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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, software<a name="line.12"></a>
<span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a>
<span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.util;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.io.IOException;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.nio.ByteBuffer;<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.Iterator;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.List;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.util.concurrent.ExecutorService;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import java.util.concurrent.Executors;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import java.util.concurrent.Future;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import java.util.function.BiConsumer;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.apache.hadoop.hbase.nio.ByteBuff;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import org.apache.hadoop.util.StringUtils;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.31"></a>
<span class="sourceLineNo">032</span>import org.slf4j.Logger;<a name="line.32"></a>
<span class="sourceLineNo">033</span>import org.slf4j.LoggerFactory;<a name="line.33"></a>
<span class="sourceLineNo">034</span><a name="line.34"></a>
<span class="sourceLineNo">035</span>/**<a name="line.35"></a>
<span class="sourceLineNo">036</span> * This class manages an array of ByteBuffers with a default size 4MB. These buffers are sequential<a name="line.36"></a>
<span class="sourceLineNo">037</span> * and could be considered as a large buffer.It supports reading/writing data from this large buffer<a name="line.37"></a>
<span class="sourceLineNo">038</span> * with a position and offset<a name="line.38"></a>
<span class="sourceLineNo">039</span> */<a name="line.39"></a>
<span class="sourceLineNo">040</span>@InterfaceAudience.Private<a name="line.40"></a>
<span class="sourceLineNo">041</span>public class ByteBufferArray {<a name="line.41"></a>
<span class="sourceLineNo">042</span> private static final Logger LOG = LoggerFactory.getLogger(ByteBufferArray.class);<a name="line.42"></a>
<span class="sourceLineNo">043</span><a name="line.43"></a>
<span class="sourceLineNo">044</span> public static final int DEFAULT_BUFFER_SIZE = 4 * 1024 * 1024;<a name="line.44"></a>
<span class="sourceLineNo">045</span> private final int bufferSize;<a name="line.45"></a>
<span class="sourceLineNo">046</span> private final int bufferCount;<a name="line.46"></a>
<span class="sourceLineNo">047</span> final ByteBuffer[] buffers;<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span> /**<a name="line.49"></a>
<span class="sourceLineNo">050</span> * We allocate a number of byte buffers as the capacity.<a name="line.50"></a>
<span class="sourceLineNo">051</span> * @param capacity total size of the byte buffer array<a name="line.51"></a>
<span class="sourceLineNo">052</span> * @param allocator the ByteBufferAllocator that will create the buffers<a name="line.52"></a>
<span class="sourceLineNo">053</span> * @throws IOException throws IOException if there is an exception thrown by the allocator<a name="line.53"></a>
<span class="sourceLineNo">054</span> */<a name="line.54"></a>
<span class="sourceLineNo">055</span> public ByteBufferArray(long capacity, ByteBufferAllocator allocator) throws IOException {<a name="line.55"></a>
<span class="sourceLineNo">056</span> this(getBufferSize(capacity), getBufferCount(capacity),<a name="line.56"></a>
<span class="sourceLineNo">057</span> Runtime.getRuntime().availableProcessors(), capacity, allocator);<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> ByteBufferArray(int bufferSize, int bufferCount, int threadCount, long capacity,<a name="line.60"></a>
<span class="sourceLineNo">061</span> ByteBufferAllocator alloc) throws IOException {<a name="line.61"></a>
