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| <pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a> |
| <span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a> |
| <span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a> |
| <span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a> |
| <span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a> |
| <span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a> |
| <span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a> |
| <span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a> |
| <span class="sourceLineNo">009</span> *<a name="line.9"></a> |
| <span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a> |
| <span class="sourceLineNo">011</span> *<a name="line.11"></a> |
| <span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing,<a name="line.12"></a> |
| <span class="sourceLineNo">013</span> * software distributed under the License is distributed on an<a name="line.13"></a> |
| <span class="sourceLineNo">014</span> * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY<a name="line.14"></a> |
| <span class="sourceLineNo">015</span> * KIND, either express or implied. See the License for the<a name="line.15"></a> |
| <span class="sourceLineNo">016</span> * specific language governing permissions and limitations<a name="line.16"></a> |
| <span class="sourceLineNo">017</span> * under the License.<a name="line.17"></a> |
| <span class="sourceLineNo">018</span> *<a name="line.18"></a> |
| <span class="sourceLineNo">019</span> */<a name="line.19"></a> |
| <span class="sourceLineNo">020</span>package org.apache.mina.filter.codec.statemachine;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span><a name="line.21"></a> |
| <span class="sourceLineNo">022</span>import java.util.ArrayList;<a name="line.22"></a> |
| <span class="sourceLineNo">023</span>import java.util.List;<a name="line.23"></a> |
| <span class="sourceLineNo">024</span><a name="line.24"></a> |
| <span class="sourceLineNo">025</span>import org.apache.mina.core.buffer.IoBuffer;<a name="line.25"></a> |
| <span class="sourceLineNo">026</span>import org.apache.mina.core.filterchain.IoFilter.NextFilter;<a name="line.26"></a> |
| <span class="sourceLineNo">027</span>import org.apache.mina.core.session.IoSession;<a name="line.27"></a> |
| <span class="sourceLineNo">028</span>import org.apache.mina.filter.codec.ProtocolCodecFilter;<a name="line.28"></a> |
| <span class="sourceLineNo">029</span>import org.apache.mina.filter.codec.ProtocolDecoderOutput;<a name="line.29"></a> |
| <span class="sourceLineNo">030</span>import org.slf4j.Logger;<a name="line.30"></a> |
| <span class="sourceLineNo">031</span>import org.slf4j.LoggerFactory;<a name="line.31"></a> |
| <span class="sourceLineNo">032</span><a name="line.32"></a> |
| <span class="sourceLineNo">033</span>/**<a name="line.33"></a> |
| <span class="sourceLineNo">034</span> * Abstract base class for decoder state machines. Calls {@link #init()} to<a name="line.34"></a> |
| <span class="sourceLineNo">035</span> * get the start {@link DecodingState} of the state machine. Calls <a name="line.35"></a> |
| <span class="sourceLineNo">036</span> * {@link #destroy()} when the state machine has reached its end state or when<a name="line.36"></a> |
| <span class="sourceLineNo">037</span> * the session is closed.<a name="line.37"></a> |
| <span class="sourceLineNo">038</span> * <p><a name="line.38"></a> |
| <span class="sourceLineNo">039</span> * NOTE: The {@link ProtocolDecoderOutput} used by this class when calling <a name="line.39"></a> |
| <span class="sourceLineNo">040</span> * {@link DecodingState#decode(IoBuffer, ProtocolDecoderOutput)} buffers decoded<a name="line.40"></a> |
| <span class="sourceLineNo">041</span> * messages in a {@link List}. Once the state machine has reached its end state<a name="line.41"></a> |
| <span class="sourceLineNo">042</span> * this class will call {@link #finishDecode(List, ProtocolDecoderOutput)}. The <a name="line.42"></a> |
| <span class="sourceLineNo">043</span> * implementation will have to take care of writing the decoded messages to the <a name="line.43"></a> |
| <span class="sourceLineNo">044</span> * real {@link ProtocolDecoderOutput} used by the configured <a name="line.44"></a> |
| <span class="sourceLineNo">045</span> * {@link ProtocolCodecFilter}.<a name="line.45"></a> |
| <span class="sourceLineNo">046</span> * </p><a name="line.46"></a> |
