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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.util;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span><a name="line.21"></a> |
| <span class="sourceLineNo">022</span>import java.io.Serializable;<a name="line.22"></a> |
| <span class="sourceLineNo">023</span>import java.util.AbstractList;<a name="line.23"></a> |
| <span class="sourceLineNo">024</span>import java.util.Arrays;<a name="line.24"></a> |
| <span class="sourceLineNo">025</span>import java.util.NoSuchElementException;<a name="line.25"></a> |
| <span class="sourceLineNo">026</span>import java.util.Queue;<a name="line.26"></a> |
| <span class="sourceLineNo">027</span><a name="line.27"></a> |
| <span class="sourceLineNo">028</span>/**<a name="line.28"></a> |
| <span class="sourceLineNo">029</span> * A unbounded circular queue based on array.<a name="line.29"></a> |
| <span class="sourceLineNo">030</span> * <a name="line.30"></a> |
| <span class="sourceLineNo">031</span> * @author <a href="http://mina.apache.org">Apache MINA Project</a><a name="line.31"></a> |
| <span class="sourceLineNo">032</span> */<a name="line.32"></a> |
| <span class="sourceLineNo">033</span>public class CircularQueue<E> extends AbstractList<E> implements Queue<E>, Serializable {<a name="line.33"></a> |
| <span class="sourceLineNo">034</span> /** The serialVersionUID : mandatory for serializable classes */<a name="line.34"></a> |
| <span class="sourceLineNo">035</span> private static final long serialVersionUID = 3993421269224511264L;<a name="line.35"></a> |
| <span class="sourceLineNo">036</span><a name="line.36"></a> |
| <span class="sourceLineNo">037</span> /** Minimal size of the underlying array */<a name="line.37"></a> |
| <span class="sourceLineNo">038</span> private static final int DEFAULT_CAPACITY = 4;<a name="line.38"></a> |
| <span class="sourceLineNo">039</span><a name="line.39"></a> |
| <span class="sourceLineNo">040</span> /** The initial capacity of the list */<a name="line.40"></a> |
| <span class="sourceLineNo">041</span> private final int initialCapacity;<a name="line.41"></a> |
| <span class="sourceLineNo">042</span><a name="line.42"></a> |
| <span class="sourceLineNo">043</span> // XXX: This volatile keyword here is a workaround for SUN Java Compiler bug,<a name="line.43"></a> |
| <span class="sourceLineNo">044</span> // which produces buggy byte code. I don't event know why adding a volatile<a name="line.44"></a> |
| <span class="sourceLineNo">045</span> // fixes the problem. Eclipse Java Compiler seems to produce correct byte code.<a name="line.45"></a> |
| <span class="sourceLineNo">046</span> private volatile Object[] items;<a name="line.46"></a> |
| <span class="sourceLineNo">047</span><a name="line.47"></a> |
| <span class="sourceLineNo">048</span> private int mask;<a name="line.48"></a> |
| <span class="sourceLineNo">049</span><a name="line.49"></a> |
| <span class="sourceLineNo">050</span> private int first = 0;<a name="line.50"></a> |
| <span class="sourceLineNo">051</span><a name="line.51"></a> |
| <span class="sourceLineNo">052</span> private int last = 0;<a name="line.52"></a> |
| <span class="sourceLineNo">053</span><a name="line.53"></a> |
| <span class="sourceLineNo">054</span> private boolean full;<a name="line.54"></a> |
| <span class="sourceLineNo">055</span><a name="line.55"></a> |
| <span class="sourceLineNo">056</span> private int shrinkThreshold;<a name="line.56"></a> |
| <span class="sourceLineNo">057</span><a name="line.57"></a> |
| <span class="sourceLineNo">058</span> /**<a name="line.58"></a> |
| <span class="sourceLineNo">059</span> * Construct a new, empty queue.<a name="line.59"></a> |
