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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 or more<a name="line.2"></a>
<span class="sourceLineNo">003</span> * contributor license agreements. See the NOTICE file distributed with<a name="line.3"></a>
<span class="sourceLineNo">004</span> * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<span class="sourceLineNo">005</span> * The ASF licenses this file to You under the Apache license, Version 2.0<a name="line.5"></a>
<span class="sourceLineNo">006</span> * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<span class="sourceLineNo">007</span> * the License. You may obtain a copy of the License at<a name="line.7"></a>
<span class="sourceLineNo">008</span> *<a name="line.8"></a>
<span class="sourceLineNo">009</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<span class="sourceLineNo">010</span> *<a name="line.10"></a>
<span class="sourceLineNo">011</span> * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<span class="sourceLineNo">012</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<span class="sourceLineNo">013</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<span class="sourceLineNo">014</span> * See the license for the specific language governing permissions and<a name="line.14"></a>
<span class="sourceLineNo">015</span> * limitations under the license.<a name="line.15"></a>
<span class="sourceLineNo">016</span> */<a name="line.16"></a>
<span class="sourceLineNo">017</span>package org.apache.logging.log4j.core.config;<a name="line.17"></a>
<span class="sourceLineNo">018</span><a name="line.18"></a>
<span class="sourceLineNo">019</span>import java.util.Arrays;<a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.util.HashMap;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.util.Map;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.util.Objects;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.util.concurrent.atomic.AtomicReference;<a name="line.23"></a>
<span class="sourceLineNo">024</span><a name="line.24"></a>
<span class="sourceLineNo">025</span>import org.apache.logging.log4j.core.Appender;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import org.apache.logging.log4j.util.PerformanceSensitive;<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> * Data structure with similar semantics to CopyOnWriteArraySet, but giving direct access to the underlying array.<a name="line.29"></a>
<span class="sourceLineNo">030</span> *<a name="line.30"></a>
<span class="sourceLineNo">031</span> * @since 2.6<a name="line.31"></a>
<span class="sourceLineNo">032</span> */<a name="line.32"></a>
<span class="sourceLineNo">033</span>@PerformanceSensitive<a name="line.33"></a>
<span class="sourceLineNo">034</span>public class AppenderControlArraySet {<a name="line.34"></a>
<span class="sourceLineNo">035</span> private final AtomicReference&lt;AppenderControl[]&gt; appenderArray = new AtomicReference&lt;&gt;(new AppenderControl[0]);<a name="line.35"></a>
<span class="sourceLineNo">036</span><a name="line.36"></a>
<span class="sourceLineNo">037</span> /**<a name="line.37"></a>
<span class="sourceLineNo">038</span> * Adds an AppenderControl to this set. If this set already contains the element, the call leaves the set unchanged<a name="line.38"></a>
<span class="sourceLineNo">039</span> * and returns false.<a name="line.39"></a>
<span class="sourceLineNo">040</span> *<a name="line.40"></a>
<span class="sourceLineNo">041</span> * @param control The AppenderControl to add.<a name="line.41"></a>
<span class="sourceLineNo">042</span> * @return true if this set did not already contain the specified element<a name="line.42"></a>
<span class="sourceLineNo">043</span> */<a name="line.43"></a>
<span class="sourceLineNo">044</span> public boolean add(final AppenderControl control) {<a name="line.44"></a>
<span class="sourceLineNo">045</span> boolean success;<a name="line.45"></a>
<span class="sourceLineNo">046</span> do {<a name="line.46"></a>
<span class="sourceLineNo">047</span> final AppenderControl[] original = appenderArray.get();<a name="line.47"></a>
<span class="sourceLineNo">048</span> for (final AppenderControl existing : original) {<a name="line.48"></a>
<span class="sourceLineNo">049</span> if (existing.equals(control)) {<a name="line.49"></a>
<span class="sourceLineNo">050</span> return false; // the appender is already in the list<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> final AppenderControl[] copy = Arrays.copyOf(original, original.length + 1);<a name="line.53"></a>
<span class="sourceLineNo">054</span> copy[copy.length - 1] = control;<a name="line.54"></a>
<span class="sourceLineNo">055</span> success = appenderArray.compareAndSet(original, copy);<a name="line.55"></a>
<span class="sourceLineNo">056</span> } while (!success); // could not swap: array was modified by another thread<a name="line.56"></a>
<span class="sourceLineNo">057</span> return true; // successfully added<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> /**<a name="line.60"></a>
<span class="sourceLineNo">061</span> * Removes the AppenderControl with the specific name and returns it (or {@code null} if no such appender existed).<a name="line.61"></a>
<span class="sourceLineNo">062</span> *<a name="line.62"></a>
<span class="sourceLineNo">063</span> * @param name The name of the AppenderControl to remove<a name="line.63"></a>
