/*
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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
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE
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* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
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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
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
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* add the following below this CDDL HEADER, with the fields enclosed
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* by brackets "[]" replaced with your own identifying 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 2006-2009 Sun Microsystems, Inc.
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*/
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package org.opends.server.replication.server;
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import org.opends.messages.MessageBuilder;
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import static org.opends.server.loggers.ErrorLogger.logError;
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import static org.opends.messages.ReplicationMessages.*;
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import static org.opends.server.util.StaticUtils.stackTraceToSingleLineString;
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import java.util.List;
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import java.io.UnsupportedEncodingException;
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import org.opends.server.replication.common.ChangeNumber;
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import org.opends.server.replication.protocol.UpdateMsg;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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import com.sleepycat.je.Cursor;
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import com.sleepycat.je.DatabaseEntry;
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import com.sleepycat.je.DatabaseException;
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import com.sleepycat.je.Database;
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import com.sleepycat.je.LockConflictException;
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import com.sleepycat.je.LockMode;
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import com.sleepycat.je.OperationStatus;
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import com.sleepycat.je.Transaction;
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/**
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* This class implements the interface between the underlying database
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* and the dbHandler class.
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* This is the only class that should have code using the BDB interfaces.
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*/
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public class ReplicationDB
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{
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private Database db = null;
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private ReplicationDbEnv dbenv = null;
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private ReplicationServer replicationServer;
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private int serverId;
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private String baseDn;
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// The maximum number of retries in case of DatabaseDeadlock Exception.
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private static final int DEADLOCK_RETRIES = 10;
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// The lock used to provide exclusive access to the thread that
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// close the db (shutdown or clear).
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private ReentrantReadWriteLock dbCloseLock;
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/**
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* Creates a new database or open existing database that will be used
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* to store and retrieve changes from an LDAP server.
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* @param serverId The identifier of the LDAP server.
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* @param baseDn The baseDn of the replication domain.
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* @param replicationServer The ReplicationServer that needs to be shutdown.
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* @param dbenv The Db environment to use to create the db.
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* @throws DatabaseException If a database problem happened.
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*/
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public ReplicationDB(int serverId, String baseDn,
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ReplicationServer replicationServer,
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ReplicationDbEnv dbenv)
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throws DatabaseException
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{
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this.serverId = serverId;
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this.baseDn = baseDn;
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this.dbenv = dbenv;
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this.replicationServer = replicationServer;
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// Get or create the associated ReplicationServerDomain and Db.
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db = dbenv.getOrAddDb(serverId, baseDn,
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replicationServer.getReplicationServerDomain(baseDn,
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true).getGenerationId());
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dbCloseLock = new ReentrantReadWriteLock(true);
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}
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/**
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* add a list of changes to the underlying db.
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*
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* @param changes The list of changes to add to the underlying db.
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*/
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public void addEntries(List<UpdateMsg> changes)
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{
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Transaction txn = null;
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try
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{
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int tries = 0;
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boolean done = false;
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// The database can return a Deadlock Exception if several threads are
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// accessing the database at the same time. This Exception is a
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// transient state, when it happens the transaction is aborted and
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// the operation is attempted again up to DEADLOCK_RETRIES times.
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while ((tries++ < DEADLOCK_RETRIES) && (!done))
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{
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dbCloseLock.readLock().lock();
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try
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{
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txn = dbenv.beginTransaction();
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for (UpdateMsg change : changes)
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{
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DatabaseEntry key = new ReplicationKey(change.getChangeNumber());
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DatabaseEntry data = new ReplicationData(change);
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db.put(txn, key, data);
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}
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txn.commitWriteNoSync();
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txn = null;
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done = true;
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}
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catch (LockConflictException e)
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{
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if (txn != null)
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txn.abort();
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txn = null;
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}
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finally
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{
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dbCloseLock.readLock().unlock();
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}
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}
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if (!done)
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{
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// Could not write to the DB after DEADLOCK_RETRIES tries.
