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apache / logging-log4j-site / d0d0de55986756593c08e5d2b8059541eacaf428 / . / log4j-2.0-alpha1-SNAPSHOT / log4j-core / apidocs / src-html / org / apache / logging / log4j / core / lookup / Interpolator.html
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<FONT color="green">001</FONT> /*<a name="line.1"></a>
<FONT color="green">002</FONT> * Licensed to the Apache Software Foundation (ASF) under one or more<a name="line.2"></a>
<FONT color="green">003</FONT> * contributor license agreements. See the NOTICE file distributed with<a name="line.3"></a>
<FONT color="green">004</FONT> * this work for additional information regarding copyright ownership.<a name="line.4"></a>
<FONT color="green">005</FONT> * The ASF licenses this file to You under the Apache license, Version 2.0<a name="line.5"></a>
<FONT color="green">006</FONT> * (the "License"); you may not use this file except in compliance with<a name="line.6"></a>
<FONT color="green">007</FONT> * the License. You may obtain a copy of the License at<a name="line.7"></a>
<FONT color="green">008</FONT> *<a name="line.8"></a>
<FONT color="green">009</FONT> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.9"></a>
<FONT color="green">010</FONT> *<a name="line.10"></a>
<FONT color="green">011</FONT> * Unless required by applicable law or agreed to in writing, software<a name="line.11"></a>
<FONT color="green">012</FONT> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.12"></a>
<FONT color="green">013</FONT> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.13"></a>
<FONT color="green">014</FONT> * See the license for the specific language governing permissions and<a name="line.14"></a>
<FONT color="green">015</FONT> * limitations under the license.<a name="line.15"></a>
<FONT color="green">016</FONT> */<a name="line.16"></a>
<FONT color="green">017</FONT> package org.apache.logging.log4j.core.lookup;<a name="line.17"></a>
<FONT color="green">018</FONT> <a name="line.18"></a>
<FONT color="green">019</FONT> import org.apache.logging.log4j.Logger;<a name="line.19"></a>
<FONT color="green">020</FONT> import org.apache.logging.log4j.core.LogEvent;<a name="line.20"></a>
<FONT color="green">021</FONT> import org.apache.logging.log4j.core.config.plugins.PluginManager;<a name="line.21"></a>
<FONT color="green">022</FONT> import org.apache.logging.log4j.core.config.plugins.PluginType;<a name="line.22"></a>
<FONT color="green">023</FONT> import org.apache.logging.log4j.status.StatusLogger;<a name="line.23"></a>
<FONT color="green">024</FONT> <a name="line.24"></a>
<FONT color="green">025</FONT> import java.util.HashMap;<a name="line.25"></a>
<FONT color="green">026</FONT> import java.util.Map;<a name="line.26"></a>
<FONT color="green">027</FONT> <a name="line.27"></a>
<FONT color="green">028</FONT> /**<a name="line.28"></a>
<FONT color="green">029</FONT> * The Interpolator is a StrLookup that acts as a proxy for all the other StrLookups.<a name="line.29"></a>
<FONT color="green">030</FONT> */<a name="line.30"></a>
<FONT color="green">031</FONT> public class Interpolator implements StrLookup {<a name="line.31"></a>
<FONT color="green">032</FONT> <a name="line.32"></a>
<FONT color="green">033</FONT> private static final Logger LOGGER = StatusLogger.getLogger();<a name="line.33"></a>
<FONT color="green">034</FONT> <a name="line.34"></a>
<FONT color="green">035</FONT> /** Constant for the prefix separator. */<a name="line.35"></a>
<FONT color="green">036</FONT> private static final char PREFIX_SEPARATOR = ':';<a name="line.36"></a>
<FONT color="green">037</FONT> <a name="line.37"></a>
<FONT color="green">038</FONT> private final Map&lt;String, StrLookup&gt; lookups = new HashMap&lt;String, StrLookup&gt;();<a name="line.38"></a>
<FONT color="green">039</FONT> <a name="line.39"></a>
