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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.handler.demux;
    21
    22  import org.apache.mina.core.session.IoSession;
    23
    24  /**
    25   * A handler interface that {@link DemuxingIoHandler} forwards
    26   * <code>exceptionCaught</code> events to.  You have to register your
    27   * handler with the type of exception you want to get notified using
    28   * {@link DemuxingIoHandler#addExceptionHandler(Class, ExceptionHandler)}.
    29   *
    30   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
    31   */
    32  public interface ExceptionHandler<E extends Throwable> {
    33      /**
    34       * A {@link ExceptionHandler} that does nothing.  This is useful when
    35       * you want to ignore an exception of a specific type silently.
    36       */
    37      static ExceptionHandler<Throwable> NOOP = new ExceptionHandler<Throwable>() {
    38          public void exceptionCaught(IoSession session, Throwable cause) {
    39              // Do nothing
    40          }
    41      };
    42
    43      /**
    44       * A {@link ExceptionHandler} that closes the session immediately.
    45       * This is useful when you want to close the session when an exception of
    46       * a specific type is raised.
    47       */
    48      static ExceptionHandler<Throwable> CLOSE = new ExceptionHandler<Throwable>() {
    49          public void exceptionCaught(IoSession session, Throwable cause) {
    50              session.close(true);
    51          }
    52      };
    53
    54      /**
    55       * Invoked when the specific type of exception is caught from the
    56       * specified <code>session</code>.
    57       */
    58      void exceptionCaught(IoSession session, E cause) throws Exception;
    59  }