VENCODED>

All Implemented Interfaces:

Iterator<Map.Entry<K,V>>

Direct Known Subclasses:

BaseBinaryStateIterator

public abstract class BaseStateIterator<K,V,KENCODED,VENCODED>
extends Object
implements Iterator<Map.Entry<K,V>>

Base implementation of iterator over KeyValueState. Encoded/Decoded types of key and value are all generic.

Constructor Summary

Constructors

Constructor and Description
BaseStateIterator(Iterator<Map.Entry<KENCODED,VENCODED>> pendingPrepareIterator, Iterator<Map.Entry<KENCODED,VENCODED>> pendingCommitIterator, Set<KENCODED> initialProvidedKeys) Constructor.

Method Summary

Modifier and Type	Method and Description
protected abstract K	decodeKey(KENCODED key) Decode key to convert encoded type of key to state key type.
protected abstract V	decodeValue(VENCODED value) Decode value to convert encoded type of value to state value type.
boolean	hasNext()
protected abstract boolean	isEndOfDataFromStorage() Check whether end of data is reached from storage state KVs.
protected abstract boolean	isTombstoneValue(VENCODED value) Check whether the value is tombstone (deletion mark) value.
protected abstract Iterator<Map.Entry<KENCODED,VENCODED>>	loadChunkFromStateStorage() Load some part of state KVs from storage and returns iterator of cached data from storage.
Map.Entry<K,V>	next()
void	remove()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Detail

BaseStateIterator

public BaseStateIterator(Iterator<Map.Entry<KENCODED,VENCODED>> pendingPrepareIterator,
                         Iterator<Map.Entry<KENCODED,VENCODED>> pendingCommitIterator,
                         Set<KENCODED> initialProvidedKeys)

Constructor.

Parameters:

pendingPrepareIterator - The iterator of pendingPrepare

pendingCommitIterator - The iterator of pendingCommit

initialProvidedKeys - The initial value of provided keys

Method Detail

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<Map.Entry<K,V>>

next

public Map.Entry<K,V> next()

Specified by:

next in interface Iterator<Map.Entry<K,V>>

remove

public void remove()

Specified by:

remove in interface Iterator<Map.Entry<K,V>>

loadChunkFromStateStorage

protected abstract Iterator<Map.Entry<KENCODED,VENCODED>> loadChunkFromStateStorage()

Load some part of state KVs from storage and returns iterator of cached data from storage.

Returns:

Iterator of loaded state KVs

isEndOfDataFromStorage

protected abstract boolean isEndOfDataFromStorage()

Check whether end of data is reached from storage state KVs.

Returns:

whether end of data is reached from storage state KVs

decodeKey

protected abstract K decodeKey(KENCODED key)

Decode key to convert encoded type of key to state key type.

Parameters:

key - raw type of encoded key

Returns:

Decoded value of key

decodeValue

protected abstract V decodeValue(VENCODED value)

Decode value to convert encoded type of value to state value type.

Parameters:

value - raw type of encoded value

Returns:

Decoded value of value

isTombstoneValue

protected abstract boolean isTombstoneValue(VENCODED value)

Check whether the value is tombstone (deletion mark) value.

Parameters:

value - the value to check

Returns:

true if the value is tombstone, false otherwise