/*
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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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* Copyright 2014 ForgeRock AS
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*/
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package org.opends.server.backends.pluggable;
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import java.io.Closeable;
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import org.opends.server.types.DirectoryException;
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/**
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* Interface for a key-value store, also known as an index.
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*
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* @param <K>
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* type of key objects
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* @param <V>
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* type of value objects
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* @param <T>
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* type of transaction objects. Underlying databases that do not
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* support transactions should use a {@link Void} type parameter and
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* pass in a null value.
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* @param <M>
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* type of lock mode objects. Underlying databases might not need this
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* parameter. They should use a {@link Void} type parameter and pass in
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* a null value.
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*/
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public interface KeyValueStore<K, V, T, M> extends Closeable
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{
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/**
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* Opens a key-value store.
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*
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* @throws DirectoryException
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* If an error occurs while opening the key-value store.
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*/
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void open() throws DirectoryException;
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/**
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* Inserts a new record for the provided key-value mapping in the key-value
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* store.
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*
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* @param txn
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* the current transaction
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* @param key
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* the key to use when inserting the provided value
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* @param value
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* the value to insert
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* @return true if the record was inserted, false if a record with that key
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* already exists.
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* @throws DirectoryException
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* If an error occurs while opening the key-value store.
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*/
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boolean insert(T txn, K key, V value) throws DirectoryException;
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/**
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* Puts the provided key-value mapping in the key-value store, overwriting any
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* previous mapping for the key.
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*
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* @param txn
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* the current transaction
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* @param key
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* the key to use when putting the provided value
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* @param value
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* the value to put
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* @return true if the key-value mapping could be put in the key-value store,
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* false otherwise
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* @throws DirectoryException
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* If an error occurs while opening the key-value store.
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*/
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boolean put(T txn, K key, V value) throws DirectoryException;
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/**
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* Returns the value associated to the provided key.
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*
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* @param txn
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* the current transaction
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* @param key
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* the key for which to retrieve the value
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* @param mode
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* the mode to use when retrieving the value
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* @return The value associated with the provided key, or null if there is no
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* such key-value mapping
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* @throws DirectoryException
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* If an error occurs while opening the key-value store.
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*/
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V get(T txn, K key, M mode) throws DirectoryException;
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/**
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* Removes the mapping for the provided key in the key-value store.
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*
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* @param txn
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* the current transaction
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* @param key
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* the key to remove from the key-value store
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* @return true if the key could be removed, false otherwise
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* @throws DirectoryException
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* If an error occurs while opening the key-value store.
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*/
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boolean remove(T txn, K key) throws DirectoryException;
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}
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