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<pre><span class="sourceLineNo">001</span>/* Cobertura - http://cobertura.sourceforge.net/<a name="line.1"></a>
<span class="sourceLineNo">002</span> *<a name="line.2"></a>
<span class="sourceLineNo">003</span> * Copyright (C) 2006 John Lewis<a name="line.3"></a>
<span class="sourceLineNo">004</span> * Copyright (C) 2006 Mark Doliner<a name="line.4"></a>
<span class="sourceLineNo">005</span> * Copyright (C) 2009 Chris van Es<a name="line.5"></a>
<span class="sourceLineNo">006</span> *<a name="line.6"></a>
<span class="sourceLineNo">007</span> * Note: This file is dual licensed under the GPL and the Apache<a name="line.7"></a>
<span class="sourceLineNo">008</span> * Source License 1.1 (so that it can be used from both the main<a name="line.8"></a>
<span class="sourceLineNo">009</span> * Cobertura classes and the ant tasks).<a name="line.9"></a>
<span class="sourceLineNo">010</span> *<a name="line.10"></a>
<span class="sourceLineNo">011</span> * Cobertura is free software; you can redistribute it and/or modify<a name="line.11"></a>
<span class="sourceLineNo">012</span> * it under the terms of the GNU General Public License as published<a name="line.12"></a>
<span class="sourceLineNo">013</span> * by the Free Software Foundation; either version 2 of the License,<a name="line.13"></a>
<span class="sourceLineNo">014</span> * or (at your option) any later version.<a name="line.14"></a>
<span class="sourceLineNo">015</span> *<a name="line.15"></a>
<span class="sourceLineNo">016</span> * Cobertura is distributed in the hope that it will be useful, but<a name="line.16"></a>
<span class="sourceLineNo">017</span> * WITHOUT ANY WARRANTY; without even the implied warranty of<a name="line.17"></a>
<span class="sourceLineNo">018</span> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU<a name="line.18"></a>
<span class="sourceLineNo">019</span> * General Public License for more details.<a name="line.19"></a>
<span class="sourceLineNo">020</span> *<a name="line.20"></a>
<span class="sourceLineNo">021</span> * You should have received a copy of the GNU General Public License<a name="line.21"></a>
<span class="sourceLineNo">022</span> * along with Cobertura; if not, write to the Free Software<a name="line.22"></a>
<span class="sourceLineNo">023</span> * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307<a name="line.23"></a>
<span class="sourceLineNo">024</span> * USA<a name="line.24"></a>
<span class="sourceLineNo">025</span> */<a name="line.25"></a>
<span class="sourceLineNo">026</span><a name="line.26"></a>
<span class="sourceLineNo">027</span>package net.sourceforge.cobertura.util;<a name="line.27"></a>
<span class="sourceLineNo">028</span><a name="line.28"></a>
<span class="sourceLineNo">029</span>import java.io.File;<a name="line.29"></a>
<span class="sourceLineNo">030</span>import java.io.FileNotFoundException;<a name="line.30"></a>
<span class="sourceLineNo">031</span>import java.io.RandomAccessFile;<a name="line.31"></a>
<span class="sourceLineNo">032</span>import java.lang.reflect.InvocationTargetException;<a name="line.32"></a>
<span class="sourceLineNo">033</span>import java.lang.reflect.Method;<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 controls access to any file so that multiple JVMs will<a name="line.36"></a>
<span class="sourceLineNo">037</span> * not be able to write to the file at the same time.<a name="line.37"></a>
<span class="sourceLineNo">038</span> *<a name="line.38"></a>
<span class="sourceLineNo">039</span> * A file called "filename.lock" is created and Java's FileLock class<a name="line.39"></a>
<span class="sourceLineNo">040</span> * is used to lock the file.<a name="line.40"></a>
<span class="sourceLineNo">041</span> *<a name="line.41"></a>
<span class="sourceLineNo">042</span> * The java.nio classes were introduced in Java 1.4, so this class<a name="line.42"></a>
<span class="sourceLineNo">043</span> * does a no-op when used with Java 1.3. The class maintains<a name="line.43"></a>
<span class="sourceLineNo">044</span> * compatability with Java 1.3 by accessing the java.nio classes<a name="line.44"></a>
<span class="sourceLineNo">045</span> * using reflection.<a name="line.45"></a>
<span class="sourceLineNo">046</span> *<a name="line.46"></a>
<span class="sourceLineNo">047</span> * @author John Lewis<a name="line.47"></a>