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// This ReplicationServer is not reliable and will be shutdown.
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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logError(mb.toMessage());
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if (txn != null)
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{
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txn.abort();
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}
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replicationServer.shutdown();
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}
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}
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catch (DatabaseException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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if (txn != null)
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{
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try
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{
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txn.abort();
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} catch (DatabaseException e1)
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{
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// can't do much more. The ReplicationServer is shuting down.
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}
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}
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replicationServer.shutdown();
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}
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catch (UnsupportedEncodingException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_UNSUPPORTED_UTF8_ENCODING.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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replicationServer.shutdown();
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if (txn != null)
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{
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try
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{
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txn.abort();
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} catch (DatabaseException e1)
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{
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// can't do much more. The ReplicationServer is shuting down.
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}
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}
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replicationServer.shutdown();
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}
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}
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/**
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* Shutdown the database.
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*/
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public void shutdown()
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{
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try
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{
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dbCloseLock.writeLock().lock();
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try
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{
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db.close();
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}
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finally
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{
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dbCloseLock.writeLock().unlock();
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}
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}
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catch (DatabaseException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(NOTE_EXCEPTION_CLOSING_DATABASE.get(this.toString()));
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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}
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}
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/**
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* Create a cursor that can be used to search or iterate on this
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* ReplicationServer DB.
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*
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* @param changeNumber The ChangeNumber from which the cursor must start.
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* @throws DatabaseException If a database error prevented the cursor
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* creation.
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* @throws Exception if the ReplServerDBCursor creation failed.
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* @return The ReplServerDBCursor.
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*/
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public ReplServerDBCursor openReadCursor(ChangeNumber changeNumber)
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throws DatabaseException, Exception
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{
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return new ReplServerDBCursor(changeNumber);
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}
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/**
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* Create a cursor that can be used to delete some record from this
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* ReplicationServer database.
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*
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* @throws DatabaseException If a database error prevented the cursor
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* creation.
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* @throws Exception if the ReplServerDBCursor creation failed.
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*
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* @return The ReplServerDBCursor.
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*/
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public ReplServerDBCursor openDeleteCursor()
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throws DatabaseException, Exception
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{
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return new ReplServerDBCursor();
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}
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private void closeLockedCursor(Cursor cursor)
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throws DatabaseException
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{
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try
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{
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if (cursor != null)
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cursor.close();
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}
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finally
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{
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dbCloseLock.readLock().unlock();
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}
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}
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/**
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* Read the first Change from the database.
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* @return the first ChangeNumber.
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*/
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public ChangeNumber readFirstChange()
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{
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Cursor cursor = null;
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String str = null;
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try
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{
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dbCloseLock.readLock().lock();
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cursor = db.openCursor(null, null);
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}
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catch (DatabaseException e1)
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{
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dbCloseLock.readLock().unlock();
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return null;
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}
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try
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{
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try
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{
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DatabaseEntry key = new DatabaseEntry();
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DatabaseEntry data = new DatabaseEntry();
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OperationStatus status = cursor.getFirst(key, data, LockMode.DEFAULT);
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if (status != OperationStatus.SUCCESS)
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{
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/* database is empty */
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return null;
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}
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try
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{
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str = new String(key.getData(), "UTF-8");
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} catch (UnsupportedEncodingException e)
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{
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// never happens
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}
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return new ChangeNumber(str);
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}
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finally
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{
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closeLockedCursor(cursor);
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}
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}
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catch (DatabaseException e)
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{
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/* database is faulty */
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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replicationServer.shutdown();
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return null;
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}
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}
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/**
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* Read the last Change from the database.
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* @return the last ChangeNumber.
