001: //$HeadURL: https://svn.wald.intevation.org/svn/deegree/base/trunk/src/org/deegree/io/DBConnectionPool.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: 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: * @param driver
092: * driver to look for
093: * @param database
094: * the database to open
095: * @param user
096: * the username
097: * @param password
098: * the password.
099: * @return get a Connection from the Connection pool
100: * @throws DBPoolException
101: */
102: public synchronized Connection acquireConnection(
103: final String driver, final String database,
104: final String user, final String password)
105: throws DBPoolException {
106: String q = driver + database + user + password;
107: DBPool pool = null;
108: if (pools.get(q) == null) {
109: pool = new DBPool(driver, database, user, password);
110: pools.put(q, pool);
111: } else {
112: pool = pools.get(q);
113: }
114: return (Connection) pool.acquireObject();
115: }
116:
117: /**
118: * @param driver
119: * driver to look for
120: * @param database
121: * the database to open
122: * @param properties
123: * the properties of the database
124: * @return get a Connection from the Connection pool
125: * @throws DBPoolException
126: */
127: public synchronized Connection acquireConnection(
128: final String driver, final String database,
129: final Properties properties) throws DBPoolException {
130: String q = driver + database + properties.toString();
131:
132: if (pools.get(q) == null) {
133: DBPool pool = new DBPool(driver, database, properties);
134: pools.put(q, pool);
135: return (Connection) pool.acquireObject();
136: }
137: DBPool pool = pools.get(q);
138: return (Connection) pool.acquireObject();
139: }
140:
141: /**
142: * releases a connection back to the pool
143: *
144: * @param con
145: * connections to be released
146: * @param driver
147: * driver to look for
148: * @param database
149: * the database to open
150: * @param user
151: * the username
152: * @param password
153: * the password.
154: * @throws DBPoolException
155: */
156: public synchronized void releaseConnection(final Connection con,
157: final String driver, final String database,
158: final String user, final String password)
159: throws DBPoolException {
160: String q = driver + database + user + password;
161: DBPool pool = pools.get(q);
162: try {
163: pool.releaseObject(con);
164: } catch (Exception e) {
165: throw new DBPoolException("could not release connection", e);
166: }
167: }
168:
169: /**
170: * releases a connection back to the pool
171: *
172: * @param con
173: * connections to be released
174: * @param driver
175: * driver to look for
176: * @param database
177: * the database to open
178: * @param properties
179: * containing username and password.
180: * @throws Exception
181: */
182: public synchronized void releaseConnection(final Connection con,
183: final String driver, final String database,
184: final Properties properties) throws Exception {
185: String q = driver + database + properties.toString();
186: DBPool pool = pools.get(q);
187: pool.releaseObject(con);
188: }
189: }
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