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