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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 contributor license agreements. See the NOTICE file *<a name="line.2"></a>
<span class="sourceLineNo">003</span>// * distributed with this work for additional information regarding copyright ownership. The ASF licenses this file *<a name="line.3"></a>
<span class="sourceLineNo">004</span>// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance *<a name="line.4"></a>
<span class="sourceLineNo">005</span>// * with the License. You may obtain a copy of the License at *<a name="line.5"></a>
<span class="sourceLineNo">006</span>// * *<a name="line.6"></a>
<span class="sourceLineNo">007</span>// * http://www.apache.org/licenses/LICENSE-2.0 *<a name="line.7"></a>
<span class="sourceLineNo">008</span>// * *<a name="line.8"></a>
<span class="sourceLineNo">009</span>// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an *<a name="line.9"></a>
<span class="sourceLineNo">010</span>// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the *<a name="line.10"></a>
<span class="sourceLineNo">011</span>// * specific language governing permissions and limitations under the License. *<a name="line.11"></a>
<span class="sourceLineNo">012</span>// ***************************************************************************************************************************<a name="line.12"></a>
<span class="sourceLineNo">013</span>package org.apache.juneau.svl;<a name="line.13"></a>
<span class="sourceLineNo">014</span><a name="line.14"></a>
<span class="sourceLineNo">015</span>import static org.apache.juneau.internal.ArgUtils.*;<a name="line.15"></a>
<span class="sourceLineNo">016</span>import java.io.*;<a name="line.16"></a>
<span class="sourceLineNo">017</span><a name="line.17"></a>
<span class="sourceLineNo">018</span>/**<a name="line.18"></a>
<span class="sourceLineNo">019</span> * Abstract superclass of all Simple Var Language variables.<a name="line.19"></a>
<span class="sourceLineNo">020</span> *<a name="line.20"></a>
<span class="sourceLineNo">021</span> * &lt;p&gt;<a name="line.21"></a>
<span class="sourceLineNo">022</span> * Vars are used to convert simple variables of the form &lt;js&gt;"$varName{varKey}"&lt;/js&gt; into something else by the<a name="line.22"></a>
<span class="sourceLineNo">023</span> * {@link VarResolver} class.<a name="line.23"></a>
<span class="sourceLineNo">024</span> *<a name="line.24"></a>
<span class="sourceLineNo">025</span> * &lt;p&gt;<a name="line.25"></a>
<span class="sourceLineNo">026</span> * Subclasses must implement one of the following two methods:<a name="line.26"></a>
<span class="sourceLineNo">027</span> * &lt;ul class='javatree'&gt;<a name="line.27"></a>
<span class="sourceLineNo">028</span> * &lt;li class='jm'&gt;{@link #resolve(VarResolverSession,String)} - For simple vars.<a name="line.28"></a>
<span class="sourceLineNo">029</span> * &lt;li class='jm'&gt;{@link #resolveTo(VarResolverSession,Writer,String)} - For streamed vars.<a name="line.29"></a>
<span class="sourceLineNo">030</span> * &lt;/ul&gt;<a name="line.30"></a>
<span class="sourceLineNo">031</span> *<a name="line.31"></a>
<span class="sourceLineNo">032</span> * &lt;p&gt;<a name="line.32"></a>
<span class="sourceLineNo">033</span> * Subclasses MUST implement a no-arg constructor so that class names can be passed to the<a name="line.33"></a>
<span class="sourceLineNo">034</span> * {@link VarResolver.Builder#vars(Class...)} method.<a name="line.34"></a>
<span class="sourceLineNo">035</span> * &lt;br&gt;&lt;b&gt;They must also be thread safe!&lt;/b&gt;<a name="line.35"></a>
<span class="sourceLineNo">036</span> *<a name="line.36"></a>
<span class="sourceLineNo">037</span> * &lt;p&gt;<a name="line.37"></a>
<span class="sourceLineNo">038</span> * Two direct abstract subclasses are provided to differentiated between simple and streamed vars:<a name="line.38"></a>
<span class="sourceLineNo">039</span> * &lt;ul class='javatree'&gt;<a name="line.39"></a>
<span class="sourceLineNo">040</span> * &lt;li class='jac'&gt;{@link SimpleVar}<a name="line.40"></a>
<span class="sourceLineNo">041</span> * &lt;li class='jac'&gt;{@link StreamedVar}<a name="line.41"></a>
<span class="sourceLineNo">042</span> * &lt;/ul&gt;<a name="line.42"></a>
<span class="sourceLineNo">043</span> *<a name="line.43"></a>
