/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
* or http://forgerock.org/license/CDDLv1.0.html.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at legal-notices/CDDLv1_0.txt.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information:
* Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*
*
* Copyright 2014-2015 ForgeRock AS
*/
package org.opends.server.backends.pluggable.spi;
import org.forgerock.opendj.ldap.ByteSequence;
/**
* Sequential cursor extended with navigation methods.
* @param <K> Type of the record's key
* @param <V> Type of the record's value
*/
public interface Cursor<K,V> extends SequentialCursor<K, V>
{
/**
* Positions the cursor to the provided key if it exists in the tree.
*
* @param key
* the key where to position the cursor
* @return {@code true} if the cursor could be positioned to the key,
* {@code false} otherwise
*/
boolean positionToKey(ByteSequence 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.
*
* @param key
* the key where to position the cursor
* @return {@code true} if the cursor could be positioned to the key
* or the next one, {@code false} otherwise
*/
boolean positionToKeyOrNext(ByteSequence key);
/**
* Positions the cursor to the last key in the tree.
*
* @return {@code true} if the cursor could be positioned to the last key,
* {@code false} otherwise
*/
boolean positionToLastKey();
/**
* 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.
*
* @param index
* the index where the cursor should be positioned, (0 is the first record).
* @return {@code true} if the cursor could be positioned to the index, {@code false} otherwise
*/
boolean positionToIndex(int index);
}