| <span class="sourceLineNo">060</span> */<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> public CircularQueue() {<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> this(DEFAULT_CAPACITY);<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> public CircularQueue(int initialCapacity) {<a name="line.65"></a> |
| <span class="sourceLineNo">066</span> int actualCapacity = normalizeCapacity(initialCapacity);<a name="line.66"></a> |
| <span class="sourceLineNo">067</span> items = new Object[actualCapacity];<a name="line.67"></a> |
| <span class="sourceLineNo">068</span> mask = actualCapacity - 1;<a name="line.68"></a> |
| <span class="sourceLineNo">069</span> this.initialCapacity = actualCapacity;<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> this.shrinkThreshold = 0;<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> }<a name="line.71"></a> |
| <span class="sourceLineNo">072</span><a name="line.72"></a> |
| <span class="sourceLineNo">073</span> /**<a name="line.73"></a> |
| <span class="sourceLineNo">074</span> * The capacity must be a power of 2.<a name="line.74"></a> |
| <span class="sourceLineNo">075</span> */<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> private static int normalizeCapacity(int initialCapacity) {<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> int actualCapacity = 1;<a name="line.77"></a> |
| <span class="sourceLineNo">078</span><a name="line.78"></a> |
| <span class="sourceLineNo">079</span> while (actualCapacity < initialCapacity) {<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> actualCapacity <<= 1;<a name="line.80"></a> |
| <span class="sourceLineNo">081</span> if (actualCapacity < 0) {<a name="line.81"></a> |
| <span class="sourceLineNo">082</span> actualCapacity = 1 << 30;<a name="line.82"></a> |
| <span class="sourceLineNo">083</span> break;<a name="line.83"></a> |
| <span class="sourceLineNo">084</span> }<a name="line.84"></a> |
| <span class="sourceLineNo">085</span> }<a name="line.85"></a> |
| <span class="sourceLineNo">086</span> return actualCapacity;<a name="line.86"></a> |
| <span class="sourceLineNo">087</span> }<a name="line.87"></a> |
| <span class="sourceLineNo">088</span><a name="line.88"></a> |
| <span class="sourceLineNo">089</span> /**<a name="line.89"></a> |
| <span class="sourceLineNo">090</span> * @return the capacity of this queue.<a name="line.90"></a> |
| <span class="sourceLineNo">091</span> */<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> public int capacity() {<a name="line.92"></a> |
| <span class="sourceLineNo">093</span> return items.length;<a name="line.93"></a> |
| <span class="sourceLineNo">094</span> }<a name="line.94"></a> |
| <span class="sourceLineNo">095</span><a name="line.95"></a> |
| <span class="sourceLineNo">096</span> @Override<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> public void clear() {<a name="line.97"></a> |
| <span class="sourceLineNo">098</span> if (!isEmpty()) {<a name="line.98"></a> |
| <span class="sourceLineNo">099</span> Arrays.fill(items, null);<a name="line.99"></a> |
| <span class="sourceLineNo">100</span> first = 0;<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> last = 0;<a name="line.101"></a> |
| <span class="sourceLineNo">102</span> full = false;<a name="line.102"></a> |
| <span class="sourceLineNo">103</span> shrinkIfNeeded();<a name="line.103"></a> |
| <span class="sourceLineNo">104</span> }<a name="line.104"></a> |
| <span class="sourceLineNo">105</span> }<a name="line.105"></a> |
| <span class="sourceLineNo">106</span><a name="line.106"></a> |
| <span class="sourceLineNo">107</span> @SuppressWarnings("unchecked")<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> public E poll() {<a name="line.108"></a> |
| <span class="sourceLineNo">109</span> if (isEmpty()) {<a name="line.109"></a> |
| <span class="sourceLineNo">110</span> return null;<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> Object ret = items[first];<a name="line.113"></a> |
