/
CheckPointer.java
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/
CheckPointer.java
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/*
* Copyright (c) 2002-2015 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.kernel.impl.transaction.log.checkpoint;
import java.io.IOException;
/**
* This interface represent a check pointer which is responsible to write check points in the transaction log.
*/
public interface CheckPointer
{
/**
* This method will verify that the conditions for triggering a check point hold and in such a case it will write
* a check point in the transaction log.
*
* This method does NOT handle concurrency since there should be only one check point thread running.
*
* @throws IOException if writing the check point fails
*/
void checkPointIfNeeded() throws IOException;
/**
* This method forces the write of a check point in the transaction log.
*
* It is mostly used for testing purpose and to force a check point when shutting down the database.
*
* @throws IOException if writing the check point fails
*/
void forceCheckPoint() throws IOException;
class PrintFormat
{
public static String prefix( long transactionId )
{
return "Check Pointing [" + transactionId + "]: ";
}
}
}