/*
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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 2009 Sun Microsystems, Inc.
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* Portions Copyright 2011-2013 ForgeRock AS
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*/
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package org.opends.server.replication.server.changelog.je;
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import java.io.Closeable;
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import java.util.concurrent.locks.ReadWriteLock;
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import java.util.concurrent.locks.ReentrantReadWriteLock;
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import org.opends.messages.MessageBuilder;
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import org.opends.server.loggers.debug.DebugTracer;
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import org.opends.server.replication.server.changelog.api.*;
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import org.opends.server.types.DebugLogLevel;
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import com.sleepycat.je.*;
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import static com.sleepycat.je.LockMode.*;
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import static com.sleepycat.je.OperationStatus.*;
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import static org.opends.messages.ReplicationMessages.*;
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import static org.opends.server.loggers.ErrorLogger.*;
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import static org.opends.server.loggers.debug.DebugLogger.*;
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import static org.opends.server.util.StaticUtils.*;
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/**
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* This class implements the interface between the underlying database
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* and the {@link JEChangeNumberIndexDB} 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 DraftCNDB
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{
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private static final DebugTracer TRACER = getTracer();
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private Database db;
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private ReplicationDbEnv dbenv;
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/**
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* The lock used to provide exclusive access to the thread that close the db
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* (shutdown or clear).
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*/
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private final ReadWriteLock dbCloseLock = new ReentrantReadWriteLock(true);
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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 dbenv The Db environment to use to create the db.
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* @throws ChangelogException If a database problem happened
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*/
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public DraftCNDB(ReplicationDbEnv dbenv) throws ChangelogException
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{
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this.dbenv = dbenv;
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// Get or create the associated ReplicationServerDomain and Db.
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db = dbenv.getOrCreateCNIndexDB();
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}
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/**
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* Add a record to the database.
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*
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* @param record
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* the provided {@link ChangeNumberIndexRecord} to be stored.
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* @throws ChangelogException
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* If a database problem happened
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*/
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public void addRecord(ChangeNumberIndexRecord record)
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throws ChangelogException
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{
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try
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{
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final long changeNumber = record.getChangeNumber();
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DatabaseEntry key = new ReplicationDraftCNKey(changeNumber);
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DatabaseEntry data = new DraftCNData(changeNumber,
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record.getPreviousCookie(), record.getBaseDN().toNormalizedString(),
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record.getCSN());
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// Use a transaction so that we can override durability.
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Transaction txn = null;
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dbCloseLock.readLock().lock();
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try
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{
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// If the DB has been closed then return immediately.
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if (isDBClosed())
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{
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return;
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}
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txn = dbenv.beginTransaction();
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db.put(txn, key, data);
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txn.commit(Durability.COMMIT_WRITE_NO_SYNC);
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}
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finally
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{
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JEUtils.abort(txn);
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dbCloseLock.readLock().unlock();
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}
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}
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catch (DatabaseException e)
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{
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throw new ChangelogException(e);
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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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dbCloseLock.writeLock().lock();
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try
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{
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db.close();
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db = null;
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}
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catch (DatabaseException e)
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{
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logError(NOTE_EXCEPTION_CLOSING_DATABASE.get(toString(),
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stackTraceToSingleLineString(e)));
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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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/**
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* Create a cursor that can be used to search or iterate on this DB.
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*
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* @param changeNumber The change number from which the cursor must start.
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* @return The ReplServerDBCursor
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* @throws ChangelogException If a database error prevented the cursor
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* creation.
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*/
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public DraftCNDBCursor openReadCursor(long changeNumber)
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throws ChangelogException
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{
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return new DraftCNDBCursor(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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* @return The ReplServerDBCursor
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* @throws ChangelogException If a database error prevented the cursor
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* creation.
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*/
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public DraftCNDBCursor openDeleteCursor() throws ChangelogException
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{
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return new DraftCNDBCursor();
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}
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private void closeLockedCursor(Cursor cursor)
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{
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try
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{
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close(cursor);
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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, 0 when none.
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*
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* @return the first change number.
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* @throws ChangelogException
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* if a database problem occurred
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*/
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public ChangeNumberIndexRecord readFirstRecord() throws ChangelogException
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{
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try
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{
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dbCloseLock.readLock().lock();
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Cursor cursor = null;
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try
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{
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// If the DB has been closed then return immediately.
