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 * https://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 io.netty.handler.codec.serialization;
17
18 import io.netty.util.internal.PlatformDependent;
19
20 import java.lang.ref.Reference;
21 import java.util.HashMap;
22 import java.util.concurrent.ConcurrentHashMap;
23
24 /**
25 * Factory methods for creating {@link ClassResolver} instances.
26 * <p>
27 * <strong>Security:</strong> serialization can be a security liability,
28 * and should not be used without defining a list of classes that are
29 * allowed to be desirialized. Such a list can be specified with the
30 * <tt>jdk.serialFilter</tt> system property, for instance.
31 * See the <a href="https://docs.oracle.com/en/java/javase/17/core/serialization-filtering1.html">
32 * serialization filtering</a> article for more information.
33 *
34 * @deprecated This class has been deprecated with no replacement,
35 * because serialization can be a security liability
36 */
37 @Deprecated
38 public final class ClassResolvers {
39
40 /**
41 * cache disabled
42 * @param classLoader - specific classLoader to use, or null if you want to revert to default
43 * @return new instance of class resolver
44 */
45 public static ClassResolver cacheDisabled(ClassLoader classLoader) {
46 return new ClassLoaderClassResolver(defaultClassLoader(classLoader));
47 }
48
49 /**
50 * non-aggressive non-concurrent cache
51 * good for non-shared default cache
52 *
53 * @param classLoader - specific classLoader to use, or null if you want to revert to default
54 * @return new instance of class resolver
55 */
56 public static ClassResolver weakCachingResolver(ClassLoader classLoader) {
57 return new CachingClassResolver(
58 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
59 new WeakReferenceMap<String, Class<?>>(new HashMap<String, Reference<Class<?>>>()));
60 }
61
62 /**
63 * aggressive non-concurrent cache
64 * good for non-shared cache, when we're not worried about class unloading
65 *
66 * @param classLoader - specific classLoader to use, or null if you want to revert to default
67 * @return new instance of class resolver
68 */
69 public static ClassResolver softCachingResolver(ClassLoader classLoader) {
70 return new CachingClassResolver(
71 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
72 new SoftReferenceMap<String, Class<?>>(new HashMap<String, Reference<Class<?>>>()));
73 }
74
75 /**
76 * non-aggressive concurrent cache
77 * good for shared cache, when we're worried about class unloading
78 *
79 * @param classLoader - specific classLoader to use, or null if you want to revert to default
80 * @return new instance of class resolver
81 */
82 public static ClassResolver weakCachingConcurrentResolver(ClassLoader classLoader) {
83 return new CachingClassResolver(
84 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
85 new WeakReferenceMap<String, Class<?>>(new ConcurrentHashMap<>()));
86 }
87
88 /**
89 * aggressive concurrent cache
90 * good for shared cache, when we're not worried about class unloading
91 *
92 * @param classLoader - specific classLoader to use, or null if you want to revert to default
93 * @return new instance of class resolver
94 */
95 public static ClassResolver softCachingConcurrentResolver(ClassLoader classLoader) {
96 return new CachingClassResolver(
97 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
98 new SoftReferenceMap<String, Class<?>>(new ConcurrentHashMap<>()));
99 }
100
101 static ClassLoader defaultClassLoader(ClassLoader classLoader) {
102 if (classLoader != null) {
103 return classLoader;
104 }
105
106 final ClassLoader contextClassLoader = PlatformDependent.getContextClassLoader();
107 if (contextClassLoader != null) {
108 return contextClassLoader;
109 }
110
111 return PlatformDependent.getClassLoader(ClassResolvers.class);
112 }
113
114 private ClassResolvers() {
115 // Unused
116 }
117 }