/*
* Copyright (C) 2012, Katy Hilgenberg.
* Special acknowledgments to: Knowledge & Data Engineering Group, University of Kassel (http://www.kde.cs.uni-kassel.de).
* Contact: sdcf@cs.uni-kassel.de
*
* This file is part of the SDCFramework (Sensor Data Collection Framework) project.
*
* The SDCFramework is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* The SDCFramework 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 Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the SDCFramework. If not, see <http://www.gnu.org/licenses/>.
*/
package de.unikassel.android.sdcframework.persistence;
import java.security.InvalidParameterException;
import de.unikassel.android.sdcframework.persistence.facade.PersistentStorageManager;
import de.unikassel.android.sdcframework.util.Logger;
/**
* Implementation of a the database full strategy which does delete old samples. <br/>
* <br/>
* This strategy does delete the configured count of samples in the database.
* Normally the oldest samples will be selected first, but if
* configured, the oldest samples with lowest priority will be preferred for deletion.
*
* @author Katy Hilgenberg
*
*/
public final class DeleteSamplesStrategy
extends AbstractDatabaseFullStrategy
{
/**
* The count of samples to delete
*/
protected final int countToDelete;
/**
* The count of samples to delete
*/
protected final boolean lowestPriorityFirst;
/**
* Constructor
*
* @param countToDelete
* the count of samples to delete
* @param lowestPriorityFirst
* if true the oldest samples with lowest priority will be deleted
* first
*/
public DeleteSamplesStrategy( int countToDelete, boolean lowestPriorityFirst )
{
super();
this.countToDelete = countToDelete;
this.lowestPriorityFirst = lowestPriorityFirst;
if ( countToDelete < 0 )
throw new InvalidParameterException(
"countToDelete has to be more or equal to 0" );
}
/**
* Getter for the record count to delete
*
* @return the the record count to delete
*/
public final int getCountToDelete()
{
return countToDelete;
}
/*
* (non-Javadoc)
*
* @see
* de.unikassel.android.sdcframework.persistence.AbstractDatabaseFullStrategy
* #execute
* (de.unikassel.android.sdcframework.persistence.facade.PersistentStorageManager
* )
*/
@Override
public final boolean process( PersistentStorageManager storageManager )
{
long countToDelete =
Math.min( storageManager.getRecordCountInDatabase(), this.countToDelete );
long cntDeletedSamples =
storageManager.doDeleteOldestSamplesInDatabase( countToDelete,
lowestPriorityFirst );
if ( cntDeletedSamples > 0L )
{
Logger.getInstance().info( this,
"" + cntDeletedSamples + " samples deleted!" );
Logger.getInstance().debug(
this,
"Total record count in database: "
+ storageManager.getRecordCountInDatabase() );
}
return super.process( storageManager );
}
/**
* Getter for the priority basted deletion flag
*
* @return true if deletion is done for samples with lowest priority first.
* Otherwise it is done for the oldest samples
*/
public Object isDeletingPriorityBased()
{
return lowestPriorityFirst;
}
}