| <span class="sourceLineNo">047</span> * <a name="line.47"></a> |
| <span class="sourceLineNo">048</span> * @author <a href="http://mina.apache.org">Apache MINA Project</a><a name="line.48"></a> |
| <span class="sourceLineNo">049</span> */<a name="line.49"></a> |
| <span class="sourceLineNo">050</span>public abstract class DecodingStateMachine implements DecodingState {<a name="line.50"></a> |
| <span class="sourceLineNo">051</span> private final Logger log = LoggerFactory.getLogger(DecodingStateMachine.class);<a name="line.51"></a> |
| <span class="sourceLineNo">052</span><a name="line.52"></a> |
| <span class="sourceLineNo">053</span> private final List<Object> childProducts = new ArrayList<Object>();<a name="line.53"></a> |
| <span class="sourceLineNo">054</span><a name="line.54"></a> |
| <span class="sourceLineNo">055</span> private final ProtocolDecoderOutput childOutput = new ProtocolDecoderOutput() {<a name="line.55"></a> |
| <span class="sourceLineNo">056</span> public void flush(NextFilter nextFilter, IoSession session) {<a name="line.56"></a> |
| <span class="sourceLineNo">057</span> // Do nothing<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> }<a name="line.58"></a> |
| <span class="sourceLineNo">059</span><a name="line.59"></a> |
| <span class="sourceLineNo">060</span> public void write(Object message) {<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> childProducts.add(message);<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> }<a name="line.62"></a> |
| <span class="sourceLineNo">063</span> };<a name="line.63"></a> |
| <span class="sourceLineNo">064</span><a name="line.64"></a> |
| <span class="sourceLineNo">065</span> private DecodingState currentState;<a name="line.65"></a> |
| <span class="sourceLineNo">066</span><a name="line.66"></a> |
| <span class="sourceLineNo">067</span> private boolean initialized;<a name="line.67"></a> |
| <span class="sourceLineNo">068</span><a name="line.68"></a> |
| <span class="sourceLineNo">069</span> /**<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> * Invoked to initialize this state machine.<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> * <a name="line.71"></a> |
| <span class="sourceLineNo">072</span> * @return the start {@link DecodingState}.<a name="line.72"></a> |
| <span class="sourceLineNo">073</span> * @throws Exception if the initialization failed<a name="line.73"></a> |
| <span class="sourceLineNo">074</span> */<a name="line.74"></a> |
| <span class="sourceLineNo">075</span> protected abstract DecodingState init() throws Exception;<a name="line.75"></a> |
| <span class="sourceLineNo">076</span><a name="line.76"></a> |
| <span class="sourceLineNo">077</span> /**<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> * Called once the state machine has reached its end.<a name="line.78"></a> |
| <span class="sourceLineNo">079</span> * <a name="line.79"></a> |
| <span class="sourceLineNo">080</span> * @param childProducts contains the messages generated by each of the <a name="line.80"></a> |
| <span class="sourceLineNo">081</span> * {@link DecodingState}s which were exposed to the received data <a name="line.81"></a> |
| <span class="sourceLineNo">082</span> * during the life time of this state machine.<a name="line.82"></a> |
| <span class="sourceLineNo">083</span> * @param out the real {@link ProtocolDecoderOutput} used by the <a name="line.83"></a> |
| <span class="sourceLineNo">084</span> * {@link ProtocolCodecFilter}.<a name="line.84"></a> |
| <span class="sourceLineNo">085</span> * @return the next state if the state machine should resume.<a name="line.85"></a> |
| <span class="sourceLineNo">086</span> * @throws Exception if the decoding end failed<a name="line.86"></a> |
| <span class="sourceLineNo">087</span> */<a name="line.87"></a> |
| <span class="sourceLineNo">088</span> protected abstract DecodingState finishDecode(List<Object> childProducts, ProtocolDecoderOutput out)<a name="line.88"></a> |
| <span class="sourceLineNo">089</span> throws Exception;<a name="line.89"></a> |
| <span class="sourceLineNo">090</span><a name="line.90"></a> |
| <span class="sourceLineNo">091</span> /**<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> * Invoked to destroy this state machine once the end state has been reached<a name="line.92"></a> |
| <span class="sourceLineNo">093</span> * or the session has been closed.<a name="line.93"></a> |
| <span class="sourceLineNo">094</span> * <a name="line.94"></a> |
