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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  }