/*
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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.replication.server.changelog.je;
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import org.opends.server.replication.common.CSN;
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import org.opends.server.replication.protocol.ReplicaOfflineMsg;
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import org.opends.server.replication.protocol.UpdateMsg;
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import org.opends.server.replication.server.changelog.api.ChangelogException;
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import org.opends.server.replication.server.changelog.api.DBCursor;
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/**
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* Implementation of a DBCursor that decorates an existing DBCursor
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* and returns a ReplicaOfflineMsg when the decorated DBCursor is exhausted
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* and the offline CSN is newer than the last returned update CSN.
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*/
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public class ReplicaOfflineCursor implements DBCursor<UpdateMsg>
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{
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/** @NonNull */
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private final DBCursor<UpdateMsg> cursor;
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private ReplicaOfflineMsg replicaOfflineMsg;
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/**
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* Whether calls to {@link #getRecord()} must return the {@link ReplicaOfflineMsg}
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*/
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private boolean returnReplicaOfflineMsg;
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/**
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* Creates a ReplicaOfflineCursor object with a cursor to decorate
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* and an offlineCSN to return as part of a ReplicaOfflineMsg.
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*
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* @param cursor
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* the non-null underlying cursor that needs to be exhausted before
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* we return a ReplicaOfflineMsg
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* @param offlineCSN
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* The offline CSN from which to builder the
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* {@link ReplicaOfflineMsg} to return
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*/
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public ReplicaOfflineCursor(DBCursor<UpdateMsg> cursor, CSN offlineCSN)
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{
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this.replicaOfflineMsg =
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offlineCSN != null ? new ReplicaOfflineMsg(offlineCSN) : null;
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this.cursor = cursor;
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}
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/** {@inheritDoc} */
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@Override
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public UpdateMsg getRecord()
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{
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return returnReplicaOfflineMsg ? replicaOfflineMsg : cursor.getRecord();
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}
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/** {@inheritDoc} */
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@Override
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public boolean next() throws ChangelogException
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{
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if (returnReplicaOfflineMsg)
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{
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// already consumed, never return it again...
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replicaOfflineMsg = null;
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returnReplicaOfflineMsg = false;
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// ...and verify if new changes have been added to the DB
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// (cursors are automatically restarted)
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}
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final UpdateMsg lastUpdate = cursor.getRecord();
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final boolean hasNext = cursor.next();
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if (hasNext)
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{
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return true;
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}
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if (replicaOfflineMsg == null)
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{ // no ReplicaOfflineMsg to return
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return false;
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}
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// replicaDB just happened to be exhausted now
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if (lastUpdate != null
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&& replicaOfflineMsg.getCSN().isOlderThanOrEqualTo(lastUpdate.getCSN()))
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{
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// offlineCSN is outdated, never return it
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replicaOfflineMsg = null;
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return false;
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}
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returnReplicaOfflineMsg = true;
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return true;
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}
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/** {@inheritDoc} */
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@Override
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public void close()
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{
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cursor.close();
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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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+ " returnReplicaOfflineMsg=" + returnReplicaOfflineMsg
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+ " offlineCSN="
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+ (replicaOfflineMsg != null ? replicaOfflineMsg.getCSN().toStringUI() : null)
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+ " cursor=" + cursor.toString().split("", 2)[1];
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}
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}
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