| <span class="sourceLineNo">095</span> * @throws Exception if the destruction failed<a name="line.95"></a> |
| <span class="sourceLineNo">096</span> */<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> protected abstract void destroy() throws Exception;<a name="line.97"></a> |
| <span class="sourceLineNo">098</span><a name="line.98"></a> |
| <span class="sourceLineNo">099</span> /**<a name="line.99"></a> |
| <span class="sourceLineNo">100</span> * {@inheritDoc}<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> */<a name="line.101"></a> |
| <span class="sourceLineNo">102</span> public DecodingState decode(IoBuffer in, ProtocolDecoderOutput out) throws Exception {<a name="line.102"></a> |
| <span class="sourceLineNo">103</span> DecodingState state = getCurrentState();<a name="line.103"></a> |
| <span class="sourceLineNo">104</span><a name="line.104"></a> |
| <span class="sourceLineNo">105</span> final int limit = in.limit();<a name="line.105"></a> |
| <span class="sourceLineNo">106</span> int pos = in.position();<a name="line.106"></a> |
| <span class="sourceLineNo">107</span><a name="line.107"></a> |
| <span class="sourceLineNo">108</span> try {<a name="line.108"></a> |
| <span class="sourceLineNo">109</span> for (;;) {<a name="line.109"></a> |
| <span class="sourceLineNo">110</span> // Wait for more data if all data is consumed.<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> if (pos == limit) {<a name="line.111"></a> |
| <span class="sourceLineNo">112</span> break;<a name="line.112"></a> |
| <span class="sourceLineNo">113</span> }<a name="line.113"></a> |
| <span class="sourceLineNo">114</span><a name="line.114"></a> |
| <span class="sourceLineNo">115</span> DecodingState oldState = state;<a name="line.115"></a> |
| <span class="sourceLineNo">116</span> state = state.decode(in, childOutput);<a name="line.116"></a> |
| <span class="sourceLineNo">117</span><a name="line.117"></a> |
| <span class="sourceLineNo">118</span> // If finished, call finishDecode<a name="line.118"></a> |
| <span class="sourceLineNo">119</span> if (state == null) {<a name="line.119"></a> |
| <span class="sourceLineNo">120</span> return finishDecode(childProducts, out);<a name="line.120"></a> |
| <span class="sourceLineNo">121</span> }<a name="line.121"></a> |
| <span class="sourceLineNo">122</span><a name="line.122"></a> |
| <span class="sourceLineNo">123</span> int newPos = in.position();<a name="line.123"></a> |
| <span class="sourceLineNo">124</span><a name="line.124"></a> |
| <span class="sourceLineNo">125</span> // Wait for more data if nothing is consumed and state didn't change.<a name="line.125"></a> |
| <span class="sourceLineNo">126</span> if (newPos == pos && oldState == state) {<a name="line.126"></a> |
| <span class="sourceLineNo">127</span> break;<a name="line.127"></a> |
| <span class="sourceLineNo">128</span> }<a name="line.128"></a> |
| <span class="sourceLineNo">129</span> pos = newPos;<a name="line.129"></a> |
| <span class="sourceLineNo">130</span> }<a name="line.130"></a> |
| <span class="sourceLineNo">131</span><a name="line.131"></a> |
| <span class="sourceLineNo">132</span> return this;<a name="line.132"></a> |
| <span class="sourceLineNo">133</span> } catch (Exception e) {<a name="line.133"></a> |
| <span class="sourceLineNo">134</span> state = null;<a name="line.134"></a> |
| <span class="sourceLineNo">135</span> throw e;<a name="line.135"></a> |
| <span class="sourceLineNo">136</span> } finally {<a name="line.136"></a> |
| <span class="sourceLineNo">137</span> this.currentState = state;<a name="line.137"></a> |
| <span class="sourceLineNo">138</span><a name="line.138"></a> |
| <span class="sourceLineNo">139</span> // Destroy if decoding is finished or failed.<a name="line.139"></a> |
| <span class="sourceLineNo">140</span> if (state == null) {<a name="line.140"></a> |
| <span class="sourceLineNo">141</span> cleanup();<a name="line.141"></a> |
| <span class="sourceLineNo">142</span> }<a name="line.142"></a> |
| <span class="sourceLineNo">143</span> }<a name="line.143"></a> |
| <span class="sourceLineNo">144</span> }<a name="line.144"></a> |
| <span class="sourceLineNo">145</span><a name="line.145"></a> |
| <span class="sourceLineNo">146</span> /**<a name="line.146"></a> |
| <span class="sourceLineNo">147</span> * {@inheritDoc}<a name="line.147"></a> |
| <span class="sourceLineNo">148</span> */<a name="line.148"></a> |