<span class="sourceLineNo">048</span> * @author Mark Doliner<a name="line.48"></a>
<span class="sourceLineNo">049</span> */<a name="line.49"></a>
<span class="sourceLineNo">050</span>public class FileLocker<a name="line.50"></a>
<span class="sourceLineNo">051</span>{<a name="line.51"></a>
<span class="sourceLineNo">052</span><a name="line.52"></a>
<span class="sourceLineNo">053</span> /**<a name="line.53"></a>
<span class="sourceLineNo">054</span> * An object of type FileLock, created using reflection.<a name="line.54"></a>
<span class="sourceLineNo">055</span> */<a name="line.55"></a>
<span class="sourceLineNo">056</span> private Object lock = null;<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> * An object of type FileChannel, created using reflection.<a name="line.59"></a>
<span class="sourceLineNo">060</span> */<a name="line.60"></a>
<span class="sourceLineNo">061</span> private Object lockChannel = null;<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 file called "filename.lock" that resides in the same directory<a name="line.64"></a>
<span class="sourceLineNo">065</span> * as "filename"<a name="line.65"></a>
<span class="sourceLineNo">066</span> */<a name="line.66"></a>
<span class="sourceLineNo">067</span> private File lockFile;<a name="line.67"></a>
<span class="sourceLineNo">068</span><a name="line.68"></a>
<span class="sourceLineNo">069</span> public FileLocker(File file)<a name="line.69"></a>
<span class="sourceLineNo">070</span> {<a name="line.70"></a>
<span class="sourceLineNo">071</span> String lockFileName = file.getName() + ".lock";<a name="line.71"></a>
<span class="sourceLineNo">072</span> File parent = file.getParentFile();<a name="line.72"></a>
<span class="sourceLineNo">073</span> if (parent == null)<a name="line.73"></a>
<span class="sourceLineNo">074</span> {<a name="line.74"></a>
<span class="sourceLineNo">075</span> lockFile = new File(lockFileName);<a name="line.75"></a>
<span class="sourceLineNo">076</span> }<a name="line.76"></a>
<span class="sourceLineNo">077</span> else<a name="line.77"></a>
<span class="sourceLineNo">078</span> {<a name="line.78"></a>
<span class="sourceLineNo">079</span> lockFile = new File(parent, lockFileName);<a name="line.79"></a>
<span class="sourceLineNo">080</span> }<a name="line.80"></a>
<span class="sourceLineNo">081</span> }<a name="line.81"></a>
<span class="sourceLineNo">082</span><a name="line.82"></a>
<span class="sourceLineNo">083</span> /**<a name="line.83"></a>
<span class="sourceLineNo">084</span> * Obtains a lock on the file. This blocks until the lock is obtained.<a name="line.84"></a>
<span class="sourceLineNo">085</span> */<a name="line.85"></a>
<span class="sourceLineNo">086</span> public boolean lock()<a name="line.86"></a>
<span class="sourceLineNo">087</span> {<a name="line.87"></a>
<span class="sourceLineNo">088</span> String useNioProperty = System.getProperty("cobertura.use.java.nio");<a name="line.88"></a>
<span class="sourceLineNo">089</span> if (System.getProperty("java.version").startsWith("1.3") ||<a name="line.89"></a>
<span class="sourceLineNo">090</span> ((useNioProperty != null) && useNioProperty.equalsIgnoreCase("false")))<a name="line.90"></a>
<span class="sourceLineNo">091</span> {<a name="line.91"></a>
<span class="sourceLineNo">092</span> return true;<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> try<a name="line.95"></a>
<span class="sourceLineNo">096</span> {<a name="line.96"></a>
<span class="sourceLineNo">097</span> Class aClass = Class.forName("java.io.RandomAccessFile");<a name="line.97"></a>
<span class="sourceLineNo">098</span> Method method = aClass.getDeclaredMethod("getChannel", (Class[])null);<a name="line.98"></a>
<span class="sourceLineNo">099</span> lockChannel = method.invoke(new RandomAccessFile(lockFile, "rw"), (Object[])null);<a name="line.99"></a>
<span class="sourceLineNo">100</span> }<a name="line.100"></a>
<span class="sourceLineNo">101</span> catch (FileNotFoundException e)<a name="line.101"></a>
<span class="sourceLineNo">102</span> {<a name="line.102"></a>
<span class="sourceLineNo">103</span> System.err.println("Unable to get lock channel for " + lockFile.getAbsolutePath()<a name="line.103"></a>
<span class="sourceLineNo">104</span> + ": " + e.getLocalizedMessage());<a name="line.104"></a>
<span class="sourceLineNo">105</span> return false;<a name="line.105"></a>
<span class="sourceLineNo">106</span> }<a name="line.106"></a>
