/**********************************************************************
Copyright (c) 2005 Erik Bengtson and others. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
Contributors:
...
**********************************************************************/
package org.datanucleus.store.rdbms.valuegenerator;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import org.datanucleus.store.rdbms.RDBMSStoreManager;
import org.datanucleus.store.rdbms.SQLController;
import org.datanucleus.store.rdbms.adapter.RDBMSAdapter;
import org.datanucleus.store.valuegenerator.ValueGenerationBlock;
import org.datanucleus.store.valuegenerator.ValueGenerationException;
/**
* Generator for values using datastore-based UUID generation.
*/
public final class DatastoreUUIDHexGenerator extends AbstractRDBMSGenerator
{
/**
* Constructor.
* @param name Symbolic name for this generator
* @param props Properties defining the behaviour of this generator
*/
public DatastoreUUIDHexGenerator(String name, Properties props)
{
super(name, props);
allocationSize = 10;
if (properties != null)
{
if (properties.get("key-cache-size") != null)
{
try
{
allocationSize = Integer.parseInt((String)properties.get("key-cache-size"));
}
catch (Exception e)
{
throw new ValueGenerationException(LOCALISER.msg("040006",properties.get("key-cache-size")));
}
}
}
}
/**
* Accessor for the storage class for POIDs generated with this generator.
* @return Storage class (in this case String.class)
*/
public static Class getStorageClass()
{
return String.class;
}
/**
* Reserve a block of ids.
* @param size Block size
* @return The reserved block
*/
protected synchronized ValueGenerationBlock reserveBlock(long size)
{
PreparedStatement ps = null;
ResultSet rs = null;
List oid = new ArrayList();
RDBMSStoreManager srm = (RDBMSStoreManager)storeMgr;
SQLController sqlControl = srm.getSQLController();
try
{
// Find the next ID from the database
RDBMSAdapter dba = (RDBMSAdapter) srm.getDatastoreAdapter();
String stmt = dba.getSelectNewUUIDStmt();
ps = sqlControl.getStatementForQuery(connection, stmt);
for (int i=1; i<size; i++)
{
rs = sqlControl.executeStatementQuery(connection, stmt, ps);
String nextId;
if (rs.next())
{
nextId = rs.getString(1);
oid.add(nextId);
}
}
return new ValueGenerationBlock(oid);
}
catch (SQLException e)
{
throw new ValueGenerationException(LOCALISER.msg("040008",e.getMessage()));
}
finally
{
try
{
if (rs != null)
{
rs.close();
}
if (ps != null)
{
sqlControl.closeStatement(connection, ps);
}
}
catch (SQLException e)
{
// non-recoverable error
}
}
}
}