| <span class="sourceLineNo">149</span> public DecodingState finishDecode(ProtocolDecoderOutput out) throws Exception {<a name="line.149"></a> |
| <span class="sourceLineNo">150</span> DecodingState nextState;<a name="line.150"></a> |
| <span class="sourceLineNo">151</span> DecodingState state = getCurrentState();<a name="line.151"></a> |
| <span class="sourceLineNo">152</span> try {<a name="line.152"></a> |
| <span class="sourceLineNo">153</span> for (;;) {<a name="line.153"></a> |
| <span class="sourceLineNo">154</span> DecodingState oldState = state;<a name="line.154"></a> |
| <span class="sourceLineNo">155</span> state = state.finishDecode(childOutput);<a name="line.155"></a> |
| <span class="sourceLineNo">156</span> if (state == null) {<a name="line.156"></a> |
| <span class="sourceLineNo">157</span> // Finished<a name="line.157"></a> |
| <span class="sourceLineNo">158</span> break;<a name="line.158"></a> |
| <span class="sourceLineNo">159</span> }<a name="line.159"></a> |
| <span class="sourceLineNo">160</span><a name="line.160"></a> |
| <span class="sourceLineNo">161</span> // Exit if state didn't change.<a name="line.161"></a> |
| <span class="sourceLineNo">162</span> if (oldState == state) {<a name="line.162"></a> |
| <span class="sourceLineNo">163</span> break;<a name="line.163"></a> |
| <span class="sourceLineNo">164</span> }<a name="line.164"></a> |
| <span class="sourceLineNo">165</span> }<a name="line.165"></a> |
| <span class="sourceLineNo">166</span> } catch (Exception e) {<a name="line.166"></a> |
| <span class="sourceLineNo">167</span> state = null;<a name="line.167"></a> |
| <span class="sourceLineNo">168</span> log.debug("Ignoring the exception caused by a closed session.", e);<a name="line.168"></a> |
| <span class="sourceLineNo">169</span> } finally {<a name="line.169"></a> |
| <span class="sourceLineNo">170</span> this.currentState = state;<a name="line.170"></a> |
| <span class="sourceLineNo">171</span> nextState = finishDecode(childProducts, out);<a name="line.171"></a> |
| <span class="sourceLineNo">172</span> if (state == null) {<a name="line.172"></a> |
| <span class="sourceLineNo">173</span> cleanup();<a name="line.173"></a> |
| <span class="sourceLineNo">174</span> }<a name="line.174"></a> |
| <span class="sourceLineNo">175</span> }<a name="line.175"></a> |
| <span class="sourceLineNo">176</span> return nextState;<a name="line.176"></a> |
| <span class="sourceLineNo">177</span> }<a name="line.177"></a> |
| <span class="sourceLineNo">178</span><a name="line.178"></a> |
| <span class="sourceLineNo">179</span> private void cleanup() {<a name="line.179"></a> |
| <span class="sourceLineNo">180</span> if (!initialized) {<a name="line.180"></a> |
| <span class="sourceLineNo">181</span> throw new IllegalStateException();<a name="line.181"></a> |
| <span class="sourceLineNo">182</span> }<a name="line.182"></a> |
| <span class="sourceLineNo">183</span><a name="line.183"></a> |
| <span class="sourceLineNo">184</span> initialized = false;<a name="line.184"></a> |
| <span class="sourceLineNo">185</span> childProducts.clear();<a name="line.185"></a> |
| <span class="sourceLineNo">186</span> try {<a name="line.186"></a> |
| <span class="sourceLineNo">187</span> destroy();<a name="line.187"></a> |
| <span class="sourceLineNo">188</span> } catch (Exception e2) {<a name="line.188"></a> |
| <span class="sourceLineNo">189</span> log.warn("Failed to destroy a decoding state machine.", e2);<a name="line.189"></a> |
| <span class="sourceLineNo">190</span> }<a name="line.190"></a> |
| <span class="sourceLineNo">191</span> }<a name="line.191"></a> |
| <span class="sourceLineNo">192</span><a name="line.192"></a> |
| <span class="sourceLineNo">193</span> private DecodingState getCurrentState() throws Exception {<a name="line.193"></a> |
| <span class="sourceLineNo">194</span> DecodingState state = this.currentState;<a name="line.194"></a> |
| <span class="sourceLineNo">195</span> if (state == null) {<a name="line.195"></a> |
| <span class="sourceLineNo">196</span> state = init();<a name="line.196"></a> |
| <span class="sourceLineNo">197</span> initialized = true;<a name="line.197"></a> |
| <span class="sourceLineNo">198</span> }<a name="line.198"></a> |
| <span class="sourceLineNo">199</span> return state;<a name="line.199"></a> |
| <span class="sourceLineNo">200</span> }<a name="line.200"></a> |
| <span class="sourceLineNo">201</span>}<a name="line.201"></a> |
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