<span class="sourceLineNo">107</span> catch (InvocationTargetException e)<a name="line.107"></a>
<span class="sourceLineNo">108</span> {<a name="line.108"></a>
<span class="sourceLineNo">109</span> System.err.println("Unable to get lock channel for " + lockFile.getAbsolutePath()<a name="line.109"></a>
<span class="sourceLineNo">110</span> + ": " + e.getLocalizedMessage());<a name="line.110"></a>
<span class="sourceLineNo">111</span> return false;<a name="line.111"></a>
<span class="sourceLineNo">112</span> }<a name="line.112"></a>
<span class="sourceLineNo">113</span> catch (Throwable t)<a name="line.113"></a>
<span class="sourceLineNo">114</span> {<a name="line.114"></a>
<span class="sourceLineNo">115</span> System.err.println("Unable to execute RandomAccessFile.getChannel() using reflection: "<a name="line.115"></a>
<span class="sourceLineNo">116</span> + t.getLocalizedMessage());<a name="line.116"></a>
<span class="sourceLineNo">117</span> t.printStackTrace();<a name="line.117"></a>
<span class="sourceLineNo">118</span> }<a name="line.118"></a>
<span class="sourceLineNo">119</span><a name="line.119"></a>
<span class="sourceLineNo">120</span> try<a name="line.120"></a>
<span class="sourceLineNo">121</span> {<a name="line.121"></a>
<span class="sourceLineNo">122</span> Class aClass = Class.forName("java.nio.channels.FileChannel");<a name="line.122"></a>
<span class="sourceLineNo">123</span> Method method = aClass.getDeclaredMethod("lock", (Class[])null);<a name="line.123"></a>
<span class="sourceLineNo">124</span> lock = method.invoke(lockChannel, (Object[])null);<a name="line.124"></a>
<span class="sourceLineNo">125</span> }<a name="line.125"></a>
<span class="sourceLineNo">126</span> catch (InvocationTargetException e)<a name="line.126"></a>
<span class="sourceLineNo">127</span> {<a name="line.127"></a>
<span class="sourceLineNo">128</span> System.err.println("---------------------------------------");<a name="line.128"></a>
<span class="sourceLineNo">129</span> e.printStackTrace(System.err);<a name="line.129"></a>
<span class="sourceLineNo">130</span> System.err.println("---------------------------------------");<a name="line.130"></a>
<span class="sourceLineNo">131</span> System.err.println("Unable to get lock on " + lockFile.getAbsolutePath() + ": "<a name="line.131"></a>
<span class="sourceLineNo">132</span> + e.getLocalizedMessage());<a name="line.132"></a>
<span class="sourceLineNo">133</span> System.err.println("This is known to happen on Linux kernel 2.6.20.");<a name="line.133"></a>
<span class="sourceLineNo">134</span> System.err.println("Make sure cobertura.jar is in the root classpath of the jvm ");<a name="line.134"></a>
<span class="sourceLineNo">135</span> System.err.println("process running the instrumented code. If the instrumented code ");<a name="line.135"></a>
<span class="sourceLineNo">136</span> System.err.println("is running in a web server, this means cobertura.jar should be in ");<a name="line.136"></a>
<span class="sourceLineNo">137</span> System.err.println("the web server's lib directory.");<a name="line.137"></a>
<span class="sourceLineNo">138</span> System.err.println("Don't put multiple copies of cobertura.jar in different WEB-INF/lib directories.");<a name="line.138"></a>
<span class="sourceLineNo">139</span> System.err.println("Only one classloader should load cobertura. It should be the root classloader.");<a name="line.139"></a>
<span class="sourceLineNo">140</span> System.err.println("---------------------------------------");<a name="line.140"></a>
<span class="sourceLineNo">141</span> return false;<a name="line.141"></a>
<span class="sourceLineNo">142</span> }<a name="line.142"></a>
<span class="sourceLineNo">143</span> catch (Throwable t)<a name="line.143"></a>
<span class="sourceLineNo">144</span> {<a name="line.144"></a>
<span class="sourceLineNo">145</span> System.err.println("Unable to execute FileChannel.lock() using reflection: "<a name="line.145"></a>
<span class="sourceLineNo">146</span> + t.getLocalizedMessage());<a name="line.146"></a>
<span class="sourceLineNo">147</span> t.printStackTrace();<a name="line.147"></a>
<span class="sourceLineNo">148</span> }<a name="line.148"></a>
<span class="sourceLineNo">149</span><a name="line.149"></a>
<span class="sourceLineNo">150</span> return true;<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> * Releases the lock on the file.<a name="line.154"></a>
