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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.core.filterchain;
    21
    22  import org.apache.mina.core.session.IoSession;
    23
    24  /**
    25   * An interface that builds {@link IoFilterChain} in predefined way
    26   * when {@link IoSession} is created.  You can extract common filter chain
    27   * modification logic to this interface.  For example, to add a filter
    28   * to the chain,
    29   * <pre>
    30   * public class MyFilterChainBuilder implements IoFilterChainBuilder {
    31   *     public void buildFilterChain( IoFilterChain chain ) throws Exception {
    32   *         chain.addLast( "myFilter", new MyFilter() );
    33   *     }
    34   * }
    35   * </pre>
    36   *
    37   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
    38   */
    39  public interface IoFilterChainBuilder {
    40      /**
    41       * An implementation which does nothing.
    42       */
    43      IoFilterChainBuilder NOOP = new IoFilterChainBuilder() {
    44          public void buildFilterChain(IoFilterChain chain) throws Exception {
    45          }
    46
    47          @Override
    48          public String toString() {
    49              return "NOOP";
    50          }
    51      };
    52
    53      /**
    54       * Modifies the specified <tt>chain</tt>.
    55       */
    56      void buildFilterChain(IoFilterChain chain) throws Exception;
    57  }