<FONT color="green">040</FONT> private final StrLookup defaultLookup;<a name="line.40"></a>
<FONT color="green">041</FONT> <a name="line.41"></a>
<FONT color="green">042</FONT> public Interpolator(StrLookup defaultLookup) {<a name="line.42"></a>
<FONT color="green">043</FONT> this.defaultLookup = defaultLookup == null ? new MapLookup(new HashMap&lt;String, String&gt;()) : defaultLookup;<a name="line.43"></a>
<FONT color="green">044</FONT> PluginManager manager = new PluginManager("Lookup");<a name="line.44"></a>
<FONT color="green">045</FONT> manager.collectPlugins();<a name="line.45"></a>
<FONT color="green">046</FONT> Map&lt;String, PluginType&gt; plugins = manager.getPlugins();<a name="line.46"></a>
<FONT color="green">047</FONT> <a name="line.47"></a>
<FONT color="green">048</FONT> for (Map.Entry&lt;String, PluginType&gt; entry : plugins.entrySet()) {<a name="line.48"></a>
<FONT color="green">049</FONT> Class&lt;StrLookup&gt; clazz = entry.getValue().getPluginClass();<a name="line.49"></a>
<FONT color="green">050</FONT> try {<a name="line.50"></a>
<FONT color="green">051</FONT> lookups.put(entry.getKey(), clazz.newInstance());<a name="line.51"></a>
<FONT color="green">052</FONT> } catch (Exception ex) {<a name="line.52"></a>
<FONT color="green">053</FONT> LOGGER.error("Unable to create Lookup for " + entry.getKey(), ex);<a name="line.53"></a>
<FONT color="green">054</FONT> }<a name="line.54"></a>
<FONT color="green">055</FONT> }<a name="line.55"></a>
<FONT color="green">056</FONT> }<a name="line.56"></a>
<FONT color="green">057</FONT> <a name="line.57"></a>
<FONT color="green">058</FONT> /**<a name="line.58"></a>
<FONT color="green">059</FONT> * Resolves the specified variable. This implementation will try to extract<a name="line.59"></a>
<FONT color="green">060</FONT> * a variable prefix from the given variable name (the first colon (':') is<a name="line.60"></a>
<FONT color="green">061</FONT> * used as prefix separator). It then passes the name of the variable with<a name="line.61"></a>
<FONT color="green">062</FONT> * the prefix stripped to the lookup object registered for this prefix. If<a name="line.62"></a>
<FONT color="green">063</FONT> * no prefix can be found or if the associated lookup object cannot resolve<a name="line.63"></a>
<FONT color="green">064</FONT> * this variable, the default lookup object will be used.<a name="line.64"></a>
<FONT color="green">065</FONT> *<a name="line.65"></a>
<FONT color="green">066</FONT> * @param var the name of the variable whose value is to be looked up<a name="line.66"></a>
<FONT color="green">067</FONT> * @return the value of this variable or &lt;b&gt;null&lt;/b&gt; if it cannot be<a name="line.67"></a>
<FONT color="green">068</FONT> * resolved<a name="line.68"></a>
<FONT color="green">069</FONT> */<a name="line.69"></a>
<FONT color="green">070</FONT> public String lookup(String var) {<a name="line.70"></a>
<FONT color="green">071</FONT> return lookup(null, var);<a name="line.71"></a>
<FONT color="green">072</FONT> }<a name="line.72"></a>
<FONT color="green">073</FONT> <a name="line.73"></a>
<FONT color="green">074</FONT> /**<a name="line.74"></a>
<FONT color="green">075</FONT> * Resolves the specified variable. This implementation will try to extract<a name="line.75"></a>
<FONT color="green">076</FONT> * a variable prefix from the given variable name (the first colon (':') is<a name="line.76"></a>
<FONT color="green">077</FONT> * used as prefix separator). It then passes the name of the variable with<a name="line.77"></a>
<FONT color="green">078</FONT> * the prefix stripped to the lookup object registered for this prefix. If<a name="line.78"></a>
<FONT color="green">079</FONT> * no prefix can be found or if the associated lookup object cannot resolve<a name="line.79"></a>
