# Package org.h2.mvstore

A persistent storage for tree maps.

See: Description

Interface Summary
MVMap.MapBuilder<M extends MVMap<K,V>,K,V>: A builder for maps.
MVStore.Cleaner: Callback interface to perform cleanup after some unused store versions were dropped.

Class Summary
Chunk: A chunk of data, containing one or multiple pages.
Chunk.PositionComparator
Cursor<K,V>: A cursor to iterate over elements in ascending or descending order.
CursorPos<K,V>: A position in a cursor.
DataUtils: Utility methods
FileStore: The default storage mechanism of the MVStore.
FreeSpaceBitSet: A free space bit set.
MVMap<K,V>: A stored map.
MVMap.BasicBuilder<M extends MVMap<K,V>,K,V>: A builder for this class.
MVMap.Builder<K,V>: A builder for this class.
MVMap.DecisionMaker<V>: Class DecisionMaker provides callback interface (and should become a such in Java 8) for MVMap.operate method.
MVStore: A persistent storage for maps.
MVStore.Builder: A builder for an MVStore.
MVStore.TxCounter: Class TxCounter is a simple data structure to hold version of the store along with the counter of open transactions, which are still operating on this version.
MVStoreTool: Utility methods used in combination with the MVStore.
OffHeapStore: A storage mechanism that "persists" data in the off-heap area of the main memory.
Page<K,V>: A page (a node or a leaf).
Page.PageReference<K,V>: A pointer to a page, either in-memory or using a page position.
RootReference<K,V>: Class RootReference is an immutable structure to represent state of the MVMap as a whole (not related to a particular B-Tree node).
StreamStore: A facility to store streams in a map.
WriteBuffer: An auto-resize buffer to write data into a ByteBuffer.

Enum Summary
MVMap.Decision: The decision on what to do on an update.

Exception Summary
MVStoreException: Various kinds of MVStore problems, along with associated error code.

## Package org.h2.mvstore Description

A persistent storage for tree maps.