001/*
002 * The contents of this file are subject to the terms of the Common Development and
003 * Distribution License (the License). You may not use this file except in compliance with the
004 * License.
005 *
006 * You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
007 * specific language governing permission and limitations under the License.
008 *
009 * When distributing Covered Software, include this CDDL Header Notice in each file and include
010 * the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
011 * Header, with the fields enclosed by brackets [] replaced by your own identifying
012 * information: "Portions Copyright [year] [name of copyright owner]".
013 *
014 * Copyright 2014-2015 ForgeRock AS.
015 */
016package org.opends.server.backends.pluggable.spi;
017
018import org.forgerock.opendj.ldap.ByteSequence;
019import org.forgerock.opendj.ldap.ByteString;
020
021/**
022 * Represents a readable transaction on a storage engine.
023 */
024public interface ReadableTransaction
025{
026  /**
027   * Reads the record's value associated to the provided key, in the tree whose name is provided.
028   *
029   * @param treeName
030   *          the tree name
031   * @param key
032   *          the record's key
033   * @return the record's value, or {@code null} if none exists
034   */
035  ByteString read(TreeName treeName, ByteSequence key);
036
037  /**
038   * Opens a cursor on the tree whose name is provided.
039   *
040   * @param treeName
041   *          the tree name
042   * @return a new cursor
043   */
044  Cursor<ByteString, ByteString> openCursor(TreeName treeName);
045
046  /**
047   * Returns the number of key/value pairs in the provided tree.
048   *
049   * @param treeName
050   *          the tree name
051   * @return the number of key/value pairs in the provided tree.
052   */
053  long getRecordCount(TreeName treeName);
054}