<span class="sourceLineNo">064</span> * @return the removed AppenderControl or {@code null}<a name="line.64"></a>
<span class="sourceLineNo">065</span> */<a name="line.65"></a>
<span class="sourceLineNo">066</span> public AppenderControl remove(final String name) {<a name="line.66"></a>
<span class="sourceLineNo">067</span> boolean success;<a name="line.67"></a>
<span class="sourceLineNo">068</span> do {<a name="line.68"></a>
<span class="sourceLineNo">069</span> success = true;<a name="line.69"></a>
<span class="sourceLineNo">070</span> final AppenderControl[] original = appenderArray.get();<a name="line.70"></a>
<span class="sourceLineNo">071</span> for (int i = 0; i &lt; original.length; i++) {<a name="line.71"></a>
<span class="sourceLineNo">072</span> final AppenderControl appenderControl = original[i];<a name="line.72"></a>
<span class="sourceLineNo">073</span> if (Objects.equals(name, appenderControl.getAppenderName())) {<a name="line.73"></a>
<span class="sourceLineNo">074</span> final AppenderControl[] copy = removeElementAt(i, original);<a name="line.74"></a>
<span class="sourceLineNo">075</span> if (appenderArray.compareAndSet(original, copy)) {<a name="line.75"></a>
<span class="sourceLineNo">076</span> return appenderControl; // successfully removed<a name="line.76"></a>
<span class="sourceLineNo">077</span> }<a name="line.77"></a>
<span class="sourceLineNo">078</span> success = false; // could not swap: array was modified by another thread<a name="line.78"></a>
<span class="sourceLineNo">079</span> break;<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> } while (!success);<a name="line.82"></a>
<span class="sourceLineNo">083</span> return null; // not found<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> private AppenderControl[] removeElementAt(final int i, final AppenderControl[] array) {<a name="line.86"></a>
<span class="sourceLineNo">087</span> final AppenderControl[] result = Arrays.copyOf(array, array.length - 1);<a name="line.87"></a>
<span class="sourceLineNo">088</span> System.arraycopy(array, i + 1, result, i, result.length - i);<a name="line.88"></a>
<span class="sourceLineNo">089</span> return result;<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> /**<a name="line.92"></a>
<span class="sourceLineNo">093</span> * Returns all Appenders as a Map.<a name="line.93"></a>
<span class="sourceLineNo">094</span> *<a name="line.94"></a>
<span class="sourceLineNo">095</span> * @return a Map with the Appender name as the key and the Appender as the value.<a name="line.95"></a>
<span class="sourceLineNo">096</span> */<a name="line.96"></a>
<span class="sourceLineNo">097</span> public Map&lt;String, Appender&gt; asMap() {<a name="line.97"></a>
<span class="sourceLineNo">098</span> final Map&lt;String, Appender&gt; result = new HashMap&lt;&gt;();<a name="line.98"></a>
<span class="sourceLineNo">099</span> for (final AppenderControl appenderControl : appenderArray.get()) {<a name="line.99"></a>
<span class="sourceLineNo">100</span> result.put(appenderControl.getAppenderName(), appenderControl.getAppender());<a name="line.100"></a>
<span class="sourceLineNo">101</span> }<a name="line.101"></a>
<span class="sourceLineNo">102</span> return result;<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> /**<a name="line.105"></a>
<span class="sourceLineNo">106</span> * Atomically sets the values to an empty array and returns the old array.<a name="line.106"></a>
<span class="sourceLineNo">107</span> *<a name="line.107"></a>
<span class="sourceLineNo">108</span> * @return the contents before this collection was cleared.<a name="line.108"></a>
<span class="sourceLineNo">109</span> */<a name="line.109"></a>
<span class="sourceLineNo">110</span> public AppenderControl[] clear() {<a name="line.110"></a>
<span class="sourceLineNo">111</span> return appenderArray.getAndSet(new AppenderControl[0]);<a name="line.111"></a>
<span class="sourceLineNo">112</span> }<a name="line.112"></a>
<span class="sourceLineNo">113</span><a name="line.113"></a>
<span class="sourceLineNo">114</span> public boolean isEmpty() {<a name="line.114"></a>
<span class="sourceLineNo">115</span> return appenderArray.get().length == 0;<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> /**<a name="line.118"></a>
<span class="sourceLineNo">119</span> * Returns the underlying array.<a name="line.119"></a>
<span class="sourceLineNo">120</span> *<a name="line.120"></a>
<span class="sourceLineNo">121</span> * @return the array supporting this collection<a name="line.121"></a>
<span class="sourceLineNo">122</span> */<a name="line.122"></a>
<span class="sourceLineNo">123</span> public AppenderControl[] get() {<a name="line.123"></a>
<span class="sourceLineNo">124</span> return appenderArray.get();<a name="line.124"></a>
<span class="sourceLineNo">125</span> }<a name="line.125"></a>
<span class="sourceLineNo">126</span><a name="line.126"></a>
<span class="sourceLineNo">127</span> @Override<a name="line.127"></a>
<span class="sourceLineNo">128</span> public String toString() {<a name="line.128"></a>
<span class="sourceLineNo">129</span> return "AppenderControlArraySet [appenderArray=" + appenderArray + "]";<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>
</pre>
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