1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. 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, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 package org.jboss.netty.handler.codec.serialization;
17
18 import java.lang.ref.Reference;
19 import java.util.HashMap;
20 import java.util.concurrent.ConcurrentHashMap;
21
22 public final class ClassResolvers {
23
24 /**
25 * cache disabled
26 * @param classLoader - specific classLoader to use, or null if you want to revert to default
27 * @return new instance of class resolver
28 */
29 public static ClassResolver cacheDisabled(ClassLoader classLoader) {
30 return new ClassLoaderClassResolver(defaultClassLoader(classLoader));
31 }
32
33 /**
34 * non-agressive non-concurrent cache
35 * good for non-shared default cache
36 *
37 * @param classLoader - specific classLoader to use, or null if you want to revert to default
38 * @return new instance of class resolver
39 */
40 public static ClassResolver weakCachingResolver(ClassLoader classLoader) {
41 return new CachingClassResolver(
42 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
43 new WeakReferenceMap<String, Class<?>>(new HashMap<String, Reference<Class<?>>>()));
44 }
45
46 /**
47 * agressive non-concurrent cache
48 * good for non-shared cache, when we're not worried about class unloading
49 *
50 * @param classLoader - specific classLoader to use, or null if you want to revert to default
51 * @return new instance of class resolver
52 */
53 public static ClassResolver softCachingResolver(ClassLoader classLoader) {
54 return new CachingClassResolver(
55 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
56 new SoftReferenceMap<String, Class<?>>(new HashMap<String, Reference<Class<?>>>()));
57 }
58
59 /**
60 * non-agressive concurrent cache
61 * good for shared cache, when we're worried about class unloading
62 *
63 * @param classLoader - specific classLoader to use, or null if you want to revert to default
64 * @return new instance of class resolver
65 */
66 public static ClassResolver weakCachingConcurrentResolver(ClassLoader classLoader) {
67 return new CachingClassResolver(
68 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
69 new WeakReferenceMap<String, Class<?>>(new ConcurrentHashMap<String, Reference<Class<?>>>()));
70 }
71
72 /**
73 * agressive concurrent cache
74 * good for shared cache, when we're not worried about class unloading
75 *
76 * @param classLoader - specific classLoader to use, or null if you want to revert to default
77 * @return new instance of class resolver
78 */
79 public static ClassResolver softCachingConcurrentResolver(ClassLoader classLoader) {
80 return new CachingClassResolver(
81 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
82 new SoftReferenceMap<String, Class<?>>(new ConcurrentHashMap<String, Reference<Class<?>>>()));
83 }
84
85 static ClassLoader defaultClassLoader(ClassLoader classLoader) {
86 if (classLoader != null) {
87 return classLoader;
88 }
89
90 final ClassLoader contextClassLoader = Thread.currentThread().getContextClassLoader();
91 if (contextClassLoader != null) {
92 return contextClassLoader;
93 }
94
95 return ClassResolvers.class.getClassLoader();
96 }
97
98 private ClassResolvers() {
99 // Unused
100 }
101 }