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if (isDBClosed())
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{
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return null;
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}
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cursor = db.openCursor(null, null);
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ReplicationDraftCNKey key = new ReplicationDraftCNKey();
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DatabaseEntry entry = new DatabaseEntry();
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if (cursor.getFirst(key, entry, LockMode.DEFAULT) != SUCCESS)
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{
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return null;
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}
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return newCNIndexRecord(key, entry);
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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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throw new ChangelogException(e);
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}
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}
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private ChangeNumberIndexRecord newCNIndexRecord(ReplicationDraftCNKey key,
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DatabaseEntry data) throws ChangelogException
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{
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return new DraftCNData(key.getChangeNumber(), data.getData()).getRecord();
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}
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/**
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* Return the record count.
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* @return the record count.
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*/
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public long count()
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{
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dbCloseLock.readLock().lock();
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try
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{
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// If the DB has been closed then return immediately.
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if (isDBClosed())
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{
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return 0;
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}
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return db.count();
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}
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catch (DatabaseException e)
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{
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TRACER.debugCaught(DebugLogLevel.ERROR, e);
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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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return 0;
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}
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/**
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* Read the last change number from the database.
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*
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* @return the last change number.
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* @throws ChangelogException
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* if a database problem occurred
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*/
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public ChangeNumberIndexRecord readLastRecord() throws ChangelogException
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{
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try
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{
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dbCloseLock.readLock().lock();
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Cursor cursor = null;
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try
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{
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// If the DB has been closed then return immediately.
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if (isDBClosed())
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{
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return null;
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}
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cursor = db.openCursor(null, null);
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ReplicationDraftCNKey key = new ReplicationDraftCNKey();
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DatabaseEntry entry = new DatabaseEntry();
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if (cursor.getLast(key, entry, LockMode.DEFAULT) != SUCCESS)
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{
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return null;
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}
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return newCNIndexRecord(key, entry);
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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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throw new ChangelogException(e);
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}
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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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}
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/**
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* This Class implements a cursor that can be used to browse the database.
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*/
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public class DraftCNDBCursor implements Closeable
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{
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private final Cursor cursor;
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/**
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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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*/
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private final Transaction txn;
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private final ReplicationDraftCNKey key;
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private final DatabaseEntry entry = new DatabaseEntry();
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private ChangeNumberIndexRecord record;
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private boolean isClosed = false;
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/**
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* Creates a cursor that can be used for browsing the db.
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*
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* @param startChangeNumber
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* the change number from which the cursor must start.
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* @throws ChangelogException
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* If a database problem happened
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*/
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private DraftCNDBCursor(long startChangeNumber) throws ChangelogException
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{
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this.key = new ReplicationDraftCNKey(startChangeNumber);
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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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boolean cursorHeld = false;
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Cursor localCursor = null;
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try
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{
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// If the DB has been closed then create empty cursor.
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if (isDBClosed())
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{
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isClosed = true;
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txn = null;
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cursor = null;
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return;
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}
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localCursor = db.openCursor(null, null);
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if (startChangeNumber >= 0)
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{
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if (localCursor.getSearchKey(key, entry, LockMode.DEFAULT) != SUCCESS)
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{
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// We could not move the cursor to the expected startChangeNumber
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if (localCursor.getSearchKeyRange(key, entry, DEFAULT) != SUCCESS)
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{
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// We could not even move the cursor close to it
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// => return an empty cursor
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isClosed = true;
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txn = null;
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cursor = null;
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return;
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}
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if (localCursor.getPrev(key, entry, LockMode.DEFAULT) != SUCCESS)
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{
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localCursor.close();
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localCursor = db.openCursor(null, null);
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}
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else
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{
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record = newCNIndexRecord(this.key, entry);
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}
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}
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else
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{
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record = newCNIndexRecord(this.key, entry);
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}
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}
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this.txn = null;
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this.cursor = localCursor;
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cursorHeld = true;
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}
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catch (DatabaseException e)
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{
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throw new ChangelogException(e);
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}
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finally
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{
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if (!cursorHeld)
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{
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// Do not keep a readLock on the DB when this class does not hold a DB
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// cursor. Either an exception was thrown or no cursor could be opened
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// for some reason.
