/*
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* The contents of this file are subject to the terms of the Common Development and
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* Distribution License (the License). You may not use this file except in compliance with the
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* License.
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*
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* You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
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* specific language governing permission and limitations under the License.
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*
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* When distributing Covered Software, include this CDDL Header Notice in each file and include
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* the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
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* Header, with the fields enclosed by brackets [] replaced by your own identifying
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* information: "Portions Copyright [year] [name of copyright owner]".
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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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* or the next one, {@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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