| <span class="sourceLineNo">114</span> items[first] = null;<a name="line.114"></a> |
| <span class="sourceLineNo">115</span> decreaseSize();<a name="line.115"></a> |
| <span class="sourceLineNo">116</span><a name="line.116"></a> |
| <span class="sourceLineNo">117</span> if (first == last) {<a name="line.117"></a> |
| <span class="sourceLineNo">118</span> first = last = 0;<a name="line.118"></a> |
| <span class="sourceLineNo">119</span> }<a name="line.119"></a> |
| <span class="sourceLineNo">120</span><a name="line.120"></a> |
| <span class="sourceLineNo">121</span> shrinkIfNeeded();<a name="line.121"></a> |
| <span class="sourceLineNo">122</span> return (E) ret;<a name="line.122"></a> |
| <span class="sourceLineNo">123</span> }<a name="line.123"></a> |
| <span class="sourceLineNo">124</span><a name="line.124"></a> |
| <span class="sourceLineNo">125</span> public boolean offer(E item) {<a name="line.125"></a> |
| <span class="sourceLineNo">126</span> if (item == null) {<a name="line.126"></a> |
| <span class="sourceLineNo">127</span> throw new IllegalArgumentException("item");<a name="line.127"></a> |
| <span class="sourceLineNo">128</span> }<a name="line.128"></a> |
| <span class="sourceLineNo">129</span><a name="line.129"></a> |
| <span class="sourceLineNo">130</span> expandIfNeeded();<a name="line.130"></a> |
| <span class="sourceLineNo">131</span> items[last] = item;<a name="line.131"></a> |
| <span class="sourceLineNo">132</span> increaseSize();<a name="line.132"></a> |
| <span class="sourceLineNo">133</span> return true;<a name="line.133"></a> |
| <span class="sourceLineNo">134</span> }<a name="line.134"></a> |
| <span class="sourceLineNo">135</span><a name="line.135"></a> |
| <span class="sourceLineNo">136</span> @SuppressWarnings("unchecked")<a name="line.136"></a> |
| <span class="sourceLineNo">137</span> public E peek() {<a name="line.137"></a> |
| <span class="sourceLineNo">138</span> if (isEmpty()) {<a name="line.138"></a> |
| <span class="sourceLineNo">139</span> return null;<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> return (E) items[first];<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> @SuppressWarnings("unchecked")<a name="line.145"></a> |
| <span class="sourceLineNo">146</span> @Override<a name="line.146"></a> |
| <span class="sourceLineNo">147</span> public E get(int idx) {<a name="line.147"></a> |
| <span class="sourceLineNo">148</span> checkIndex(idx);<a name="line.148"></a> |
| <span class="sourceLineNo">149</span> return (E) items[getRealIndex(idx)];<a name="line.149"></a> |
| <span class="sourceLineNo">150</span> }<a name="line.150"></a> |
| <span class="sourceLineNo">151</span><a name="line.151"></a> |
| <span class="sourceLineNo">152</span> @Override<a name="line.152"></a> |
| <span class="sourceLineNo">153</span> public boolean isEmpty() {<a name="line.153"></a> |
| <span class="sourceLineNo">154</span> return (first == last) && !full;<a name="line.154"></a> |
| <span class="sourceLineNo">155</span> }<a name="line.155"></a> |
| <span class="sourceLineNo">156</span><a name="line.156"></a> |
| <span class="sourceLineNo">157</span> @Override<a name="line.157"></a> |
| <span class="sourceLineNo">158</span> public int size() {<a name="line.158"></a> |
| <span class="sourceLineNo">159</span> if (full) {<a name="line.159"></a> |
| <span class="sourceLineNo">160</span> return capacity();<a name="line.160"></a> |
| <span class="sourceLineNo">161</span> }<a name="line.161"></a> |
| <span class="sourceLineNo">162</span><a name="line.162"></a> |
| <span class="sourceLineNo">163</span> if (last >= first) {<a name="line.163"></a> |
| <span class="sourceLineNo">164</span> return last - first;<a name="line.164"></a> |
| <span class="sourceLineNo">165</span> }<a name="line.165"></a> |
