package org.apache.torque.oid;
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.torque.adapter.DB;
import org.apache.torque.util.SQLBuilder;
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 for
* getting an id prior to inserting a row into the database.
*
* @author <a href="mailto:jmcnally@collab.net">John D. McNally</a>
* @version $Id: SequenceIdGenerator.java 473821 2006-11-11 22:37:25Z tv $
*/
public class SequenceIdGenerator implements IdGenerator
{
/** The log. */
private static Log log = LogFactory.getLog(SequenceIdGenerator.class);
/** the adapter that knows the correct sql syntax */
private DB dbAdapter;
/** The internal name of the Database that this Generator is connected to */
private String name = null;
/**
* Creates an IdGenerator which will work with the specified database.
*
* @param dbAdapter the adapter that knows the correct sql syntax.
* @param name The name of the datasource to find the correct schema
*/
public SequenceIdGenerator(final DB dbAdapter, final String name)
{
this.dbAdapter = dbAdapter;
this.name = name;
}
/**
* Retrieves an id as an int.
*
* @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();
}
/**
* Retrieves an id as an long.
*
* @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();
}
/**
* Retrieves an id as a BigDecimal.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return A BigDecimal id
* @exception Exception Database error.
*/
public BigDecimal getIdAsBigDecimal(Connection connection, Object keyInfo)
throws Exception
{
return getIdAsVillageValue(connection, keyInfo).asBigDecimal();
}
/**
* Retrieves an id as an String.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return A String id
* @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 true;
}
/**
* A flag to determine the timing of the id generation
*
* @return a <code>boolean</code> value
*/
public boolean isPostInsert()
{
return false;
}
/**
* A flag to determine whether a Connection is required to
* generate an id.
*
* @return a <code>boolean</code> value
*/
public boolean isConnectionRequired()
{
return true;
}
/**
* Retrieves an id as a Village Value.
*
* @param connection A Connection.
* @param keyInfo an Object that contains additional info.
* @return A Village Value id.
* @exception Exception Database error.
*/
private Value getIdAsVillageValue(Connection connection, Object keyInfo)
throws Exception
{
String sequenceName = SQLBuilder.getFullTableName(String.valueOf(keyInfo), name);
String idSql = dbAdapter.getIDMethodSQL(sequenceName);
if (log.isDebugEnabled())
{
log.debug(idSql);
}
// Execute the query.
QueryDataSet qds = new QueryDataSet(connection, idSql);
Record rec;
try
{
qds.fetchRecords(1);
rec = qds.getRecord(0); // Records are 0 based.
}
finally
{
qds.close();
}
return rec.getValue(1); // Values are 1 based.
}
}