package org.apache.torque.oid;
/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* 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.
*/
import java.math.BigDecimal;
import java.sql.Connection;
import org.apache.torque.adapter.DB;
import com.workingdogs.village.QueryDataSet;
import com.workingdogs.village.Record;
import com.workingdogs.village.Value;
/**
* This generator works with databases that have an sql syntax that
* allows the retrieval of the last id used to insert a row for a
* Connection.
*
* @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
* @version $Id: AutoIncrementIdGenerator.java,v 1.5.4.2 2004/05/20 04:36:07 seade Exp $
*/
public class AutoIncrementIdGenerator implements IdGenerator
{
/** the adapter that knows the correct sql syntax */
private DB dbAdapter;
/**
* Creates an IdGenerator which will work with the specified database.
*
* @param adapter the adapter that knows the correct sql syntax.
*/
public AutoIncrementIdGenerator(DB adapter)
{
dbAdapter = adapter;
}
/**
* Returns the last ID used by this connection.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return An int with the value for the id.
* @exception Exception Database error.
*/
public int getIdAsInt(Connection connection, Object keyInfo)
throws Exception
{
return getIdAsVillageValue(connection, keyInfo).asInt();
}
/**
* Returns the last ID used by this connection.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return A long with the value for the id.
* @exception Exception Database error.
*/
public long getIdAsLong(Connection connection, Object keyInfo)
throws Exception
{
return getIdAsVillageValue(connection, keyInfo).asLong();
}
/**
* Returns the last ID used by this connection.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return A BigDecimal with the last value auto-incremented as a
* result of an insert.
* @exception Exception Database error.
*/
public BigDecimal getIdAsBigDecimal(Connection connection, Object keyInfo)
throws Exception
{
return getIdAsVillageValue(connection, keyInfo).asBigDecimal();
}
/**
* Returns the last ID used by this connection.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return A String with the last value auto-incremented as a
* result of an insert.
* @exception Exception Database error.
*/
public String getIdAsString(Connection connection, Object keyInfo)
throws Exception
{
return getIdAsVillageValue(connection, keyInfo).asString();
}
/**
* A flag to determine the timing of the id generation
*
* @return a <code>boolean</code> value
*/
public boolean isPriorToInsert()
{
return false;
}
/**
* A flag to determine the timing of the id generation
*
* @return a <code>boolean</code> value
*/
public boolean isPostInsert()
{
return true;
}
/**
* A flag to determine whether a Connection is required to
* generate an id.
*
* @return a <code>boolean</code> value
*/
public final boolean isConnectionRequired()
{
return true;
}
/**
* Returns the last ID used by this connection.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return A Village Value with the last value auto-incremented as a
* result of an insert.
* @exception Exception Database error.
*/
private Value getIdAsVillageValue(Connection connection, Object keyInfo)
throws Exception
{
String idSQL = dbAdapter.getIDMethodSQL(keyInfo);
Value id = null;
QueryDataSet qds = null;
try
{
qds = new QueryDataSet(connection, idSQL);
qds.fetchRecords(1);
Record rec = qds.getRecord(0);
id = rec.getValue(1);
}
finally
{
if (qds != null)
{
qds.close();
}
}
return id;
}
}