| <span class="sourceLineNo">166</span><a name="line.166"></a> |
| <span class="sourceLineNo">167</span> return last - first + capacity();<a name="line.167"></a> |
| <span class="sourceLineNo">168</span> }<a name="line.168"></a> |
| <span class="sourceLineNo">169</span><a name="line.169"></a> |
| <span class="sourceLineNo">170</span> @Override<a name="line.170"></a> |
| <span class="sourceLineNo">171</span> public String toString() {<a name="line.171"></a> |
| <span class="sourceLineNo">172</span> return "first=" + first + ", last=" + last + ", size=" + size() + ", mask = " + mask;<a name="line.172"></a> |
| <span class="sourceLineNo">173</span> }<a name="line.173"></a> |
| <span class="sourceLineNo">174</span><a name="line.174"></a> |
| <span class="sourceLineNo">175</span> private void checkIndex(int idx) {<a name="line.175"></a> |
| <span class="sourceLineNo">176</span> if (idx < 0 || idx >= size()) {<a name="line.176"></a> |
| <span class="sourceLineNo">177</span> throw new IndexOutOfBoundsException(String.valueOf(idx));<a name="line.177"></a> |
| <span class="sourceLineNo">178</span> }<a name="line.178"></a> |
| <span class="sourceLineNo">179</span> }<a name="line.179"></a> |
| <span class="sourceLineNo">180</span><a name="line.180"></a> |
| <span class="sourceLineNo">181</span> private int getRealIndex(int idx) {<a name="line.181"></a> |
| <span class="sourceLineNo">182</span> return (first + idx) & mask;<a name="line.182"></a> |
| <span class="sourceLineNo">183</span> }<a name="line.183"></a> |
| <span class="sourceLineNo">184</span><a name="line.184"></a> |
| <span class="sourceLineNo">185</span> private void increaseSize() {<a name="line.185"></a> |
| <span class="sourceLineNo">186</span> last = (last + 1) & mask;<a name="line.186"></a> |
| <span class="sourceLineNo">187</span> full = first == last;<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> private void decreaseSize() {<a name="line.190"></a> |
| <span class="sourceLineNo">191</span> first = (first + 1) & mask;<a name="line.191"></a> |
| <span class="sourceLineNo">192</span> full = false;<a name="line.192"></a> |
| <span class="sourceLineNo">193</span> }<a name="line.193"></a> |
| <span class="sourceLineNo">194</span><a name="line.194"></a> |
| <span class="sourceLineNo">195</span> private void expandIfNeeded() {<a name="line.195"></a> |
| <span class="sourceLineNo">196</span> if (full) {<a name="line.196"></a> |
| <span class="sourceLineNo">197</span> // expand queue<a name="line.197"></a> |
| <span class="sourceLineNo">198</span> final int oldLen = items.length;<a name="line.198"></a> |
| <span class="sourceLineNo">199</span> final int newLen = oldLen << 1;<a name="line.199"></a> |
| <span class="sourceLineNo">200</span> Object[] tmp = new Object[newLen];<a name="line.200"></a> |
| <span class="sourceLineNo">201</span><a name="line.201"></a> |
| <span class="sourceLineNo">202</span> if (first < last) {<a name="line.202"></a> |
| <span class="sourceLineNo">203</span> System.arraycopy(items, first, tmp, 0, last - first);<a name="line.203"></a> |
| <span class="sourceLineNo">204</span> } else {<a name="line.204"></a> |
| <span class="sourceLineNo">205</span> System.arraycopy(items, first, tmp, 0, oldLen - first);<a name="line.205"></a> |
| <span class="sourceLineNo">206</span> System.arraycopy(items, 0, tmp, oldLen - first, last);<a name="line.206"></a> |
| <span class="sourceLineNo">207</span> }<a name="line.207"></a> |
| <span class="sourceLineNo">208</span><a name="line.208"></a> |
| <span class="sourceLineNo">209</span> first = 0;<a name="line.209"></a> |
| <span class="sourceLineNo">210</span> last = oldLen;<a name="line.210"></a> |
| <span class="sourceLineNo">211</span> items = tmp;<a name="line.211"></a> |
| <span class="sourceLineNo">212</span> mask = tmp.length - 1;<a name="line.212"></a> |
