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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License.
18   *
19   */
20  package org.apache.mina.common;
21  
22  /**
23   * An interface that builds {@link IoFilterChain} in predefined way
24   * when {@link IoSession} is created.  You can extract common filter chain
25   * modification logic to this interface.  For example, to add a filter
26   * to the chain,
27   * <pre>
28   * public class MyFilterChainBuilder implements IoFilterChainBuilder {
29   *     public void buildFilterChain( IoFilterChain chain ) throws Exception {
30   *         chain.addLast( "myFilter", new MyFilter() );
31   *     }
32   * }
33   * </pre>
34   *
35   * @author The Apache MINA Project (dev@mina.apache.org)
36   * @version $Rev: 576217 $, $Date: 2007-09-16 17:55:27 -0600 (Sun, 16 Sep 2007) $
37   */
38  public interface IoFilterChainBuilder {
39      /**
40       * An implementation which does nothing.
41       */
42      IoFilterChainBuilder NOOP = new IoFilterChainBuilder() {
43          public void buildFilterChain(IoFilterChain chain) throws Exception {
44          }
45  
46          @Override
47          public String toString() {
48              return "NOOP";
49          }
50      };
51  
52      /**
53       * Modifies the specified <tt>chain</tt>.
54       */
55      void buildFilterChain(IoFilterChain chain) throws Exception;
56  }