<span class="sourceLineNo">062</span> this.bufferSize = bufferSize;<a name="line.62"></a>
<span class="sourceLineNo">063</span> this.bufferCount = bufferCount;<a name="line.63"></a>
<span class="sourceLineNo">064</span> LOG.info("Allocating buffers total={}, sizePerBuffer={}, count={}",<a name="line.64"></a>
<span class="sourceLineNo">065</span> StringUtils.byteDesc(capacity), StringUtils.byteDesc(bufferSize), bufferCount);<a name="line.65"></a>
<span class="sourceLineNo">066</span> this.buffers = new ByteBuffer[bufferCount];<a name="line.66"></a>
<span class="sourceLineNo">067</span> createBuffers(threadCount, alloc);<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> private void createBuffers(int threadCount, ByteBufferAllocator alloc) throws IOException {<a name="line.70"></a>
<span class="sourceLineNo">071</span> ExecutorService pool = Executors.newFixedThreadPool(threadCount);<a name="line.71"></a>
<span class="sourceLineNo">072</span> int perThreadCount = bufferCount / threadCount;<a name="line.72"></a>
<span class="sourceLineNo">073</span> int reminder = bufferCount % threadCount;<a name="line.73"></a>
<span class="sourceLineNo">074</span> try {<a name="line.74"></a>
<span class="sourceLineNo">075</span> List&lt;Future&lt;ByteBuffer[]&gt;&gt; futures = new ArrayList&lt;&gt;(threadCount);<a name="line.75"></a>
<span class="sourceLineNo">076</span> // Dispatch the creation task to each thread.<a name="line.76"></a>
<span class="sourceLineNo">077</span> for (int i = 0; i &lt; threadCount; i++) {<a name="line.77"></a>
<span class="sourceLineNo">078</span> final int chunkSize = perThreadCount + ((i == threadCount - 1) ? reminder : 0);<a name="line.78"></a>
<span class="sourceLineNo">079</span> futures.add(pool.submit(() -&gt; {<a name="line.79"></a>
<span class="sourceLineNo">080</span> ByteBuffer[] chunk = new ByteBuffer[chunkSize];<a name="line.80"></a>
<span class="sourceLineNo">081</span> for (int k = 0; k &lt; chunkSize; k++) {<a name="line.81"></a>
<span class="sourceLineNo">082</span> chunk[k] = alloc.allocate(bufferSize);<a name="line.82"></a>
<span class="sourceLineNo">083</span> }<a name="line.83"></a>
<span class="sourceLineNo">084</span> return chunk;<a name="line.84"></a>
<span class="sourceLineNo">085</span> }));<a name="line.85"></a>
<span class="sourceLineNo">086</span> }<a name="line.86"></a>
<span class="sourceLineNo">087</span> // Append the buffers created by each thread.<a name="line.87"></a>
<span class="sourceLineNo">088</span> int bufferIndex = 0;<a name="line.88"></a>
<span class="sourceLineNo">089</span> try {<a name="line.89"></a>
<span class="sourceLineNo">090</span> for (Future&lt;ByteBuffer[]&gt; f : futures) {<a name="line.90"></a>
<span class="sourceLineNo">091</span> for (ByteBuffer b : f.get()) {<a name="line.91"></a>
<span class="sourceLineNo">092</span> this.buffers[bufferIndex++] = b;<a name="line.92"></a>
<span class="sourceLineNo">093</span> }<a name="line.93"></a>
<span class="sourceLineNo">094</span> }<a name="line.94"></a>
<span class="sourceLineNo">095</span> assert bufferIndex == bufferCount;<a name="line.95"></a>
<span class="sourceLineNo">096</span> } catch (Exception e) {<a name="line.96"></a>
<span class="sourceLineNo">097</span> LOG.error("Buffer creation interrupted", e);<a name="line.97"></a>
<span class="sourceLineNo">098</span> throw new IOException(e);<a name="line.98"></a>
<span class="sourceLineNo">099</span> }<a name="line.99"></a>
<span class="sourceLineNo">100</span> } finally {<a name="line.100"></a>
<span class="sourceLineNo">101</span> pool.shutdownNow();<a name="line.101"></a>
<span class="sourceLineNo">102</span> }<a name="line.102"></a>
<span class="sourceLineNo">103</span> }<a name="line.103"></a>
<span class="sourceLineNo">104</span><a name="line.104"></a>
<span class="sourceLineNo">105</span> static int getBufferSize(long capacity) {<a name="line.105"></a>
<span class="sourceLineNo">106</span> int bufferSize = DEFAULT_BUFFER_SIZE;<a name="line.106"></a>