<FONT color="green">080</FONT> * this variable, the default lookup object will be used.<a name="line.80"></a>
<FONT color="green">081</FONT> *<a name="line.81"></a>
<FONT color="green">082</FONT> * @param event The current LogEvent or null.<a name="line.82"></a>
<FONT color="green">083</FONT> * @param var the name of the variable whose value is to be looked up<a name="line.83"></a>
<FONT color="green">084</FONT> * @return the value of this variable or &lt;b&gt;null&lt;/b&gt; if it cannot be<a name="line.84"></a>
<FONT color="green">085</FONT> * resolved<a name="line.85"></a>
<FONT color="green">086</FONT> */<a name="line.86"></a>
<FONT color="green">087</FONT> public String lookup(LogEvent event, String var) {<a name="line.87"></a>
<FONT color="green">088</FONT> if (var == null) {<a name="line.88"></a>
<FONT color="green">089</FONT> return null;<a name="line.89"></a>
<FONT color="green">090</FONT> }<a name="line.90"></a>
<FONT color="green">091</FONT> <a name="line.91"></a>
<FONT color="green">092</FONT> int prefixPos = var.indexOf(PREFIX_SEPARATOR);<a name="line.92"></a>
<FONT color="green">093</FONT> if (prefixPos &gt;= 0) {<a name="line.93"></a>
<FONT color="green">094</FONT> String prefix = var.substring(0, prefixPos);<a name="line.94"></a>
<FONT color="green">095</FONT> String name = var.substring(prefixPos + 1);<a name="line.95"></a>
<FONT color="green">096</FONT> StrLookup lookup = lookups.get(prefix);<a name="line.96"></a>
<FONT color="green">097</FONT> String value = null;<a name="line.97"></a>
<FONT color="green">098</FONT> if (lookup != null) {<a name="line.98"></a>
<FONT color="green">099</FONT> value = event == null ? lookup.lookup(name) : lookup.lookup(event, name);<a name="line.99"></a>
<FONT color="green">100</FONT> }<a name="line.100"></a>
<FONT color="green">101</FONT> <a name="line.101"></a>
<FONT color="green">102</FONT> if (value != null) {<a name="line.102"></a>
<FONT color="green">103</FONT> return value;<a name="line.103"></a>
<FONT color="green">104</FONT> }<a name="line.104"></a>
<FONT color="green">105</FONT> var = var.substring(prefixPos);<a name="line.105"></a>
<FONT color="green">106</FONT> }<a name="line.106"></a>
<FONT color="green">107</FONT> if (defaultLookup != null) {<a name="line.107"></a>
<FONT color="green">108</FONT> return event == null ? defaultLookup.lookup(var) : defaultLookup.lookup(event, var);<a name="line.108"></a>
<FONT color="green">109</FONT> }<a name="line.109"></a>
<FONT color="green">110</FONT> return null;<a name="line.110"></a>
<FONT color="green">111</FONT> }<a name="line.111"></a>
<FONT color="green">112</FONT> <a name="line.112"></a>
<FONT color="green">113</FONT> public String toString() {<a name="line.113"></a>
<FONT color="green">114</FONT> StringBuilder sb = new StringBuilder();<a name="line.114"></a>
<FONT color="green">115</FONT> for (String name : lookups.keySet()) {<a name="line.115"></a>
<FONT color="green">116</FONT> if (sb.length() == 0) {<a name="line.116"></a>
<FONT color="green">117</FONT> sb.append("{");<a name="line.117"></a>
<FONT color="green">118</FONT> } else {<a name="line.118"></a>
<FONT color="green">119</FONT> sb.append(", ");<a name="line.119"></a>
<FONT color="green">120</FONT> }<a name="line.120"></a>
<FONT color="green">121</FONT> <a name="line.121"></a>
<FONT color="green">122</FONT> sb.append(name);<a name="line.122"></a>
<FONT color="green">123</FONT> }<a name="line.123"></a>
<FONT color="green">124</FONT> if (sb.length() &gt; 0) {<a name="line.124"></a>
<FONT color="green">125</FONT> sb.append("}");<a name="line.125"></a>
<FONT color="green">126</FONT> }<a name="line.126"></a>
<FONT color="green">127</FONT> return sb.toString();<a name="line.127"></a>
<FONT color="green">128</FONT> }<a name="line.128"></a>
<FONT color="green">129</FONT> }<a name="line.129"></a>
</PRE>
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