001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 * 019 */ 020package org.apache.mina.filter.codec; 021 022import org.apache.mina.core.buffer.IoBuffer; 023import org.apache.mina.core.session.IoSession; 024 025/** 026 * A {@link ProtocolDecoder} implementation which decorates an existing decoder 027 * to be thread-safe. Please be careful if you're going to use this decorator 028 * because it can be a root of performance degradation in a multi-thread 029 * environment. Also, by default, appropriate synchronization is done 030 * on a per-session basis by {@link ProtocolCodecFilter}. Please use this 031 * decorator only when you need to synchronize on a per-decoder basis, which 032 * is not common. 033 * 034 * @author <a href="http://mina.apache.org">Apache MINA Project</a> 035 */ 036public class SynchronizedProtocolDecoder implements ProtocolDecoder { 037 private final ProtocolDecoder decoder; 038 039 /** 040 * Creates a new instance which decorates the specified <tt>decoder</tt>. 041 * 042 * @param decoder The decorated decoder 043 */ 044 public SynchronizedProtocolDecoder(ProtocolDecoder decoder) { 045 if (decoder == null) { 046 throw new IllegalArgumentException("decoder"); 047 } 048 049 this.decoder = decoder; 050 } 051 052 /** 053 * @return the decoder this decoder is decorating. 054 */ 055 public ProtocolDecoder getDecoder() { 056 return decoder; 057 } 058 059 public void decode(IoSession session, IoBuffer in, ProtocolDecoderOutput out) throws Exception { 060 synchronized (decoder) { 061 decoder.decode(session, in, out); 062 } 063 } 064 065 /** 066 * {@inheritDoc} 067 */ 068 public void finishDecode(IoSession session, ProtocolDecoderOutput out) throws Exception { 069 synchronized (decoder) { 070 decoder.finishDecode(session, out); 071 } 072 } 073 074 /** 075 * {@inheritDoc} 076 */ 077 public void dispose(IoSession session) throws Exception { 078 synchronized (decoder) { 079 decoder.dispose(session); 080 } 081 } 082}