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2 * Licensed to the Apache Software Foundation (ASF) under one *
3 * or more contributor license agreements. See the NOTICE file *
4 * distributed with this work for additional information *
5 * regarding copyright ownership. The ASF licenses this file *
6 * to you under the Apache License, Version 2.0 (the *
7 * "License"); you may not use this file except in compliance *
8 * with the License. You may obtain a copy of the License at *
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10 * http://www.apache.org/licenses/LICENSE-2.0 *
11 * *
12 * Unless required by applicable law or agreed to in writing, *
13 * software distributed under the License is distributed on an *
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY *
15 * KIND, either express or implied. See the License for the *
16 * specific language governing permissions and limitations *
17 * under the License. *
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19 package org.apache.james.postage.classloading;
20
21 import java.util.HashMap;
22 import java.util.Map;
23
24 import org.apache.commons.logging.Log;
25 import org.apache.commons.logging.LogFactory;
26
27 /***
28 * generic object factory, caching the class object for reuse
29 */
30 public class CachedInstanceFactory {
31
32 private static Log log = LogFactory.getLog(CachedInstanceFactory.class);
33
34 private final static Map m_classes = new HashMap();
35
36 public static Object createInstance(String classname) {
37 Object object = null;
38
39 Class clazz = null;
40
41 if (classname != null && m_classes.get(classname) == null) {
42 try {
43 clazz = Class.forName(classname);
44 } catch (ClassNotFoundException e) {
45 log.error("failed to load class " + classname, e);
46 }
47 }
48
49
50 if (clazz != null) {
51 try {
52 object = clazz.newInstance();
53 } catch (Exception e) {
54 log.error("failed to create instance of class " + classname, e);
55 }
56 }
57
58 return object;
59 }
60
61 }