<span class="sourceLineNo">107</span> if (bufferSize &gt; (capacity / 16)) {<a name="line.107"></a>
<span class="sourceLineNo">108</span> bufferSize = (int) roundUp(capacity / 16, 32768);<a name="line.108"></a>
<span class="sourceLineNo">109</span> }<a name="line.109"></a>
<span class="sourceLineNo">110</span> return bufferSize;<a name="line.110"></a>
<span class="sourceLineNo">111</span> }<a name="line.111"></a>
<span class="sourceLineNo">112</span><a name="line.112"></a>
<span class="sourceLineNo">113</span> private static int getBufferCount(long capacity) {<a name="line.113"></a>
<span class="sourceLineNo">114</span> int bufferSize = getBufferSize(capacity);<a name="line.114"></a>
<span class="sourceLineNo">115</span> return (int) (roundUp(capacity, bufferSize) / bufferSize);<a name="line.115"></a>
<span class="sourceLineNo">116</span> }<a name="line.116"></a>
<span class="sourceLineNo">117</span><a name="line.117"></a>
<span class="sourceLineNo">118</span> private static long roundUp(long n, long to) {<a name="line.118"></a>
<span class="sourceLineNo">119</span> return ((n + to - 1) / to) * to;<a name="line.119"></a>
<span class="sourceLineNo">120</span> }<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> * Transfers bytes from this buffers array into the given destination {@link ByteBuff}<a name="line.123"></a>
<span class="sourceLineNo">124</span> * @param offset start position in this big logical array.<a name="line.124"></a>
<span class="sourceLineNo">125</span> * @param dst the destination ByteBuff. Notice that its position will be advanced.<a name="line.125"></a>
<span class="sourceLineNo">126</span> * @return number of bytes read<a name="line.126"></a>
<span class="sourceLineNo">127</span> */<a name="line.127"></a>
<span class="sourceLineNo">128</span> public int read(long offset, ByteBuff dst) {<a name="line.128"></a>
<span class="sourceLineNo">129</span> return internalTransfer(offset, dst, READER);<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> /**<a name="line.132"></a>
<span class="sourceLineNo">133</span> * Transfers bytes from the given source {@link ByteBuff} into this buffer array<a name="line.133"></a>
<span class="sourceLineNo">134</span> * @param offset start offset of this big logical array.<a name="line.134"></a>
<span class="sourceLineNo">135</span> * @param src the source ByteBuff. Notice that its position will be advanced.<a name="line.135"></a>
<span class="sourceLineNo">136</span> * @return number of bytes write<a name="line.136"></a>
<span class="sourceLineNo">137</span> */<a name="line.137"></a>
<span class="sourceLineNo">138</span> public int write(long offset, ByteBuff src) {<a name="line.138"></a>
<span class="sourceLineNo">139</span> return internalTransfer(offset, src, WRITER);<a name="line.139"></a>
<span class="sourceLineNo">140</span> }<a name="line.140"></a>
<span class="sourceLineNo">141</span><a name="line.141"></a>
<span class="sourceLineNo">142</span> /**<a name="line.142"></a>
<span class="sourceLineNo">143</span> * Transfer bytes from source {@link ByteBuff} to destination {@link ByteBuffer}. Position of both<a name="line.143"></a>
<span class="sourceLineNo">144</span> * source and destination will be advanced.<a name="line.144"></a>
<span class="sourceLineNo">145</span> */<a name="line.145"></a>
<span class="sourceLineNo">146</span> @SuppressWarnings("UnnecessaryLambda")<a name="line.146"></a>
<span class="sourceLineNo">147</span> private static final BiConsumer&lt;ByteBuffer, ByteBuff&gt; WRITER = (dst, src) -&gt; {<a name="line.147"></a>
<span class="sourceLineNo">148</span> int off = src.position(), len = dst.remaining();<a name="line.148"></a>
<span class="sourceLineNo">149</span> src.get(dst, off, len);<a name="line.149"></a>
<span class="sourceLineNo">150</span> src.position(off + len);<a name="line.150"></a>
<span class="sourceLineNo">151</span> };<a name="line.151"></a>
<span class="sourceLineNo">152</span><a name="line.152"></a>
