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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.util.Map;
19  
20  class CachingClassResolver implements ClassResolver {
21  
22      private final Map<String, Class<?>> classCache;
23      private final ClassResolver delegate;
24  
25      CachingClassResolver(ClassResolver delegate, Map<String, Class<?>> classCache) {
26          this.delegate = delegate;
27          this.classCache = classCache;
28      }
29  
30      public Class<?> resolve(String className) throws ClassNotFoundException {
31          // Query the cache first.
32          Class<?> clazz;
33          clazz = classCache.get(className);
34          if (clazz != null) {
35              return clazz;
36          }
37  
38          // And then try to load.
39          clazz = delegate.resolve(className);
40  
41          classCache.put(className, clazz);
42          return clazz;
43      }
44  
45  }