<span class="sourceLineNo">155</span> */<a name="line.155"></a>
<span class="sourceLineNo">156</span> public void release()<a name="line.156"></a>
<span class="sourceLineNo">157</span> {<a name="line.157"></a>
<span class="sourceLineNo">158</span> if (lock != null)<a name="line.158"></a>
<span class="sourceLineNo">159</span> lock = releaseFileLock(lock);<a name="line.159"></a>
<span class="sourceLineNo">160</span> <a name="line.160"></a>
<span class="sourceLineNo">161</span> if (lockChannel != null)<a name="line.161"></a>
<span class="sourceLineNo">162</span> lockChannel = closeChannel(lockChannel);<a name="line.162"></a>
<span class="sourceLineNo">163</span> if (!lockFile.delete())<a name="line.163"></a>
<span class="sourceLineNo">164</span> {<a name="line.164"></a>
<span class="sourceLineNo">165</span> System.err.println("lock file could not be deleted");<a name="line.165"></a>
<span class="sourceLineNo">166</span> }<a name="line.166"></a>
<span class="sourceLineNo">167</span> }<a name="line.167"></a>
<span class="sourceLineNo">168</span><a name="line.168"></a>
<span class="sourceLineNo">169</span> private static Object releaseFileLock(Object lock)<a name="line.169"></a>
<span class="sourceLineNo">170</span> {<a name="line.170"></a>
<span class="sourceLineNo">171</span> try<a name="line.171"></a>
<span class="sourceLineNo">172</span> {<a name="line.172"></a>
<span class="sourceLineNo">173</span> Class aClass = Class.forName("java.nio.channels.FileLock");<a name="line.173"></a>
<span class="sourceLineNo">174</span> Method method = aClass.getDeclaredMethod("isValid", (Class[])null);<a name="line.174"></a>
<span class="sourceLineNo">175</span> if (((Boolean)method.invoke(lock, (Object[])null)).booleanValue())<a name="line.175"></a>
<span class="sourceLineNo">176</span> {<a name="line.176"></a>
<span class="sourceLineNo">177</span> method = aClass.getDeclaredMethod("release", (Class[])null);<a name="line.177"></a>
<span class="sourceLineNo">178</span> method.invoke(lock, (Object[])null);<a name="line.178"></a>
<span class="sourceLineNo">179</span> lock = null;<a name="line.179"></a>
<span class="sourceLineNo">180</span> }<a name="line.180"></a>
<span class="sourceLineNo">181</span> }<a name="line.181"></a>
<span class="sourceLineNo">182</span> catch (Throwable t)<a name="line.182"></a>
<span class="sourceLineNo">183</span> {<a name="line.183"></a>
<span class="sourceLineNo">184</span> System.err.println("Unable to release locked file: " + t.getLocalizedMessage());<a name="line.184"></a>
<span class="sourceLineNo">185</span> }<a name="line.185"></a>
<span class="sourceLineNo">186</span> return lock;<a name="line.186"></a>
<span class="sourceLineNo">187</span> }<a name="line.187"></a>
<span class="sourceLineNo">188</span><a name="line.188"></a>
<span class="sourceLineNo">189</span> private static Object closeChannel(Object channel)<a name="line.189"></a>
<span class="sourceLineNo">190</span> {<a name="line.190"></a>
<span class="sourceLineNo">191</span> try<a name="line.191"></a>
<span class="sourceLineNo">192</span> {<a name="line.192"></a>
<span class="sourceLineNo">193</span> Class aClass = Class.forName("java.nio.channels.spi.AbstractInterruptibleChannel");<a name="line.193"></a>
<span class="sourceLineNo">194</span> Method method = aClass.getDeclaredMethod("isOpen", (Class[])null);<a name="line.194"></a>
<span class="sourceLineNo">195</span> if (((Boolean)method.invoke(channel, (Object[])null)).booleanValue())<a name="line.195"></a>
<span class="sourceLineNo">196</span> {<a name="line.196"></a>
<span class="sourceLineNo">197</span> method = aClass.getDeclaredMethod("close", (Class[])null);<a name="line.197"></a>
<span class="sourceLineNo">198</span> method.invoke(channel, (Object[])null);<a name="line.198"></a>
<span class="sourceLineNo">199</span> channel = null;<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>
<span class="sourceLineNo">202</span> catch (Throwable t)<a name="line.202"></a>
<span class="sourceLineNo">203</span> {<a name="line.203"></a>
<span class="sourceLineNo">204</span> System.err.println("Unable to close file channel: " + t.getLocalizedMessage());<a name="line.204"></a>
<span class="sourceLineNo">205</span> }<a name="line.205"></a>
<span class="sourceLineNo">206</span> return channel;<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>}<a name="line.209"></a>
</pre>
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