<span class="sourceLineNo">153</span> /**<a name="line.153"></a>
<span class="sourceLineNo">154</span> * Transfer bytes from source {@link ByteBuffer} to destination {@link ByteBuff}, Position of both<a name="line.154"></a>
<span class="sourceLineNo">155</span> * source and destination will be advanced.<a name="line.155"></a>
<span class="sourceLineNo">156</span> */<a name="line.156"></a>
<span class="sourceLineNo">157</span> @SuppressWarnings("UnnecessaryLambda")<a name="line.157"></a>
<span class="sourceLineNo">158</span> private static final BiConsumer&lt;ByteBuffer, ByteBuff&gt; READER = (src, dst) -&gt; {<a name="line.158"></a>
<span class="sourceLineNo">159</span> int off = dst.position(), len = src.remaining(), srcOff = src.position();<a name="line.159"></a>
<span class="sourceLineNo">160</span> dst.put(off, ByteBuff.wrap(src), srcOff, len);<a name="line.160"></a>
<span class="sourceLineNo">161</span> src.position(srcOff + len);<a name="line.161"></a>
<span class="sourceLineNo">162</span> dst.position(off + len);<a name="line.162"></a>
<span class="sourceLineNo">163</span> };<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> * Transferring all remaining bytes from b to the buffers array starting at offset, or<a name="line.166"></a>
<span class="sourceLineNo">167</span> * transferring bytes from the buffers array at offset to b until b is filled. Notice that<a name="line.167"></a>
<span class="sourceLineNo">168</span> * position of ByteBuff b will be advanced.<a name="line.168"></a>
<span class="sourceLineNo">169</span> * @param offset where we start in the big logical array.<a name="line.169"></a>
<span class="sourceLineNo">170</span> * @param b the ByteBuff to transfer from or to<a name="line.170"></a>
<span class="sourceLineNo">171</span> * @param transfer the transfer interface.<a name="line.171"></a>
<span class="sourceLineNo">172</span> * @return the length of bytes we transferred.<a name="line.172"></a>
<span class="sourceLineNo">173</span> */<a name="line.173"></a>
<span class="sourceLineNo">174</span> private int internalTransfer(long offset, ByteBuff b, BiConsumer&lt;ByteBuffer, ByteBuff&gt; transfer) {<a name="line.174"></a>
<span class="sourceLineNo">175</span> int expectedTransferLen = b.remaining();<a name="line.175"></a>
<span class="sourceLineNo">176</span> if (expectedTransferLen == 0) {<a name="line.176"></a>
<span class="sourceLineNo">177</span> return 0;<a name="line.177"></a>
<span class="sourceLineNo">178</span> }<a name="line.178"></a>
<span class="sourceLineNo">179</span> BufferIterator it = new BufferIterator(offset, expectedTransferLen);<a name="line.179"></a>
<span class="sourceLineNo">180</span> while (it.hasNext()) {<a name="line.180"></a>
<span class="sourceLineNo">181</span> ByteBuffer a = it.next();<a name="line.181"></a>
<span class="sourceLineNo">182</span> transfer.accept(a, b);<a name="line.182"></a>
<span class="sourceLineNo">183</span> assert !a.hasRemaining();<a name="line.183"></a>
<span class="sourceLineNo">184</span> }<a name="line.184"></a>
<span class="sourceLineNo">185</span> assert expectedTransferLen == it.getSum() : "Expected transfer length (=" + expectedTransferLen<a name="line.185"></a>
<span class="sourceLineNo">186</span> + ") don't match the actual transfer length(=" + it.getSum() + ")";<a name="line.186"></a>
<span class="sourceLineNo">187</span> return expectedTransferLen;<a name="line.187"></a>
<span class="sourceLineNo">188</span> }<a name="line.188"></a>
<span class="sourceLineNo">189</span><a name="line.189"></a>
<span class="sourceLineNo">190</span> /**<a name="line.190"></a>
<span class="sourceLineNo">191</span> * Creates a sub-array from a given array of ByteBuffers from the given offset to the length<a name="line.191"></a>
<span class="sourceLineNo">192</span> * specified. For eg, if there are 4 buffers forming an array each with length 10 and if we call<a name="line.192"></a>
<span class="sourceLineNo">193</span> * asSubByteBuffers(5, 10) then we will create an sub-array consisting of two BBs and the first<a name="line.193"></a>
