Package org.opends.server.backends.pluggable.spi

Interface Cursor<K,V>

Type Parameters:

K - Type of the record's key

V - Type of the record's value

All Superinterfaces:

AutoCloseable, Closeable, SequentialCursor<K,V>

All Known Implementing Classes:

EmptyCursor

public interface Cursor<K,V>
extends SequentialCursor<K,V>

Sequential cursor extended with navigation methods.

Method Summary

Modifier and Type	Method	Description
default boolean	positionToIndex(int index)	Positions the cursor to the specified index within the tree.
default boolean	positionToKey(K key)	Positions the cursor to the provided key if it exists in the tree.
default boolean	positionToKeyOrNext(K key)	Positions the cursor to the provided key if it exists in the tree, or else the lesser key greater than the provided key in the tree.
default boolean	positionToLastKey()	Positions the cursor to the last key in the tree.
default boolean	previous()	Moves this cursor to the previous record in the tree.

Methods inherited from interface org.opends.server.backends.pluggable.spi.SequentialCursor

close, delete, getKey, getValue, isValid, next

Method Details

previous

default boolean previous()

Moves this cursor to the previous record in the tree.

Returns:

true if the cursor has moved to the previous record, false if no next record exists leaving cursor in undefined state.

positionToKey

default boolean positionToKey(K key)

Positions the cursor to the provided key if it exists in the tree.

Positioning the cursor is required before calling SequentialCursor.isValid().

Parameters:

key - the key where to position the cursor

Returns:

true if the cursor could be positioned to the key, false otherwise

positionToKeyOrNext

default boolean positionToKeyOrNext(K key)

Positions the cursor to the provided key if it exists in the tree, or else the lesser key greater than the provided key in the tree.

Positioning the cursor is required before calling SequentialCursor.isValid().

Parameters:

key - the key where to position the cursor

Returns:

true if the cursor could be positioned to the key or the next one, false otherwise

positionToLastKey

default boolean positionToLastKey()

Positions the cursor to the last key in the tree.

Positioning the cursor is required before calling SequentialCursor.isValid().

Returns:

true if the cursor could be positioned to the last key, false otherwise

positionToIndex

default boolean positionToIndex(int index)

Positions the cursor to the specified index within the tree. Implementations may take advantage of optimizations provided by the underlying storage, such as counted B-Trees.

Positioning the cursor is required before calling SequentialCursor.isValid().

Parameters:

index - the index where the cursor should be positioned, (0 is the first record).

Returns:

true if the cursor could be positioned to the index, false otherwise