<span class="sourceLineNo">044</span> * &lt;ul class='seealso'&gt;<a name="line.44"></a>
<span class="sourceLineNo">045</span> * &lt;li class='link'&gt;{@doc jm.SimpleVariableLanguage}<a name="line.45"></a>
<span class="sourceLineNo">046</span> * &lt;li class='extlink'&gt;{@source}<a name="line.46"></a>
<span class="sourceLineNo">047</span> * &lt;/ul&gt;<a name="line.47"></a>
<span class="sourceLineNo">048</span> */<a name="line.48"></a>
<span class="sourceLineNo">049</span>public abstract class Var {<a name="line.49"></a>
<span class="sourceLineNo">050</span><a name="line.50"></a>
<span class="sourceLineNo">051</span> private final String name;<a name="line.51"></a>
<span class="sourceLineNo">052</span> final boolean streamed;<a name="line.52"></a>
<span class="sourceLineNo">053</span><a name="line.53"></a>
<span class="sourceLineNo">054</span> /**<a name="line.54"></a>
<span class="sourceLineNo">055</span> * Constructor.<a name="line.55"></a>
<span class="sourceLineNo">056</span> *<a name="line.56"></a>
<span class="sourceLineNo">057</span> * @param name The name of this variable.<a name="line.57"></a>
<span class="sourceLineNo">058</span> * @param streamed<a name="line.58"></a>
<span class="sourceLineNo">059</span> * Whether this variable is 'streamed', meaning the {@link #resolveTo(VarResolverSession, Writer, String)} method<a name="line.59"></a>
<span class="sourceLineNo">060</span> * is implemented.<a name="line.60"></a>
<span class="sourceLineNo">061</span> * If &lt;jk&gt;false&lt;/jk&gt;, then the {@link #resolve(VarResolverSession, String)} method is implemented.<a name="line.61"></a>
<span class="sourceLineNo">062</span> */<a name="line.62"></a>
<span class="sourceLineNo">063</span> public Var(String name, boolean streamed) {<a name="line.63"></a>
<span class="sourceLineNo">064</span> assertArgNotNull("name", name);<a name="line.64"></a>
<span class="sourceLineNo">065</span> this.name = name;<a name="line.65"></a>
<span class="sourceLineNo">066</span> this.streamed = streamed;<a name="line.66"></a>
<span class="sourceLineNo">067</span><a name="line.67"></a>
<span class="sourceLineNo">068</span> for (int i = 0; i &lt; name.length(); i++) {<a name="line.68"></a>
<span class="sourceLineNo">069</span> // Need to make sure only ASCII characters are used.<a name="line.69"></a>
<span class="sourceLineNo">070</span> char c = name.charAt(i);<a name="line.70"></a>
<span class="sourceLineNo">071</span> if (c &lt; 'A' || c &gt; 'z' || (c &gt; 'Z' &amp;&amp; c &lt; 'a'))<a name="line.71"></a>
<span class="sourceLineNo">072</span> throw new IllegalArgumentException("Invalid var name. Must consist of only uppercase and lowercase ASCII letters.");<a name="line.72"></a>
<span class="sourceLineNo">073</span> }<a name="line.73"></a>
<span class="sourceLineNo">074</span> }<a name="line.74"></a>
<span class="sourceLineNo">075</span><a name="line.75"></a>
<span class="sourceLineNo">076</span> /**<a name="line.76"></a>
<span class="sourceLineNo">077</span> * Return the name of this variable.<a name="line.77"></a>
<span class="sourceLineNo">078</span> *<a name="line.78"></a>
<span class="sourceLineNo">079</span> * &lt;p&gt;<a name="line.79"></a>
<span class="sourceLineNo">080</span> * For example, the system property variable returns &lt;js&gt;"S"&lt;/js&gt; since the format of the variable is<a name="line.80"></a>
<span class="sourceLineNo">081</span> * &lt;js&gt;"$S{system.property}"&lt;/js&gt;.<a name="line.81"></a>
<span class="sourceLineNo">082</span> *<a name="line.82"></a>
<span class="sourceLineNo">083</span> * @return The name of this variable.<a name="line.83"></a>
<span class="sourceLineNo">084</span> */<a name="line.84"></a>
<span class="sourceLineNo">085</span> protected String getName() {<a name="line.85"></a>
<span class="sourceLineNo">086</span> return name;<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> * Returns whether nested variables are supported by this variable.<a name="line.90"></a>
<span class="sourceLineNo">091</span> *<a name="line.91"></a>
<span class="sourceLineNo">092</span> * &lt;p&gt;<a name="line.92"></a>
<span class="sourceLineNo">093</span> * For example, in &lt;js&gt;"$X{$Y{xxx}}"&lt;/js&gt;, $Y is a nested variable that will be resolved if this method returns<a name="line.93"></a>
<span class="sourceLineNo">094</span> * &lt;jk&gt;true&lt;/jk&gt;.<a name="line.94"></a>
<span class="sourceLineNo">095</span> *<a name="line.95"></a>