<span class="sourceLineNo">194</span> * one be a BB from 'position' 5 to a 'length' 5 and the 2nd BB will be from 'position' 0 to<a name="line.194"></a>
<span class="sourceLineNo">195</span> * 'length' 5.<a name="line.195"></a>
<span class="sourceLineNo">196</span> * @param offset the position in the whole array which is composited by multiple byte buffers.<a name="line.196"></a>
<span class="sourceLineNo">197</span> * @param len the length of bytes<a name="line.197"></a>
<span class="sourceLineNo">198</span> * @return the underlying ByteBuffers, each ByteBuffer is a slice from the backend and will have a<a name="line.198"></a>
<span class="sourceLineNo">199</span> * zero position.<a name="line.199"></a>
<span class="sourceLineNo">200</span> */<a name="line.200"></a>
<span class="sourceLineNo">201</span> public ByteBuffer[] asSubByteBuffers(long offset, final int len) {<a name="line.201"></a>
<span class="sourceLineNo">202</span> BufferIterator it = new BufferIterator(offset, len);<a name="line.202"></a>
<span class="sourceLineNo">203</span> ByteBuffer[] mbb = new ByteBuffer[it.getBufferCount()];<a name="line.203"></a>
<span class="sourceLineNo">204</span> for (int i = 0; i &lt; mbb.length; i++) {<a name="line.204"></a>
<span class="sourceLineNo">205</span> assert it.hasNext();<a name="line.205"></a>
<span class="sourceLineNo">206</span> mbb[i] = it.next();<a name="line.206"></a>
<span class="sourceLineNo">207</span> }<a name="line.207"></a>
<span class="sourceLineNo">208</span> assert it.getSum() == len;<a name="line.208"></a>
<span class="sourceLineNo">209</span> return mbb;<a name="line.209"></a>
<span class="sourceLineNo">210</span> }<a name="line.210"></a>
<span class="sourceLineNo">211</span><a name="line.211"></a>
<span class="sourceLineNo">212</span> /**<a name="line.212"></a>
<span class="sourceLineNo">213</span> * Iterator to fetch ByteBuffers from offset with given length in this big logical array.<a name="line.213"></a>
<span class="sourceLineNo">214</span> */<a name="line.214"></a>
<span class="sourceLineNo">215</span> private class BufferIterator implements Iterator&lt;ByteBuffer&gt; {<a name="line.215"></a>
<span class="sourceLineNo">216</span> private final int len;<a name="line.216"></a>
<span class="sourceLineNo">217</span> private int startBuffer, startOffset, endBuffer, endOffset;<a name="line.217"></a>
<span class="sourceLineNo">218</span> private int curIndex, sum = 0;<a name="line.218"></a>
<span class="sourceLineNo">219</span><a name="line.219"></a>
<span class="sourceLineNo">220</span> private int index(long pos) {<a name="line.220"></a>
<span class="sourceLineNo">221</span> return (int) (pos / bufferSize);<a name="line.221"></a>
<span class="sourceLineNo">222</span> }<a name="line.222"></a>
<span class="sourceLineNo">223</span><a name="line.223"></a>
<span class="sourceLineNo">224</span> private int offset(long pos) {<a name="line.224"></a>
<span class="sourceLineNo">225</span> return (int) (pos % bufferSize);<a name="line.225"></a>
<span class="sourceLineNo">226</span> }<a name="line.226"></a>
<span class="sourceLineNo">227</span><a name="line.227"></a>
<span class="sourceLineNo">228</span> public BufferIterator(long offset, int len) {<a name="line.228"></a>
<span class="sourceLineNo">229</span> assert len &gt;= 0 &amp;&amp; offset &gt;= 0;<a name="line.229"></a>
<span class="sourceLineNo">230</span> this.len = len;<a name="line.230"></a>
<span class="sourceLineNo">231</span><a name="line.231"></a>
<span class="sourceLineNo">232</span> this.startBuffer = index(offset);<a name="line.232"></a>
<span class="sourceLineNo">233</span> this.startOffset = offset(offset);<a name="line.233"></a>
<span class="sourceLineNo">234</span><a name="line.234"></a>
<span class="sourceLineNo">235</span> this.endBuffer = index(offset + len);<a name="line.235"></a>
<span class="sourceLineNo">236</span> this.endOffset = offset(offset + len);<a name="line.236"></a>
