/*---------------- FILE HEADER ------------------------------------------
This file is part of deegree.
Copyright (C) 2001-2006 by:
EXSE, Department of Geography, University of Bonn
http://www.giub.uni-bonn.de/deegree/
lat/lon GmbH
http://www.lat-lon.de
This library 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 2.1 of the License, or (at your option) any later version.
This library 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 this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Contact:
Andreas Poth
lat/lon GmbH
Aennchenstr. 19
53115 Bonn
Germany
E-Mail: poth@lat-lon.de
Prof. Dr. Klaus Greve
Department of Geography
University of Bonn
Meckenheimer Allee 166
53115 Bonn
Germany
E-Mail: greve@giub.uni-bonn.de
---------------------------------------------------------------------------*/
package org.deegree.io;
import java.sql.Connection;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;
/**
* class to manage a database connection pool. this is part of the combination
* of the object pool pattern an the singelton pattern.
*
* @author <a href="mailto:poth@lat-lon.de">Andreas Poth </a>
* @version 07.02.2001
*/
public class DBConnectionPool {
private static DBConnectionPool instance = null;
private Map pools = null;
/**
* Creates a new DBConnectionPool object.
*/
private DBConnectionPool() {
pools = new HashMap();
}
/**
* realize singelton pattern using double checked locking pattern.
*
* @return an instance of the data base pool. it is gauranteed that there
* exists only one instance of pool for each submitted class name.
*
*/
public static DBConnectionPool getInstance() {
if (instance == null) {
synchronized (DBConnectionPool.class) {
if (instance == null) {
instance = new DBConnectionPool();
}
}
}
return instance;
}
/**
* get an object from the object pool
*/
public synchronized Connection acquireConnection(final String driver,
final String database, final String user, final String password)
throws DBPoolException {
String q = driver + database + user + password;
DBPool pool = null;
if (pools.get(q) == null) {
pool = new DBPool(driver, database, user, password);
pools.put(q, pool);
} else {
pool = (DBPool) pools.get(q);
}
return (Connection) pool.acquireObject();
}
/**
* get an object from the object pool
*/
public synchronized Connection acquireConnection(final String driver,
final String database, final Properties properties)
throws DBPoolException {
String q = driver + database + properties.toString();
if (pools.get(q) == null) {
DBPool pool = new DBPool(driver, database, properties);
pools.put(q, pool);
return (Connection) pool.acquireObject();
}
DBPool pool = (DBPool) pools.get(q);
return (Connection) pool.acquireObject();
}
/**
* releases a connection back to the pool
*/
public synchronized void releaseConnection(final Connection con,
final String driver, final String database, final String user,
final String password) throws DBPoolException {
String q = driver + database + user + password;
DBPool pool = (DBPool) pools.get(q);
try {
pool.releaseObject(con);
} catch (Exception e) {
throw new DBPoolException( "could not release connection", e );
}
}
/**
* releases a connection back to the pool
*/
public synchronized void releaseConnection(final Connection con,
final String driver, final String database,
final Properties properties) throws Exception {
String q = driver + database + properties.toString();
DBPool pool = (DBPool) pools.get(q);
pool.releaseObject(con);
}
}/* ********************************************************************
Changes to this class. What the people have been up to:
$Log: DBConnectionPool.java,v $
Revision 1.12 2006/07/12 14:46:18 poth
comment footer added
********************************************************************** */