/*
* 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.
*/
package org.apache.avalon.excalibur.datasource.cluster;
import java.sql.Connection;
import java.sql.SQLException;
import org.apache.avalon.excalibur.datasource.DataSourceComponent;
import org.apache.avalon.excalibur.datasource.NoValidConnectionException;
import org.apache.avalon.framework.activity.Disposable;
import org.apache.avalon.framework.activity.Initializable;
import org.apache.avalon.framework.configuration.Configurable;
import org.apache.avalon.framework.configuration.Configuration;
import org.apache.avalon.framework.configuration.ConfigurationException;
import org.apache.avalon.framework.logger.AbstractLogEnabled;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.avalon.framework.service.ServiceSelector;
import org.apache.avalon.framework.service.Serviceable;
import org.apache.avalon.framework.thread.ThreadSafe;
/**
* @author <a href="mailto:dev@avalon.apache.org">Avalon Development Team</a>
* @version CVS $Revision: 1.4 $ $Date: 2004/02/28 11:47:20 $
* @since 4.1
*/
public abstract class AbstractDataSourceCluster
extends AbstractLogEnabled
implements Serviceable, Configurable, Initializable, Disposable, ThreadSafe
{
protected int m_size;
private String[] m_dataSourceNames;
private ServiceSelector m_dbSelector;
private DataSourceComponent[] m_dataSources;
/*---------------------------------------------------------------
* Constructors
*-------------------------------------------------------------*/
public AbstractDataSourceCluster()
{
}
/*---------------------------------------------------------------
* AbstractDataSourceCluster Methods
*-------------------------------------------------------------*/
/**
* Returns the number of DataSources in the cluster.
*
* @return size of the cluster.
*/
public int getClusterSize()
{
return m_size;
}
/**
* Gets a Connection to a database given an index.
*
* @param index Index of the DataSource for which a connection is to be returned.
*
* @throws NoValidConnectionException when there is no valid Connection wrapper
* available in the classloader or when the index is not valid.
*
* @throws NoValidConnectionException when there are no more available
* Connections in the pool.
*/
public Connection getConnectionForIndex( int index ) throws SQLException
{
if( ( index < 0 ) || ( index >= m_size ) )
{
throw new NoValidConnectionException(
"index (" + index + ") must be in the range 0 to " + ( m_size - 1 ) );
}
return m_dataSources[ index ].getConnection();
}
/*---------------------------------------------------------------
* Composable Methods
*-------------------------------------------------------------*/
/**
* Called by the Container to tell the component which ComponentLocator
* is controlling it.
*
* @param manager which curently owns the component.
* @avalon.dependency type="org.apache.avalon.excalibur.datasource.DataSourceComponent"
*/
public void service( final ServiceManager manager )
throws ServiceException
{
m_dbSelector =
(ServiceSelector)manager.lookup( DataSourceComponent.ROLE + "Selector" );
}
/*---------------------------------------------------------------
* Configurable Methods
*-------------------------------------------------------------*/
/**
* Called by the Container to configure the component.
*
* @param configuration configuration info used to setup the component.
*
* @throws ConfigurationException if there are any problems with the configuration.
*/
public void configure( Configuration configuration ) throws ConfigurationException
{
// Get the size
m_size = configuration.getAttributeAsInteger( "size" );
if( m_size < 1 )
{
throw new ConfigurationException(
"Invalid value (" + m_size + ") for size attribute." );
}
// Read in the data source names.
m_dataSourceNames = new String[ m_size ];
Configuration[] dataSourceConfigs = configuration.getChildren( "dbpool" );
for( int i = 0; i < dataSourceConfigs.length; i++ )
{
int index = dataSourceConfigs[ i ].getAttributeAsInteger( "index" );
if( ( index < 0 ) || ( index >= m_size ) )
{
throw new ConfigurationException( "The dbpool with index=\"" + index +
"\" is invalid. Index must be in the range 0 to " + ( m_size - 1 ) );
}
if( m_dataSourceNames[ index ] != null )
{
throw new ConfigurationException( "Only one dbpool with index=\"" + index +
"\" can be defined." );
}
m_dataSourceNames[ index ] = dataSourceConfigs[ i ].getValue();
}
// Make sure that all of the dbpools were defined
for( int i = 0; i < m_dataSourceNames.length; i++ )
{
if( m_dataSourceNames[ i ] == null )
{
throw new ConfigurationException( "Expected a dbpool with index=\"" + i + "\"" );
}
}
}
/*---------------------------------------------------------------
* Initializable Methods
*-------------------------------------------------------------*/
/**
* Called by the Container to initialize the component.
*
* @throws Exception if there were any problems durring initialization.
*/
public void initialize() throws Exception
{
// Get references to a data sources
m_dataSources = new DataSourceComponent[ m_size ];
for( int i = 0; i < m_dataSourceNames.length; i++ )
{
m_dataSources[ i ] = (DataSourceComponent)m_dbSelector.select( m_dataSourceNames[ i ] );
}
}
/*---------------------------------------------------------------
* Disposable Methods
*-------------------------------------------------------------*/
/**
* Called by the Container to dispose the component.
*/
public void dispose()
{
// Free up the data source
if( m_dbSelector != null )
{
if( m_dataSources != null )
{
for( int i = 0; i < m_dataSources.length; i++ )
{
if( m_dataSources[ i ] != null )
{
m_dbSelector.release( m_dataSources[ i ] );
}
}
m_dataSources = null;
}
m_dbSelector = null;
}
}
}