001/*
002 * CDDL HEADER START
003 *
004 * The contents of this file are subject to the terms of the
005 * Common Development and Distribution License, Version 1.0 only
006 * (the "License").  You may not use this file except in compliance
007 * with the License.
008 *
009 * You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
010 * or http://forgerock.org/license/CDDLv1.0.html.
011 * See the License for the specific language governing permissions
012 * and limitations under the License.
013 *
014 * When distributing Covered Code, include this CDDL HEADER in each
015 * file and include the License file at legal-notices/CDDLv1_0.txt.
016 * If applicable, add the following below this CDDL HEADER, with the
017 * fields enclosed by brackets "[]" replaced with your own identifying
018 * information:
019 *      Portions Copyright [yyyy] [name of copyright owner]
020 *
021 * CDDL HEADER END
022 *
023 *
024 *      Copyright 2014-2015 ForgeRock AS
025 */
026package org.opends.server.backends.pluggable.spi;
027
028import org.forgerock.opendj.ldap.ByteSequence;
029import org.forgerock.opendj.ldap.ByteString;
030
031/**
032 * Represents a readable transaction on a storage engine.
033 */
034public interface ReadableTransaction
035{
036  /**
037   * Reads the record's value associated to the provided key, in the tree whose name is provided.
038   *
039   * @param treeName
040   *          the tree name
041   * @param key
042   *          the record's key
043   * @return the record's value, or {@code null} if none exists
044   */
045  ByteString read(TreeName treeName, ByteSequence key);
046
047  /**
048   * Opens a cursor on the tree whose name is provided.
049   *
050   * @param treeName
051   *          the tree name
052   * @return a new cursor
053   */
054  Cursor<ByteString, ByteString> openCursor(TreeName treeName);
055
056  /**
057   * Returns the number of key/value pairs in the provided tree.
058   *
059   * @param treeName
060   *          the tree name
061   * @return the number of key/value pairs in the provided tree.
062   */
063  long getRecordCount(TreeName treeName);
064}