| <span class="sourceLineNo">213</span> if (newLen >>> 3 > initialCapacity) {<a name="line.213"></a> |
| <span class="sourceLineNo">214</span> shrinkThreshold = newLen >>> 3;<a name="line.214"></a> |
| <span class="sourceLineNo">215</span> }<a name="line.215"></a> |
| <span class="sourceLineNo">216</span> }<a name="line.216"></a> |
| <span class="sourceLineNo">217</span> }<a name="line.217"></a> |
| <span class="sourceLineNo">218</span><a name="line.218"></a> |
| <span class="sourceLineNo">219</span> private void shrinkIfNeeded() {<a name="line.219"></a> |
| <span class="sourceLineNo">220</span> int size = size();<a name="line.220"></a> |
| <span class="sourceLineNo">221</span> if (size <= shrinkThreshold) {<a name="line.221"></a> |
| <span class="sourceLineNo">222</span> // shrink queue<a name="line.222"></a> |
| <span class="sourceLineNo">223</span> final int oldLen = items.length;<a name="line.223"></a> |
| <span class="sourceLineNo">224</span> int newLen = normalizeCapacity(size);<a name="line.224"></a> |
| <span class="sourceLineNo">225</span> if (size == newLen) {<a name="line.225"></a> |
| <span class="sourceLineNo">226</span> newLen <<= 1;<a name="line.226"></a> |
| <span class="sourceLineNo">227</span> }<a name="line.227"></a> |
| <span class="sourceLineNo">228</span><a name="line.228"></a> |
| <span class="sourceLineNo">229</span> if (newLen >= oldLen) {<a name="line.229"></a> |
| <span class="sourceLineNo">230</span> return;<a name="line.230"></a> |
| <span class="sourceLineNo">231</span> }<a name="line.231"></a> |
| <span class="sourceLineNo">232</span><a name="line.232"></a> |
| <span class="sourceLineNo">233</span> if (newLen < initialCapacity) {<a name="line.233"></a> |
| <span class="sourceLineNo">234</span> if (oldLen == initialCapacity) {<a name="line.234"></a> |
| <span class="sourceLineNo">235</span> return;<a name="line.235"></a> |
| <span class="sourceLineNo">236</span> }<a name="line.236"></a> |
| <span class="sourceLineNo">237</span><a name="line.237"></a> |
| <span class="sourceLineNo">238</span> newLen = initialCapacity;<a name="line.238"></a> |
| <span class="sourceLineNo">239</span> }<a name="line.239"></a> |
| <span class="sourceLineNo">240</span><a name="line.240"></a> |
| <span class="sourceLineNo">241</span> Object[] tmp = new Object[newLen];<a name="line.241"></a> |
| <span class="sourceLineNo">242</span><a name="line.242"></a> |
| <span class="sourceLineNo">243</span> // Copy only when there's something to copy.<a name="line.243"></a> |
| <span class="sourceLineNo">244</span> if (size > 0) {<a name="line.244"></a> |
| <span class="sourceLineNo">245</span> if (first < last) {<a name="line.245"></a> |
| <span class="sourceLineNo">246</span> System.arraycopy(items, first, tmp, 0, last - first);<a name="line.246"></a> |
| <span class="sourceLineNo">247</span> } else {<a name="line.247"></a> |
| <span class="sourceLineNo">248</span> System.arraycopy(items, first, tmp, 0, oldLen - first);<a name="line.248"></a> |
| <span class="sourceLineNo">249</span> System.arraycopy(items, 0, tmp, oldLen - first, last);<a name="line.249"></a> |
| <span class="sourceLineNo">250</span> }<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> first = 0;<a name="line.253"></a> |
| <span class="sourceLineNo">254</span> last = size;<a name="line.254"></a> |
| <span class="sourceLineNo">255</span> items = tmp;<a name="line.255"></a> |
| <span class="sourceLineNo">256</span> mask = tmp.length - 1;<a name="line.256"></a> |
| <span class="sourceLineNo">257</span> shrinkThreshold = 0;<a name="line.257"></a> |
| <span class="sourceLineNo">258</span> }<a name="line.258"></a> |
| <span class="sourceLineNo">259</span> }<a name="line.259"></a> |
| <span class="sourceLineNo">260</span><a name="line.260"></a> |
| <span class="sourceLineNo">261</span> @Override<a name="line.261"></a> |
