001 //$HeadURL: svn+ssh://rbezema@svn.wald.intevation.org/deegree/base/branches/2.2_testing/src/org/deegree/io/DBPool.java $
002 /*---------------- FILE HEADER ------------------------------------------
003
004 This file is part of deegree.
005 Copyright (C) 2001-2008 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
045 package org.deegree.io;
046
047 import java.sql.Connection;
048 import java.sql.Driver;
049 import java.sql.DriverManager;
050 import java.sql.SQLException;
051 import java.util.Properties;
052
053 import org.deegree.framework.util.ObjectPool;
054
055 /**
056 * class to manage a pool of database connections.
057 *
058 *
059 * @version $Revision: 9342 $
060 * @author <a href="mailto:poth@lat-lon.de">Andreas Poth</a>
061 * @author last edited by: $Author: apoth $
062 *
063 * @version 1.0. $Revision: 9342 $, $Date: 2007-12-27 13:32:57 +0100 (Do, 27 Dez 2007) $
064 *
065 * @since 2.0
066 */
067 public class DBPool extends ObjectPool {
068
069 private String driver = null;
070
071 private String database = null;
072
073 private Properties properties = new Properties();
074
075 /**
076 * initialize pool for defined connection parameters
077 *
078 * @param driver
079 * @param database
080 * @param user
081 * @param password
082 */
083 public DBPool( final String driver, final String database, final String user, final String password ) {
084
085 this.driver = driver;
086 this.database = database;
087 properties.put( "user", user );
088 properties.put( "password", password );
089 }
090
091 /**
092 * initialize pool for defined connection parameters
093 *
094 * @param driver
095 * @param database
096 * @param properties
097 */
098 public DBPool( final String driver, final String database, final Properties properties ) {
099
100 this.driver = driver;
101 this.database = database;
102 this.properties = properties;
103 }
104
105 /**
106 * get an object from the object pool
107 *
108 * @throws DBPoolException
109 */
110 public synchronized Object acquireObject()
111 throws DBPoolException {
112 try {
113 // if the maximum amount of instances are in use
114 // wait until an instance has been released back
115 // to the pool or 20 seconds has passed
116 long timediff = 0;
117 while ( in_use.size() == getMaxInstances() && timediff < 20000 ) {
118 Thread.sleep( 100 );
119 timediff += 100;
120 }
121 // if no instance has been released within 20 seconds
122 // or can newly be instantiated return null
123 if ( timediff >= 20000 )
124 return null;
125
126 // if a none used is available from the pool
127 if ( available.size() > 0 ) {
128
129 // get/remove ojebct from the pool
130 Object o = available.remove( available.size() - 1 );
131 if ( ( (Connection) o ).isClosed() ) {
132 o = acquireObject();
133 }
134
135 // add it to 'in use' container
136 in_use.add( o );
137
138 // reset its start life time
139 startLifeTime.put( o, new Long( System.currentTimeMillis() ) );
140 // set the start of its usage
141 startUsageTime.put( o, new Long( System.currentTimeMillis() ) );
142
143 // return the object
144 return o;
145
146 }
147 // else instatiate a new object
148 // create a new class instance
149 DriverManager.registerDriver( (Driver) Class.forName( driver ).newInstance() );
150
151 Properties prop = (Properties) properties.clone();
152 Object connection = DriverManager.getConnection( database, prop );
153
154 existingInstances++;
155
156 // add it to 'in use' container
157 in_use.add( connection );
158 // set the start of its life time
159 startLifeTime.put( connection, new Long( System.currentTimeMillis() ) );
160 // set the start of its usage
161 startUsageTime.put( connection, new Long( System.currentTimeMillis() ) );
162 // return the object
163 return connection;
164 } catch ( Exception e ) {
165 e.printStackTrace();
166 throw new DBPoolException( "Error while acquiring connection: " + e.getMessage(), e );
167 }
168 }
169
170 /**
171 * will be called when the object is removed from the pool
172 *
173 * @param o
174 */
175 public void onObjectKill( Object o ) {
176 try {
177 ( (Connection) o ).close();
178 } catch ( SQLException e ) {
179 }
180 }
181
182 }