/*
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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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*
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* Copyright 2006-2010 Sun Microsystems, Inc.
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* Portions Copyright 2012-2016 ForgeRock AS.
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*/
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package org.opends.server.replication.plugin;
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import java.util.Collections;
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import java.util.LinkedList;
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import java.util.List;
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import org.forgerock.i18n.slf4j.LocalizedLogger;
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import org.forgerock.opendj.ldap.ByteString;
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import org.forgerock.opendj.ldap.ModificationType;
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import org.forgerock.opendj.ldap.ResultCode;
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import org.forgerock.opendj.ldap.SearchScope;
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import org.forgerock.opendj.ldap.schema.AttributeType;
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import org.opends.server.core.DirectoryServer;
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import org.opends.server.core.ModifyOperationBasis;
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import org.opends.server.protocols.internal.InternalSearchOperation;
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import org.opends.server.protocols.internal.SearchRequest;
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import org.opends.server.protocols.ldap.LDAPAttribute;
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import org.opends.server.protocols.ldap.LDAPModification;
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import org.opends.server.replication.common.CSN;
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import org.opends.server.replication.common.ServerState;
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import org.opends.server.types.Attribute;
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import org.opends.server.types.DN;
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import org.opends.server.types.DirectoryException;
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import org.opends.server.types.RawModification;
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import org.opends.server.types.SearchResultEntry;
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import static org.opends.messages.ReplicationMessages.*;
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import static org.opends.server.protocols.internal.InternalClientConnection.*;
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import static org.opends.server.protocols.internal.Requests.*;
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/**
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* This class implements a ServerState that is stored in the backend
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* used to store the synchronized data and that is therefore persistent
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* across server reboot.
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*/
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class PersistentServerState
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{
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private static final LocalizedLogger logger = LocalizedLogger.getLoggerForThisClass();
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private final DN baseDN;
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private final int serverId;
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private final ServerState state;
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/**
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* The attribute name used to store the state in the backend.
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*/
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private static final String REPLICATION_STATE = "ds-sync-state";
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/**
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* Create a new PersistentServerState based on an already existing
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* ServerState.
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*
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* @param baseDN The baseDN for which the ServerState is created.
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* @param serverId The serverId.
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* @param state The serverState.
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*/
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PersistentServerState(DN baseDN, int serverId, ServerState state)
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{
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this.baseDN = baseDN;
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this.serverId = serverId;
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this.state = state;
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loadState();
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}
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/**
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* Checks that the CSN given as a parameter is in this ServerState.
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*
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* @param covered The CSN that should be checked.
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* @return A boolean indicating if this ServerState contains the CSN
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* given in parameter.
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*/
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boolean cover(CSN covered)
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{
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return state.cover(covered);
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}
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/**
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* Update the Server State with a CSN. All operations with smaller CSN and the
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* same serverID must be committed before calling this method.
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*
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* @param csn
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* The committed CSN.
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* @return a boolean indicating if the update was meaningful.
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*/
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boolean update(CSN csn)
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{
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return state.update(csn);
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}
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/**
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* Save this object to persistent storage.
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*/
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public void save()
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{
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if (!state.isSaved())
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{
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state.setSaved(updateStateEntry());
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}
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}
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/**
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* Load the ServerState from the backing entry in database to memory.
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*/
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public void loadState()
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{
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// try to load the state from the base entry.
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SearchResultEntry stateEntry = searchBaseEntry();
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if (stateEntry == null)
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{
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/*
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The base entry does not exist yet in the database or was deleted.
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Try to read the ServerState from the configuration instead.
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*/
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stateEntry = searchConfigEntry();
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}
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if (stateEntry != null)
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{
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updateStateFromEntry(stateEntry);
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}
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/*
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* In order to make sure that the replication never looses changes,
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* the server needs to search all the entries that have been
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* updated after the last write of the ServerState.
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* Inconsistencies may append after a crash.
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*/
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checkAndUpdateServerState();
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}
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/**
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* Run a search operation to find the base entry
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* of the replication domain for which this ServerState was created.
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*
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* @return The base entry or null if no entry was found;
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*/
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private SearchResultEntry searchBaseEntry()
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{
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// Search the database entry that is used to periodically save the ServerState
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final SearchRequest request = newSearchRequest(baseDN, SearchScope.BASE_OBJECT).addAttribute(REPLICATION_STATE);
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final InternalSearchOperation search = getRootConnection().processSearch(request);
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final ResultCode resultCode = search.getResultCode();
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if (resultCode != ResultCode.SUCCESS
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&& resultCode != ResultCode.NO_SUCH_OBJECT)
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{
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logger.error(ERR_ERROR_SEARCHING_RUV, search.getResultCode().getName(), search, search.getErrorMessage(), baseDN);
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return null;
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}
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return getFirstResult(search);
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}
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/**
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* Run a search operation to find the entry with the configuration
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* of the replication domain for which this ServerState was created.
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*
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* @return The configuration Entry or null if no entry was found;
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*/
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private SearchResultEntry searchConfigEntry()
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{
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try
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{
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String filter = "(&(objectclass=ds-cfg-replication-domain)" + "(ds-cfg-base-dn=" + baseDN + "))";
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final SearchRequest request = newSearchRequest("cn=config", SearchScope.SUBORDINATES, filter)
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.setSizeLimit(1)
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.addAttribute(REPLICATION_STATE);
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final InternalSearchOperation op = getRootConnection().processSearch(request);
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return getFirstResult(op);
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}
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catch (DirectoryException e)
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{
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// can not happen
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return null;
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}
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}
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private SearchResultEntry getFirstResult(InternalSearchOperation search)
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{
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if (search.getResultCode() == ResultCode.SUCCESS)
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{
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final LinkedList<SearchResultEntry> results = search.getSearchEntries();
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if (!results.isEmpty())
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{
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return results.getFirst();
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}
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}
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return null;
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}
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/**
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* Update this ServerState from the provided entry.
