1 /***
2 * Copyright 2003-2010 Terracotta, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package net.sf.ehcache.util;
18
19 import java.lang.reflect.Constructor;
20 import java.lang.reflect.InvocationTargetException;
21
22 import net.sf.ehcache.CacheException;
23
24 /***
25 * Keeps all classloading in ehcache consistent.
26 *
27 * @author Greg Luck
28 * @version $Id: ClassLoaderUtil.html 13146 2011-08-01 17:12:39Z oletizi $
29 */
30 public final class ClassLoaderUtil {
31
32 /***
33 * Utility class.
34 */
35 private ClassLoaderUtil() {
36
37 }
38
39 /***
40 * Gets the <code>ClassLoader</code> that all classes in ehcache, and extensions, should
41 * use for classloading. All ClassLoading in ehcache should use this one. This is the only
42 * thing that seems to work for all of the class loading situations found in the wild.
43 * @return the thread context class loader.
44 */
45 public static ClassLoader getStandardClassLoader() {
46 return Thread.currentThread().getContextClassLoader();
47 }
48
49 /***
50 * Gets a fallback <code>ClassLoader</code> that all classes in ehcache, and extensions,
51 * should use for classloading. This is used if the context class loader does not work.
52 * @return the <code>ClassLoaderUtil.class.getClassLoader();</code>
53 */
54 public static ClassLoader getFallbackClassLoader() {
55 return ClassLoaderUtil.class.getClassLoader();
56 }
57
58 /***
59 * Creates a new class instance. Logs errors along the way. Classes are loaded using the
60 * ehcache standard classloader.
61 *
62 * @param className a fully qualified class name
63 * @return the newly created instance
64 * @throws CacheException if instance cannot be created due to a missing class or exception
65 */
66 public static Object createNewInstance(String className) throws CacheException {
67 return createNewInstance(className, new Class[0], new Object[0]);
68 }
69
70 /***
71 * Creates a new class instance and passes args to the constructor call. Logs errors along the way.
72 * Classes are loaded using the ehcache standard classloader.
73 *
74 * @param className a fully qualified class name
75 * @param argTypes Types for constructor argument parameters
76 * @param args Values for constructor argument parameters
77 * @return the newly created instance
78 * @throws CacheException if instance cannot be created due to a missing class or exception
79 */
80 public static Object createNewInstance(String className, Class[] argTypes, Object[] args) throws CacheException {
81 Class clazz;
82 Object newInstance;
83 try {
84 clazz = loadClass(className);
85 } catch (ClassNotFoundException e) {
86 throw new CacheException("Unable to load class " + className +
87 ". Initial cause was " + e.getMessage(), e);
88 }
89
90 try {
91 Constructor constructor = clazz.getConstructor(argTypes);
92 newInstance = constructor.newInstance(args);
93 } catch (IllegalAccessException e) {
94 throw new CacheException("Unable to load class " + className +
95 ". Initial cause was " + e.getMessage(), e);
96 } catch (InstantiationException e) {
97 throw new CacheException("Unable to load class " + className +
98 ". Initial cause was " + e.getMessage(), e);
99 } catch (NoSuchMethodException e) {
100 throw new CacheException("Unable to load class " + className +
101 ". Initial cause was " + e.getMessage(), e);
102 } catch (SecurityException e) {
103 throw new CacheException("Unable to load class " + className +
104 ". Initial cause was " + e.getMessage(), e);
105 } catch (IllegalArgumentException e) {
106 throw new CacheException("Unable to load class " + className +
107 ". Initial cause was " + e.getMessage(), e);
108 } catch (InvocationTargetException e) {
109 throw new CacheException("Unable to load class " + className +
110 ". Initial cause was " + e.getCause().getMessage(), e.getCause());
111 }
112 return newInstance;
113 }
114
115 /***
116 * Load the given class by name
117 *
118 * @param className a fully qualified class name
119 * @return Class the loaded class
120 * @throws ClassNotFoundException if the class cannot be loaded
121 * @since 1.7
122 */
123 public static Class loadClass(String className) throws ClassNotFoundException {
124 Class clazz;
125 try {
126 clazz = Class.forName(className, true, getStandardClassLoader());
127 } catch (ClassNotFoundException e) {
128
129 clazz = Class.forName(className, true, getFallbackClassLoader());
130 }
131
132 return clazz;
133 }
134
135
136
137 }