<span class="sourceLineNo">237</span> if (startBuffer &lt; endBuffer &amp;&amp; endOffset == 0) {<a name="line.237"></a>
<span class="sourceLineNo">238</span> endBuffer--;<a name="line.238"></a>
<span class="sourceLineNo">239</span> endOffset = bufferSize;<a name="line.239"></a>
<span class="sourceLineNo">240</span> }<a name="line.240"></a>
<span class="sourceLineNo">241</span> assert startBuffer &gt;= 0 &amp;&amp; startBuffer &lt; bufferCount;<a name="line.241"></a>
<span class="sourceLineNo">242</span> assert endBuffer &gt;= 0 &amp;&amp; endBuffer &lt; bufferCount;<a name="line.242"></a>
<span class="sourceLineNo">243</span><a name="line.243"></a>
<span class="sourceLineNo">244</span> // initialize the index to the first buffer index.<a name="line.244"></a>
<span class="sourceLineNo">245</span> this.curIndex = startBuffer;<a name="line.245"></a>
<span class="sourceLineNo">246</span> }<a name="line.246"></a>
<span class="sourceLineNo">247</span><a name="line.247"></a>
<span class="sourceLineNo">248</span> @Override<a name="line.248"></a>
<span class="sourceLineNo">249</span> public boolean hasNext() {<a name="line.249"></a>
<span class="sourceLineNo">250</span> return this.curIndex &lt;= endBuffer;<a name="line.250"></a>
<span class="sourceLineNo">251</span> }<a name="line.251"></a>
<span class="sourceLineNo">252</span><a name="line.252"></a>
<span class="sourceLineNo">253</span> /**<a name="line.253"></a>
<span class="sourceLineNo">254</span> * The returned ByteBuffer is an sliced one, it won't affect the position or limit of the<a name="line.254"></a>
<span class="sourceLineNo">255</span> * original one.<a name="line.255"></a>
<span class="sourceLineNo">256</span> */<a name="line.256"></a>
<span class="sourceLineNo">257</span> @Override<a name="line.257"></a>
<span class="sourceLineNo">258</span> public ByteBuffer next() {<a name="line.258"></a>
<span class="sourceLineNo">259</span> ByteBuffer bb = buffers[curIndex].duplicate();<a name="line.259"></a>
<span class="sourceLineNo">260</span> if (curIndex == startBuffer) {<a name="line.260"></a>
<span class="sourceLineNo">261</span> bb.position(startOffset).limit(Math.min(bufferSize, startOffset + len));<a name="line.261"></a>
<span class="sourceLineNo">262</span> } else if (curIndex == endBuffer) {<a name="line.262"></a>
<span class="sourceLineNo">263</span> bb.position(0).limit(endOffset);<a name="line.263"></a>
<span class="sourceLineNo">264</span> } else {<a name="line.264"></a>
<span class="sourceLineNo">265</span> bb.position(0).limit(bufferSize);<a name="line.265"></a>
<span class="sourceLineNo">266</span> }<a name="line.266"></a>
<span class="sourceLineNo">267</span> curIndex++;<a name="line.267"></a>
<span class="sourceLineNo">268</span> sum += bb.remaining();<a name="line.268"></a>
<span class="sourceLineNo">269</span> // Make sure that its pos is zero, it's important because MBB will count from zero for all nio<a name="line.269"></a>
<span class="sourceLineNo">270</span> // ByteBuffers.<a name="line.270"></a>
<span class="sourceLineNo">271</span> return bb.slice();<a name="line.271"></a>
<span class="sourceLineNo">272</span> }<a name="line.272"></a>
<span class="sourceLineNo">273</span><a name="line.273"></a>
<span class="sourceLineNo">274</span> int getSum() {<a name="line.274"></a>
<span class="sourceLineNo">275</span> return sum;<a name="line.275"></a>
<span class="sourceLineNo">276</span> }<a name="line.276"></a>
<span class="sourceLineNo">277</span><a name="line.277"></a>
<span class="sourceLineNo">278</span> int getBufferCount() {<a name="line.278"></a>
<span class="sourceLineNo">279</span> return this.endBuffer - this.startBuffer + 1;<a name="line.279"></a>
<span class="sourceLineNo">280</span> }<a name="line.280"></a>
<span class="sourceLineNo">281</span> }<a name="line.281"></a>
<span class="sourceLineNo">282</span>}<a name="line.282"></a>
</pre>
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