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*
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* @param resultEntry
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* The entry that should be used to update this ServerState.
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*/
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private void updateStateFromEntry(SearchResultEntry resultEntry)
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{
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AttributeType synchronizationStateType = DirectoryServer.getAttributeTypeOrNull(REPLICATION_STATE);
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List<Attribute> attrs = resultEntry.getAttribute(synchronizationStateType);
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if (!attrs.isEmpty())
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{
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for (ByteString value : attrs.get(0))
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{
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update(new CSN(value.toString()));
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}
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}
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}
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/**
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* Save the current values of this PersistentState object
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* in the appropriate entry of the database.
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*
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* @return a boolean indicating if the method was successful.
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*/
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private boolean updateStateEntry()
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{
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// Generate a modify operation on the Server State baseDN Entry.
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ResultCode result = runUpdateStateEntry(baseDN);
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if (result == ResultCode.NO_SUCH_OBJECT)
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{
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// The base entry does not exist yet in the database or has been deleted,
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// save the state to the config entry instead.
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SearchResultEntry configEntry = searchConfigEntry();
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if (configEntry != null)
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{
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result = runUpdateStateEntry(configEntry.getName());
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}
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}
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return result == ResultCode.SUCCESS;
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}
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/**
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* Run a modify operation to update the entry whose DN is given as
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* a parameter with the serverState information.
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*
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* @param serverStateEntryDN The DN of the entry to be updated.
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*
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* @return A ResultCode indicating if the operation was successful.
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*/
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private ResultCode runUpdateStateEntry(DN serverStateEntryDN)
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{
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LDAPAttribute attr = new LDAPAttribute(REPLICATION_STATE, state.toASN1ArrayList());
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RawModification mod = new LDAPModification(ModificationType.REPLACE, attr);
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ModifyOperationBasis op = new ModifyOperationBasis(getRootConnection(),
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nextOperationID(), nextMessageID(), null,
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ByteString.valueOfUtf8(serverStateEntryDN.toString()),
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Collections.singletonList(mod));
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op.setInternalOperation(true);
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op.setSynchronizationOperation(true);
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op.setDontSynchronize(true);
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op.run();
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if (op.getResultCode() != ResultCode.SUCCESS)
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{
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logger.error(DEBUG_ERROR_UPDATING_RUV,
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op.getResultCode().getName(), op, op.getErrorMessage(), baseDN);
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}
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return op.getResultCode();
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}
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/**
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* Empty the ServerState.
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* After this call the Server State will be in the same state
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* as if it was just created.
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*/
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public void clearInMemory()
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{
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state.clear();
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state.setSaved(false);
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}
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/**
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* Empty the ServerState.
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* After this call the Server State will be in the same state
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* as if it was just created.
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*/
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void clear()
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{
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clearInMemory();
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save();
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}
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/**
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* The ServerState is saved to the database periodically,
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* therefore in case of crash it is possible that is does not contain
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* the latest changes that have been processed and saved to the
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* database.
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* In order to make sure that we don't loose them, search all the entries
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* that have been updated after this entry.
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* This is done by using the HistoricalCsnOrderingMatchingRule
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* and an ordering index for historical attribute
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*/
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private final void checkAndUpdateServerState()
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{
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final AttributeType histType = DirectoryServer.getAttributeTypeOrNull(EntryHistorical.HISTORICAL_ATTRIBUTE_NAME);
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// Retrieves the entries that have changed since the
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// maxCsn stored in the serverState
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synchronized (this)
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{
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CSN serverStateMaxCSN = state.getCSN(serverId);
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if (serverStateMaxCSN == null)
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{
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return;
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}
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InternalSearchOperation op;
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try
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{
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op = LDAPReplicationDomain.searchForChangedEntries(baseDN,
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serverStateMaxCSN, null);
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}
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catch (Exception e)
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{
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return;
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}
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if (op.getResultCode() != ResultCode.SUCCESS)
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{
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// An error happened trying to search for the updates
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// Log an error
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logger.error(ERR_CANNOT_RECOVER_CHANGES, baseDN);
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return;
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}
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CSN dbMaxCSN = serverStateMaxCSN;
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for (SearchResultEntry resEntry : op.getSearchEntries())
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{
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for (ByteString attrValue : resEntry.getAttribute(histType).get(0))
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{
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HistoricalAttributeValue histVal =
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new HistoricalAttributeValue(attrValue.toString());
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CSN csn = histVal.getCSN();
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if (csn != null
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&& csn.getServerId() == serverId
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&& dbMaxCSN.isOlderThan(csn))
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{
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dbMaxCSN = csn;
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}
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}
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}
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if (dbMaxCSN.isNewerThan(serverStateMaxCSN))
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{
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// Update the serverState with the new maxCsn present in the database
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update(dbMaxCSN);
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logger.info(NOTE_SERVER_STATE_RECOVERY, baseDN, dbMaxCSN);
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}
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}
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}
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/**
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* Get the largest CSN seen for a given LDAP server ID.
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*
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* @param serverId
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* The serverId
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* @return The largest CSN seen
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*/
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public CSN getMaxCSN(int serverId)
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{
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return state.getCSN(serverId);
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}
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/** {@inheritDoc} */
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@Override
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public String toString()
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{
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return getClass().getSimpleName()
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+ " baseDN=" + baseDN
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+ " serverId=" + serverId
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+ " " + REPLICATION_STATE + "=" + state;
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}
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}
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