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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.marshalling;
17  
18  import org.jboss.marshalling.MarshallerFactory;
19  import org.jboss.marshalling.MarshallingConfiguration;
20  import org.jboss.marshalling.Unmarshaller;
21  import org.jboss.netty.channel.ChannelHandlerContext;
22  
23  /**
24   * {@link UnmarshallerProvider} implementation which use a {@link ThreadLocal} to store references
25   * to {@link Unmarshaller} instances. This may give you some performance boost if you need to unmarshall
26   * many small {@link Object}'s.
27   *
28   *
29   */
30  public class ThreadLocalUnmarshallerProvider implements UnmarshallerProvider {
31      private final ThreadLocal<Unmarshaller> unmarshallers = new ThreadLocal<Unmarshaller>();
32  
33      private final MarshallerFactory factory;
34      private final MarshallingConfiguration config;
35  
36      /**
37       * Create a new instance of the {@link ThreadLocalUnmarshallerProvider}
38       *
39       * @param factory   the {@link MarshallerFactory} to use to create {@link Unmarshaller}'s if needed
40       * @param config    the {@link MarshallingConfiguration} to use
41       */
42      public ThreadLocalUnmarshallerProvider(MarshallerFactory factory, MarshallingConfiguration config) {
43          this.factory = factory;
44          this.config = config;
45      }
46  
47      public Unmarshaller getUnmarshaller(ChannelHandlerContext ctx) throws Exception {
48          Unmarshaller unmarshaller = unmarshallers.get();
49          if (unmarshaller == null) {
50              unmarshaller = factory.createUnmarshaller(config);
51              unmarshallers.set(unmarshaller);
52          }
53          return unmarshaller;
54      }
55  
56  }