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
23 /**
24 * Factory methods for creating {@link ClassResolver} instances.
25 * <p>
26 * <strong>Security:</strong> serialization can be a security liability,
27 * and should not be used without defining a list of classes that are
28 * allowed to be desirialized. Such a list can be specified with the
29 * <tt>jdk.serialFilter</tt> system property, for instance.
30 * See the <a href="https://docs.oracle.com/en/java/javase/17/core/serialization-filtering1.html">
31 * serialization filtering</a> article for more information.
32 *
33 * @deprecated This class has been deprecated with no replacement,
34 * because serialization can be a security liability
35 */
36 @Deprecated
37 public final class ClassResolvers {
38
39 /**
40 * cache disabled
41 * @param classLoader - specific classLoader to use, or null if you want to revert to default
42 * @return new instance of class resolver
43 */
44 public static ClassResolver cacheDisabled(ClassLoader classLoader) {
45 return new ClassLoaderClassResolver(defaultClassLoader(classLoader));
46 }
47
48 /**
49 * non-aggressive non-concurrent cache
50 * good for non-shared default cache
51 *
52 * @param classLoader - specific classLoader to use, or null if you want to revert to default
53 * @return new instance of class resolver
54 */
55 public static ClassResolver weakCachingResolver(ClassLoader classLoader) {
56 return new CachingClassResolver(
57 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
58 new WeakReferenceMap<String, Class<?>>(new HashMap<String, Reference<Class<?>>>()));
59 }
60
61 /**
62 * aggressive non-concurrent cache
63 * good for non-shared cache, when we're not worried about class unloading
64 *
65 * @param classLoader - specific classLoader to use, or null if you want to revert to default
66 * @return new instance of class resolver
67 */
68 public static ClassResolver softCachingResolver(ClassLoader classLoader) {
69 return new CachingClassResolver(
70 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
71 new SoftReferenceMap<String, Class<?>>(new HashMap<String, Reference<Class<?>>>()));
72 }
73
74 /**
75 * non-aggressive concurrent cache
76 * good for shared cache, when we're worried about class unloading
77 *
78 * @param classLoader - specific classLoader to use, or null if you want to revert to default
79 * @return new instance of class resolver
80 */
81 public static ClassResolver weakCachingConcurrentResolver(ClassLoader classLoader) {
82 return new CachingClassResolver(
83 new ClassLoaderClassResolver(defaultClassLoader(classLoader)),
84 new WeakReferenceMap<String, Class<?>>(
85 PlatformDependent.<String, Reference<Class<?>>>newConcurrentHashMap()));
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<?>>(
99 PlatformDependent.<String, Reference<Class<?>>>newConcurrentHashMap()));
100 }
101
102 static ClassLoader defaultClassLoader(ClassLoader classLoader) {
103 if (classLoader != null) {
104 return classLoader;
105 }
106
107 final ClassLoader contextClassLoader = PlatformDependent.getContextClassLoader();
108 if (contextClassLoader != null) {
109 return contextClassLoader;
110 }
111
112 return PlatformDependent.getClassLoader(ClassResolvers.class);
113 }
114
115 private ClassResolvers() {
116 // Unused
117 }
118 }