/*
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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 java.io.Closeable;
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import java.util.NoSuchElementException;
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/**
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* 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 SequentialCursor<K,V> extends Closeable
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{
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/**
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* Moves this cursor to the next record in the tree.
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*
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* @return {@code true} if the cursor has moved to the next record,
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* {@code false} if no next record exists leaving cursor
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* in undefined state.
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*/
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boolean next();
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/**
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* Check whether this cursor is currently pointing to valid record.
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*
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* @return {@code true} if the cursor is pointing to a valid entry,
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* {@code false} if cursor is not pointing to a valid entry
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*/
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boolean isDefined();
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/**
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* Returns the key of the record on which this cursor is currently positioned.
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*
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* @return the current record's key.
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* @throws NoSuchElementException if the cursor is not defined.
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*/
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K getKey() throws NoSuchElementException;
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/**
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* Returns the value of the record on which this cursor is currently positioned.
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*
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* @return the current record's value.
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* @throws NoSuchElementException if the cursor is not defined.
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*/
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V getValue() throws NoSuchElementException;
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/**
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* Deletes the record on which this cursor is currently positioned. This method does not alter the position of the
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* cursor. In particular, {@link #next()} must be called in order to point to the next record. The behavior of
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* methods {@link #getKey()} and {@link #getValue()} after this method returns is undefined.
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*
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* @throws NoSuchElementException if the cursor is not defined.
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* @throws UnsupportedOperationException if the cursor implementation does not support updates.
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*/
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void delete() throws NoSuchElementException, UnsupportedOperationException;
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/** {@inheritDoc} */
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@Override
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void close();
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}
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