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*/
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public ChangeNumber readLastChange()
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{
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Cursor cursor = null;
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String str = null;
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try
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{
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dbCloseLock.readLock().lock();
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try
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{
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cursor = db.openCursor(null, null);
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DatabaseEntry key = new DatabaseEntry();
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DatabaseEntry data = new DatabaseEntry();
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OperationStatus status = cursor.getLast(key, data, LockMode.DEFAULT);
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if (status != OperationStatus.SUCCESS)
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{
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/* database is empty */
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return null;
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}
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try
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{
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str = new String(key.getData(), "UTF-8");
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}
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catch (UnsupportedEncodingException e)
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{
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// never happens
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}
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return new ChangeNumber(str);
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}
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finally
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{
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closeLockedCursor(cursor);
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}
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}
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catch (DatabaseException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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replicationServer.shutdown();
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return null;
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}
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}
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/**
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* {@inheritDoc}
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*/
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@Override
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public String toString()
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{
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return serverId + baseDn.toString();
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}
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/**
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* This Class implements a cursor that can be used to browse a
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* replicationServer database.
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*/
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public class ReplServerDBCursor
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{
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private Cursor cursor = null;
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// The transaction that will protect the actions done with the cursor
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// Will be let null for a read cursor
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// Will be set non null for a write cursor
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private Transaction txn = null;
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DatabaseEntry key = new DatabaseEntry();
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DatabaseEntry data = new DatabaseEntry();
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/**
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* Creates a ReplServerDBCursor that can be used for browsing a
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* replicationServer db.
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*
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* @param startingChangeNumber The ChangeNumber from which the cursor must
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* start.
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* @throws Exception When the startingChangeNumber does not exist.
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*/
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private ReplServerDBCursor(ChangeNumber startingChangeNumber)
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throws Exception
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{
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try
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{
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// Take the lock. From now on, whatever error that happen in the life
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// of this cursor should end by unlocking that lock. We must also
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// unlock it when throwing an exception.
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dbCloseLock.readLock().lock();
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cursor = db.openCursor(txn, null);
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if (startingChangeNumber != null)
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{
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key = new ReplicationKey(startingChangeNumber);
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data = new DatabaseEntry();
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if (cursor.getSearchKey(key, data, LockMode.DEFAULT) !=
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OperationStatus.SUCCESS)
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{
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// We could not move the cursor to the expected startingChangeNumber
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if (cursor.getSearchKeyRange(key, data, LockMode.DEFAULT) !=
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OperationStatus.SUCCESS)
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{
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// We could not even move the cursor closed to it => failure
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throw new Exception("ChangeNumber not available");
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}
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else
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{
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// We can move close to the startingChangeNumber.
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// Let's create a cursor from that point.
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DatabaseEntry key = new DatabaseEntry();
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DatabaseEntry data = new DatabaseEntry();
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if (cursor.getPrev(key, data, LockMode.DEFAULT) !=
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OperationStatus.SUCCESS)
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{
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closeLockedCursor(cursor);
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dbCloseLock.readLock().lock();
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cursor = db.openCursor(txn, null);
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}
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}
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}
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}
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}
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catch (Exception e)
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{
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// Unlocking is required before throwing any exception
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closeLockedCursor(cursor);
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throw (e);
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}
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}
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private ReplServerDBCursor() throws DatabaseException
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{
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try
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{
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// We'll go on only if no close or no clear is running
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dbCloseLock.readLock().lock();
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// Create the transaction that will protect whatever done with this
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// write cursor.
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txn = dbenv.beginTransaction();
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cursor = db.openCursor(txn, null);
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}
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catch(DatabaseException e)
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{
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if (txn != null)
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{
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try
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{
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txn.abort();
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}
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catch (DatabaseException dbe)
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{}
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}
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closeLockedCursor(cursor);
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throw (e);
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}
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}
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/**
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* Close the ReplicationServer Cursor.
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*/
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public void close()
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{
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try
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{
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closeLockedCursor(cursor);
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cursor = null;
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}
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catch (DatabaseException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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replicationServer.shutdown();
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}
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if (txn != null)
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{
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try
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{
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txn.commit();
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} catch (DatabaseException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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replicationServer.shutdown();
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}
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}
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}
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/**
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* Abort the Cursor after a Deadlock Exception.
