01: /*
02: * ====================================================================
03: * JAFFA - Java Application Framework For All
04: *
05: * Copyright (C) 2002 JAFFA Development Group
06: *
07: * This library is free software; you can redistribute it and/or
08: * modify it under the terms of the GNU Lesser General Public
09: * License as published by the Free Software Foundation; either
10: * version 2.1 of the License, or (at your option) any later version.
11: *
12: * This library is distributed in the hope that it will be useful,
13: * but WITHOUT ANY WARRANTY; without even the implied warranty of
14: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15: * Lesser General Public License for more details.
16: *
17: * You should have received a copy of the GNU Lesser General Public
18: * License along with this library; if not, write to the Free Software
19: * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20: *
21: * Redistribution and use of this software and associated documentation ("Software"),
22: * with or without modification, are permitted provided that the following conditions are met:
23: * 1. Redistributions of source code must retain copyright statements and notices.
24: * Redistributions must also contain a copy of this document.
25: * 2. Redistributions in binary form must reproduce the above copyright notice,
26: * this list of conditions and the following disclaimer in the documentation
27: * and/or other materials provided with the distribution.
28: * 3. The name "JAFFA" must not be used to endorse or promote products derived from
29: * this Software without prior written permission. For written permission,
30: * please contact mail to: jaffagroup@yahoo.com.
31: * 4. Products derived from this Software may not be called "JAFFA" nor may "JAFFA"
32: * appear in their names without prior written permission.
33: * 5. Due credit should be given to the JAFFA Project (http://jaffa.sourceforge.net).
34: *
35: * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESSED OR IMPLIED
36: * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
37: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
38: * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
39: * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40: * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
41: * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
42: * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
43: * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
44: * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
45: * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
46: * SUCH DAMAGE.
47: * ====================================================================
48: */
49:
50: package org.jaffa.persistence.engines;
51:
52: import org.apache.log4j.Logger;
53: import java.util.HashMap;
54: import org.jaffa.config.Config;
55: import org.jaffa.persistence.exceptions.EngineInstantiationException;
56:
57: /** A factory class that returns an instance of a Persistence Engine. */
58: public class PersistenceEngineFactory {
59: private static final Logger log = Logger
60: .getLogger(PersistenceEngineFactory.class);
61: private static final String ENGINE_KEY = "framework.persistence.Persistence_Engine";
62:
63: /** Returns an instance of IPersistenceEngine.
64: * It reads the 'framework.persistence.Persistence_Engine' property from the framework.properties file.
65: * It then instantiates the class returned by the property.
66: * @return an instance of IPersistenceEngine.
67: * @throws EngineInstantiationException if the property is not defined, or if the class cannot be found, or if the class canot be instantiated.
68: */
69: public static IPersistenceEngine newInstance()
70: throws EngineInstantiationException {
71: String engineName = null;
72: try {
73: engineName = (String) Config.getProperty(ENGINE_KEY);
74: if (log.isDebugEnabled())
75: log
76: .debug("Creating an instance of the Persistence Engine: "
77: + engineName);
78: Class engineClass = Class.forName(engineName);
79: return (IPersistenceEngine) engineClass.newInstance();
80: } catch (Exception e) {
81: String str = "The Persistence Engine '" + engineName
82: + "' could not be instantiated";
83: log.error(str, e);
84: throw new EngineInstantiationException(null, e);
85: }
86: }
87: }
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