001 //$HeadURL: svn+ssh://rbezema@svn.wald.intevation.org/deegree/base/tags/2.1/src/org/deegree/io/DBPool.java $
002 /*---------------- FILE HEADER ------------------------------------------
003
004 This file is part of deegree.
005 Copyright (C) 2001-2006 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: 6259 $
060 * @author <a href="mailto:poth@lat-lon.de">Andreas Poth</a>
061 * @author last edited by: $Author: bezema $
062 *
063 * @version 1.0. $Revision: 6259 $, $Date: 2007-03-20 10:15:15 +0100 (Di, 20 Mär 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,
084 final String password ) {
085
086 this.driver = driver;
087 this.database = database;
088 properties.put( "user", user );
089 properties.put( "password", password );
090 }
091
092 /**
093 * initialize pool for defined connection parameters
094 *
095 * @param driver
096 * @param database
097 * @param properties
098 */
099 public DBPool( final String driver, final String database, final Properties properties ) {
100
101 this.driver = driver;
102 this.database = database;
103 this.properties = properties;
104 }
105
106 /**
107 * get an object from the object pool
108 * @throws DBPoolException
109 */
110 public synchronized Object acquireObject() throws DBPoolException {
111 try {
112 // if the maximum amount of instances are in use
113 // wait until an instance has been released back
114 // to the pool or 20 seconds has passed
115 long timediff = 0;
116 while ( in_use.size() == getMaxInstances() && timediff < 20000 ) {
117 Thread.sleep( 100 );
118 timediff += 100;
119 }
120 // if no instance has been released within 20 seconds
121 // or can newly be instantiated return null
122 if ( timediff >= 20000 )
123 return null;
124
125 // if a none used is available from the pool
126 if ( available.size() > 0 ) {
127
128 // get/remove ojebct from the pool
129 Object o = available.remove( available.size() - 1 );
130 if ( ( (Connection) o ).isClosed() ) {
131 o = acquireObject();
132 }
133
134 // add it to 'in use' container
135 in_use.add( o );
136
137 // reset its start life time
138 startLifeTime.put( o, new Long( System.currentTimeMillis() ) );
139 // set the start of its usage
140 startUsageTime.put( o, new Long( System.currentTimeMillis() ) );
141
142 // return the object
143 return o;
144
145 }
146 // else instatiate a new object
147 // create a new class instance
148 DriverManager.registerDriver( (Driver) Class.forName( driver ).newInstance() );
149
150 Properties prop = (Properties) properties.clone();
151 Object connection = DriverManager.getConnection( database, prop );
152
153 existingInstances++;
154
155 // add it to 'in use' container
156 in_use.add( connection );
157 // set the start of its life time
158 startLifeTime.put( connection, new Long( System.currentTimeMillis() ) );
159 // set the start of its usage
160 startUsageTime.put( connection, new Long( System.currentTimeMillis() ) );
161 // return the object
162 return connection;
163 } catch ( Exception e ) {
164 e.printStackTrace();
165 throw new DBPoolException( "Error while acquiring connection: " + e.getMessage(), e );
166 }
167 }
168
169 /**
170 * will be called when the object is removed from the pool
171 * @param o
172 */
173 public void onObjectKill( Object o ) {
174 try {
175 ( (Connection) o ).close();
176 } catch ( SQLException e ) {
177 }
178 }
179
180 }
181 /* *********************************************************************************************
182 * Changes to this class. What the people have been up to:
183 * $Log$
184 * Revision 1.8 2007/01/06 13:45:17 poth
185 * code formating
186 * Revision 1.7
187 * 2006/07/12 14:46:18 poth comment footer added
188 *
189 **********************************************************************************************/