| <span class="sourceLineNo">262</span> public boolean add(E o) {<a name="line.262"></a> |
| <span class="sourceLineNo">263</span> return offer(o);<a name="line.263"></a> |
| <span class="sourceLineNo">264</span> }<a name="line.264"></a> |
| <span class="sourceLineNo">265</span><a name="line.265"></a> |
| <span class="sourceLineNo">266</span> @SuppressWarnings("unchecked")<a name="line.266"></a> |
| <span class="sourceLineNo">267</span> @Override<a name="line.267"></a> |
| <span class="sourceLineNo">268</span> public E set(int idx, E o) {<a name="line.268"></a> |
| <span class="sourceLineNo">269</span> checkIndex(idx);<a name="line.269"></a> |
| <span class="sourceLineNo">270</span><a name="line.270"></a> |
| <span class="sourceLineNo">271</span> int realIdx = getRealIndex(idx);<a name="line.271"></a> |
| <span class="sourceLineNo">272</span> Object old = items[realIdx];<a name="line.272"></a> |
| <span class="sourceLineNo">273</span> items[realIdx] = o;<a name="line.273"></a> |
| <span class="sourceLineNo">274</span> return (E) old;<a name="line.274"></a> |
| <span class="sourceLineNo">275</span> }<a name="line.275"></a> |
| <span class="sourceLineNo">276</span><a name="line.276"></a> |
| <span class="sourceLineNo">277</span> @Override<a name="line.277"></a> |
| <span class="sourceLineNo">278</span> public void add(int idx, E o) {<a name="line.278"></a> |
| <span class="sourceLineNo">279</span> if (idx == size()) {<a name="line.279"></a> |
| <span class="sourceLineNo">280</span> offer(o);<a name="line.280"></a> |
| <span class="sourceLineNo">281</span> return;<a name="line.281"></a> |
| <span class="sourceLineNo">282</span> }<a name="line.282"></a> |
| <span class="sourceLineNo">283</span><a name="line.283"></a> |
| <span class="sourceLineNo">284</span> checkIndex(idx);<a name="line.284"></a> |
| <span class="sourceLineNo">285</span> expandIfNeeded();<a name="line.285"></a> |
| <span class="sourceLineNo">286</span><a name="line.286"></a> |
| <span class="sourceLineNo">287</span> int realIdx = getRealIndex(idx);<a name="line.287"></a> |
| <span class="sourceLineNo">288</span><a name="line.288"></a> |
| <span class="sourceLineNo">289</span> // Make a room for a new element.<a name="line.289"></a> |
| <span class="sourceLineNo">290</span> if (first < last) {<a name="line.290"></a> |
| <span class="sourceLineNo">291</span> System.arraycopy(items, realIdx, items, realIdx + 1, last - realIdx);<a name="line.291"></a> |
| <span class="sourceLineNo">292</span> } else {<a name="line.292"></a> |
| <span class="sourceLineNo">293</span> if (realIdx >= first) {<a name="line.293"></a> |
| <span class="sourceLineNo">294</span> System.arraycopy(items, 0, items, 1, last);<a name="line.294"></a> |
| <span class="sourceLineNo">295</span> items[0] = items[items.length - 1];<a name="line.295"></a> |
| <span class="sourceLineNo">296</span> System.arraycopy(items, realIdx, items, realIdx + 1, items.length - realIdx - 1);<a name="line.296"></a> |
| <span class="sourceLineNo">297</span> } else {<a name="line.297"></a> |
| <span class="sourceLineNo">298</span> System.arraycopy(items, realIdx, items, realIdx + 1, last - realIdx);<a name="line.298"></a> |
| <span class="sourceLineNo">299</span> }<a name="line.299"></a> |
| <span class="sourceLineNo">300</span> }<a name="line.300"></a> |
| <span class="sourceLineNo">301</span><a name="line.301"></a> |
| <span class="sourceLineNo">302</span> items[realIdx] = o;<a name="line.302"></a> |
| <span class="sourceLineNo">303</span> increaseSize();<a name="line.303"></a> |
| <span class="sourceLineNo">304</span> }<a name="line.304"></a> |
| <span class="sourceLineNo">305</span><a name="line.305"></a> |
| <span class="sourceLineNo">306</span> @SuppressWarnings("unchecked")<a name="line.306"></a> |