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closeLockedCursor(localCursor);
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}
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}
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}
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private DraftCNDBCursor() throws ChangelogException
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{
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Transaction localTxn = null;
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Cursor localCursor = null;
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this.key = new ReplicationDraftCNKey();
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// We'll go on only if no close or no clear is running
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boolean cursorHeld = false;
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dbCloseLock.readLock().lock();
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try
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{
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// If the DB has been closed then create empty cursor.
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if (isDBClosed())
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{
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isClosed = true;
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txn = null;
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cursor = null;
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return;
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}
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// Create the transaction that will protect whatever done with this
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// write cursor.
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localTxn = dbenv.beginTransaction();
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localCursor = db.openCursor(localTxn, null);
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this.txn = localTxn;
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this.cursor = localCursor;
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cursorHeld = true;
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}
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catch (DatabaseException e)
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{
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TRACER.debugCaught(DebugLogLevel.ERROR, e);
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JEUtils.abort(localTxn);
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throw new ChangelogException(e);
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}
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catch (ChangelogException e)
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{
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TRACER.debugCaught(DebugLogLevel.ERROR, e);
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JEUtils.abort(localTxn);
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throw e;
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}
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finally
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{
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if (!cursorHeld)
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{
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// Do not keep a readLock on the DB when this class does not hold a DB
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// cursor. Either an exception was thrown or no cursor could be opened
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// for some reason.
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closeLockedCursor(localCursor);
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}
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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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@Override
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public void close()
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{
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synchronized (this)
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{
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if (isClosed)
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{
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return;
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}
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isClosed = true;
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}
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closeLockedCursor(cursor);
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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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}
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catch (DatabaseException e)
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{
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dbenv.shutdownOnException(e);
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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 DatabaseException.
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* This method catch and ignore the DatabaseException because
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* this must be done when aborting a cursor after a DatabaseException
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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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synchronized (this)
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{
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if (isClosed)
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{
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return;
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}
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isClosed = true;
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}
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closeLockedCursor(cursor);
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JEUtils.abort(txn);
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}
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/**
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* Returns the {@link ChangeNumberIndexRecord} at the current position of
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* the cursor.
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*
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* @return The current {@link ChangeNumberIndexRecord}.
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*/
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public ChangeNumberIndexRecord currentRecord()
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{
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if (isClosed)
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{
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return null;
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}
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return record;
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}
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/**
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* Go to the next record on the cursor.
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*
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* @return the next record on this cursor.
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* @throws ChangelogException
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* If a database problem happened
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*/
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public boolean next() throws ChangelogException
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{
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// first wipe old entry
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record = null;
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if (isClosed)
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{
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return false;
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}
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try {
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OperationStatus status = cursor.getNext(key, entry, LockMode.DEFAULT);
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if (status == OperationStatus.SUCCESS)
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{
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record = newCNIndexRecord(this.key, entry);
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return true;
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}
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return false;
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}
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catch (DatabaseException e)
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{
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throw new ChangelogException(e);
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}
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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 ChangelogException
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* If a database problem happened
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*/
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public void delete() throws ChangelogException
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{
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if (isClosed)
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{
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throw new IllegalStateException("DraftCNDB already closed");
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}
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try
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{
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cursor.delete();
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}
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catch (DatabaseException e)
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{
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throw new ChangelogException(e);
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}
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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() + " currentRecord=" + record;
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}
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}
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/**
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* Clears this change DB from the changes it contains.
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*
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* @throws ChangelogException
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* If a database problem happened
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*/
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public void clear() throws ChangelogException
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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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// If the DB has been closed then return immediately.
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if (isDBClosed())
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{
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return;
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}
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final Database oldDb = db;
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db = null; // In case there's a failure between here and recreation.
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dbenv.clearDb(oldDb);
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// RE-create the db
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db = dbenv.getOrCreateCNIndexDB();
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}
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catch(Exception e)
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{
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MessageBuilder mb = new MessageBuilder();
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mb.append(ERR_ERROR_CLEARING_DB.get(toString(),
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e.getMessage() + " " + stackTraceToSingleLineString(e)));
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logError(mb.toMessage());
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}
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finally
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{
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// Relax the waiting users
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dbCloseLock.writeLock().unlock();
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}
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}
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/**
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* Returns {@code true} if the DB is closed. This method assumes that either
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* the db read/write lock has been taken.
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*
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* @return {@code true} if the DB is closed.
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*/
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private boolean isDBClosed()
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{
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return db == null || !db.getEnvironment().isValid();
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}
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}
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