001 //$HeadURL: svn+ssh://rbezema@svn.wald.intevation.org/deegree/base/tags/2.1/src/org/deegree/io/DBConnectionPool.java $
002 /*---------------- FILE HEADER ------------------------------------------
003
004 This file is part of deegree.
005 Copyright (C) 2001-2007 by:
006 EXSE, Department of Geography, University of Bonn
007 http://www.giub.uni-bonn.de/deegree/
008 lat/lon GmbH
009 http://www.lat-lon.de
010
011 This library is free software; you can redistribute it and/or
012 modify it under the terms of the GNU Lesser General Public
013 License as published by the Free Software Foundation; either
014 version 2.1 of the License, or (at your option) any later version.
015
016 This library is distributed in the hope that it will be useful,
017 but WITHOUT ANY WARRANTY; without even the implied warranty of
018 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
019 Lesser General Public License for more details.
020
021 You should have received a copy of the GNU Lesser General Public
022 License along with this library; if not, write to the Free Software
023 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
024
025 Contact:
026
027 Andreas Poth
028 lat/lon GmbH
029 Aennchenstr. 19
030 53115 Bonn
031 Germany
032 E-Mail: poth@lat-lon.de
033
034 Prof. Dr. Klaus Greve
035 Department of Geography
036 University of Bonn
037 Meckenheimer Allee 166
038 53115 Bonn
039 Germany
040 E-Mail: greve@giub.uni-bonn.de
041
042
043 ---------------------------------------------------------------------------*/
044 package org.deegree.io;
045
046 import java.sql.Connection;
047 import java.util.HashMap;
048 import java.util.Map;
049 import java.util.Properties;
050
051 /**
052 * class to manage a database connection pool. this is part of the combination of the object pool
053 * pattern an the singelton pattern.
054 *
055 * @author <a href="mailto:poth@lat-lon.de">Andreas Poth </a>
056 * @version 07.02.2001
057 */
058 public class DBConnectionPool {
059
060 private static DBConnectionPool instance = null;
061
062 private Map<String, DBPool> pools = null;
063
064 /**
065 * Creates a new DBConnectionPool object.
066 */
067 private DBConnectionPool() {
068 pools = new HashMap<String, DBPool>();
069 }
070
071 /**
072 * realize singelton pattern using double checked locking pattern.
073 *
074 * @return an instance of the data base pool. it is gauranteed that there exists only one
075 * instance of pool for each submitted class name.
076 *
077 */
078 public static DBConnectionPool getInstance() {
079 if ( instance == null ) {
080 synchronized ( DBConnectionPool.class ) {
081 if ( instance == null ) {
082 instance = new DBConnectionPool();
083 }
084 }
085 }
086
087 return instance;
088 }
089
090 /**
091 * get an object from the object pool
092 */
093 public synchronized Connection acquireConnection( final String driver, final String database, final String user,
094 final String password )
095 throws DBPoolException {
096 String q = driver + database + user + password;
097 DBPool pool = null;
098 if ( pools.get( q ) == null ) {
099 pool = new DBPool( driver, database, user, password );
100 pools.put( q, pool );
101 } else {
102 pool = pools.get( q );
103 }
104 return (Connection) pool.acquireObject();
105 }
106
107 /**
108 * get an object from the object pool
109 */
110 public synchronized Connection acquireConnection( final String driver, final String database,
111 final Properties properties )
112 throws DBPoolException {
113 String q = driver + database + properties.toString();
114
115 if ( pools.get( q ) == null ) {
116 DBPool pool = new DBPool( driver, database, properties );
117 pools.put( q, pool );
118 return (Connection) pool.acquireObject();
119 }
120 DBPool pool = pools.get( q );
121 return (Connection) pool.acquireObject();
122 }
123
124 /**
125 * releases a connection back to the pool
126 */
127 public synchronized void releaseConnection( final Connection con, final String driver, final String database,
128 final String user, final String password )
129 throws DBPoolException {
130 String q = driver + database + user + password;
131 DBPool pool = pools.get( q );
132 try {
133 pool.releaseObject( con );
134 } catch ( Exception e ) {
135 throw new DBPoolException( "could not release connection", e );
136 }
137 }
138
139 /**
140 * releases a connection back to the pool
141 */
142 public synchronized void releaseConnection( final Connection con, final String driver, final String database,
143 final Properties properties )
144 throws Exception {
145 String q = driver + database + properties.toString();
146 DBPool pool = pools.get( q );
147 pool.releaseObject( con );
148 }
149 }