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* This method catch and ignore the DeadlockException because
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* this must be done when aborting a cursor after a DeadlockException
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* (per the Cursor documentation).
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* This should not be used in any other case.
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*/
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public void abort()
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{
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if (cursor == null)
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return;
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try
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{
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closeLockedCursor(cursor);
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cursor = null;
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}
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catch (LockConflictException e1)
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{
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// The DB documentation states that a DeadlockException
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// on the close method of a cursor that is aborting should
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// be ignored.
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}
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catch (DatabaseException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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replicationServer.shutdown();
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}
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if (txn != null)
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{
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try
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{
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txn.abort();
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} catch (DatabaseException e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_CHANGELOG_SHUTDOWN_DATABASE_ERROR.get());
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mb.append(stackTraceToSingleLineString(e));
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logError(mb.toMessage());
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replicationServer.shutdown();
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}
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}
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}
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/**
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* Get the next ChangeNumber in the database from this Cursor.
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*
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* @return The next ChangeNumber in the database from this cursor.
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* @throws DatabaseException In case of underlying database problem.
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*/
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public ChangeNumber nextChangeNumber() throws DatabaseException
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{
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OperationStatus status = cursor.getNext(key, data, LockMode.DEFAULT);
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if (status != OperationStatus.SUCCESS)
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{
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return null;
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}
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try
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{
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String csnString = new String(key.getData(), "UTF-8");
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return new ChangeNumber(csnString);
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} catch (UnsupportedEncodingException e)
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{
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// can't happen
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return null;
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}
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}
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/**
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* Get the next UpdateMsg from this cursor.
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*
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* @return the next UpdateMsg.
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*/
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public UpdateMsg next()
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{
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UpdateMsg currentChange = null;
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while (currentChange == null)
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{
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try
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{
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OperationStatus status = cursor.getNext(key, data, LockMode.DEFAULT);
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if (status != OperationStatus.SUCCESS)
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{
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return null;
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}
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} catch (DatabaseException e)
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{
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return null;
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}
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try {
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currentChange = ReplicationData.generateChange(data.getData());
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} catch (Exception e) {
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/*
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* An error happening trying to convert the data from the
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* replicationServer database to an Update Message.
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* This can only happen if the database is corrupted.
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* There is not much more that we can do at this point except trying
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* to continue with the next record.
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* In such case, it is therefore possible that we miss some changes.
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* TODO. log an error message.
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* TODO : REPAIR : Such problem should be handled by the
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* repair functionality.
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*/
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}
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}
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return currentChange;
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}
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/**
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* Delete the record at the current cursor position.
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*
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* @throws DatabaseException In case of database problem.
|
*/
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public void delete() throws DatabaseException
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{
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cursor.delete();
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}
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} // ReplServerDBCursor
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/**
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* Clears this change DB from the changes it contains.
|
*
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* @throws Exception Throws an exception it occurs.
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* @throws DatabaseException Throws a DatabaseException when it occurs.
|
*/
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public void clear() throws Exception, DatabaseException
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{
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// The coming users will be blocked until the clear is done
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dbCloseLock.writeLock().lock();
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try
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{
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String dbName = db.getDatabaseName();
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// Clears the reference to this serverID
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dbenv.clearServerId(baseDn, serverId);
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// Closing is requested by the Berkeley DB before truncate
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db.close();
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// Clears the changes
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dbenv.clearDb(dbName);
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// RE-create the db
|
db = dbenv.getOrAddDb(serverId, baseDn, (long)-1);
|
}
|
catch(Exception e)
|
{
|
MessageBuilder mb = new MessageBuilder();
|
mb.append(ERR_ERROR_CLEARING_DB.get(this.toString(),
|
e.getMessage() + " " +
|
stackTraceToSingleLineString(e)));
|
logError(mb.toMessage());
|
}
|
finally
|
{
|
// Relax the waiting users
|
dbCloseLock.writeLock().unlock();
|
}
|
}
|
}
|