| <span class="sourceLineNo">307</span> @Override<a name="line.307"></a> |
| <span class="sourceLineNo">308</span> public E remove(int idx) {<a name="line.308"></a> |
| <span class="sourceLineNo">309</span> if (idx == 0) {<a name="line.309"></a> |
| <span class="sourceLineNo">310</span> return poll();<a name="line.310"></a> |
| <span class="sourceLineNo">311</span> }<a name="line.311"></a> |
| <span class="sourceLineNo">312</span><a name="line.312"></a> |
| <span class="sourceLineNo">313</span> checkIndex(idx);<a name="line.313"></a> |
| <span class="sourceLineNo">314</span><a name="line.314"></a> |
| <span class="sourceLineNo">315</span> int realIdx = getRealIndex(idx);<a name="line.315"></a> |
| <span class="sourceLineNo">316</span> Object removed = items[realIdx];<a name="line.316"></a> |
| <span class="sourceLineNo">317</span><a name="line.317"></a> |
| <span class="sourceLineNo">318</span> // Remove a room for the removed element.<a name="line.318"></a> |
| <span class="sourceLineNo">319</span> if (first < last) {<a name="line.319"></a> |
| <span class="sourceLineNo">320</span> System.arraycopy(items, first, items, first + 1, realIdx - first);<a name="line.320"></a> |
| <span class="sourceLineNo">321</span> } else {<a name="line.321"></a> |
| <span class="sourceLineNo">322</span> if (realIdx >= first) {<a name="line.322"></a> |
| <span class="sourceLineNo">323</span> System.arraycopy(items, first, items, first + 1, realIdx - first);<a name="line.323"></a> |
| <span class="sourceLineNo">324</span> } else {<a name="line.324"></a> |
| <span class="sourceLineNo">325</span> System.arraycopy(items, 0, items, 1, realIdx);<a name="line.325"></a> |
| <span class="sourceLineNo">326</span> items[0] = items[items.length - 1];<a name="line.326"></a> |
| <span class="sourceLineNo">327</span> System.arraycopy(items, first, items, first + 1, items.length - first - 1);<a name="line.327"></a> |
| <span class="sourceLineNo">328</span> }<a name="line.328"></a> |
| <span class="sourceLineNo">329</span> }<a name="line.329"></a> |
| <span class="sourceLineNo">330</span><a name="line.330"></a> |
| <span class="sourceLineNo">331</span> items[first] = null;<a name="line.331"></a> |
| <span class="sourceLineNo">332</span> decreaseSize();<a name="line.332"></a> |
| <span class="sourceLineNo">333</span><a name="line.333"></a> |
| <span class="sourceLineNo">334</span> shrinkIfNeeded();<a name="line.334"></a> |
| <span class="sourceLineNo">335</span> return (E) removed;<a name="line.335"></a> |
| <span class="sourceLineNo">336</span> }<a name="line.336"></a> |
| <span class="sourceLineNo">337</span><a name="line.337"></a> |
| <span class="sourceLineNo">338</span> public E remove() {<a name="line.338"></a> |
| <span class="sourceLineNo">339</span> if (isEmpty()) {<a name="line.339"></a> |
| <span class="sourceLineNo">340</span> throw new NoSuchElementException();<a name="line.340"></a> |
| <span class="sourceLineNo">341</span> }<a name="line.341"></a> |
| <span class="sourceLineNo">342</span> return poll();<a name="line.342"></a> |
| <span class="sourceLineNo">343</span> }<a name="line.343"></a> |
| <span class="sourceLineNo">344</span><a name="line.344"></a> |
| <span class="sourceLineNo">345</span> public E element() {<a name="line.345"></a> |
| <span class="sourceLineNo">346</span> if (isEmpty()) {<a name="line.346"></a> |
| <span class="sourceLineNo">347</span> throw new NoSuchElementException();<a name="line.347"></a> |
| <span class="sourceLineNo">348</span> }<a name="line.348"></a> |
| <span class="sourceLineNo">349</span> return peek();<a name="line.349"></a> |
| <span class="sourceLineNo">350</span> }<a name="line.350"></a> |
| <span class="sourceLineNo">351</span>}<a name="line.351"></a> |
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| </pre> |
| </div> |
| </body> |
| </html> |