<span class="sourceLineNo">096</span> * &lt;p&gt;<a name="line.96"></a>
<span class="sourceLineNo">097</span> * The default implementation of this method always returns &lt;jk&gt;true&lt;/jk&gt;.<a name="line.97"></a>
<span class="sourceLineNo">098</span> * Subclasses can override this method to override the default behavior.<a name="line.98"></a>
<span class="sourceLineNo">099</span> *<a name="line.99"></a>
<span class="sourceLineNo">100</span> * @return &lt;jk&gt;true&lt;/jk&gt; if nested variables are supported by this variable.<a name="line.100"></a>
<span class="sourceLineNo">101</span> */<a name="line.101"></a>
<span class="sourceLineNo">102</span> protected boolean allowNested() {<a name="line.102"></a>
<span class="sourceLineNo">103</span> return true;<a name="line.103"></a>
<span class="sourceLineNo">104</span> }<a name="line.104"></a>
<span class="sourceLineNo">105</span><a name="line.105"></a>
<span class="sourceLineNo">106</span> /**<a name="line.106"></a>
<span class="sourceLineNo">107</span> * Returns whether variables in the resolved contents of this variable should also be resolved.<a name="line.107"></a>
<span class="sourceLineNo">108</span> *<a name="line.108"></a>
<span class="sourceLineNo">109</span> * &lt;p&gt;<a name="line.109"></a>
<span class="sourceLineNo">110</span> * For example, if &lt;js&gt;"$X{xxx}"&lt;/js&gt; resolves to &lt;js&gt;"$Y{xxx}"&lt;/js&gt;, then the $Y variable will be recursively<a name="line.110"></a>
<span class="sourceLineNo">111</span> * resolved if this method returns &lt;jk&gt;true&lt;/jk&gt;.<a name="line.111"></a>
<span class="sourceLineNo">112</span> *<a name="line.112"></a>
<span class="sourceLineNo">113</span> * &lt;p&gt;<a name="line.113"></a>
<span class="sourceLineNo">114</span> * The default implementation of this method always returns &lt;jk&gt;true&lt;/jk&gt;.<a name="line.114"></a>
<span class="sourceLineNo">115</span> * &lt;br&gt;Subclasses can override this method to override the default behavior.<a name="line.115"></a>
<span class="sourceLineNo">116</span> *<a name="line.116"></a>
<span class="sourceLineNo">117</span> * &lt;div class='warn'&gt;<a name="line.117"></a>
<span class="sourceLineNo">118</span> * As a general rule, variables that resolve user-entered data should not be recursively resolved as this may<a name="line.118"></a>
<span class="sourceLineNo">119</span> * cause a security hole.<a name="line.119"></a>
<span class="sourceLineNo">120</span> * &lt;/div&gt;<a name="line.120"></a>
<span class="sourceLineNo">121</span> *<a name="line.121"></a>
<span class="sourceLineNo">122</span> * @return &lt;jk&gt;true&lt;/jk&gt; if resolved variables should be recursively resolved.<a name="line.122"></a>
<span class="sourceLineNo">123</span> */<a name="line.123"></a>
<span class="sourceLineNo">124</span> protected boolean allowRecurse() {<a name="line.124"></a>
<span class="sourceLineNo">125</span> return true;<a name="line.125"></a>
<span class="sourceLineNo">126</span> }<a name="line.126"></a>
<span class="sourceLineNo">127</span><a name="line.127"></a>
<span class="sourceLineNo">128</span> /**<a name="line.128"></a>
<span class="sourceLineNo">129</span> * Returns &lt;jk&gt;true&lt;/jk&gt; if this variable can be resolved in the specified session.<a name="line.129"></a>
<span class="sourceLineNo">130</span> *<a name="line.130"></a>
<span class="sourceLineNo">131</span> * &lt;p&gt;<a name="line.131"></a>
<span class="sourceLineNo">132</span> * For example, some variable cannot resolve unless specific context or session objects are available.<a name="line.132"></a>
<span class="sourceLineNo">133</span> *<a name="line.133"></a>
<span class="sourceLineNo">134</span> * @param session The current session.<a name="line.134"></a>
<span class="sourceLineNo">135</span> * @return &lt;jk&gt;true&lt;/jk&gt; if this variable can be resolved in the specified session.<a name="line.135"></a>
<span class="sourceLineNo">136</span> */<a name="line.136"></a>
<span class="sourceLineNo">137</span> protected boolean canResolve(VarResolverSession session) {<a name="line.137"></a>
<span class="sourceLineNo">138</span> return true;<a name="line.138"></a>
<span class="sourceLineNo">139</span> }<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> * The method called from {@link VarResolver}.<a name="line.142"></a>
<span class="sourceLineNo">143</span> *<a name="line.143"></a>
<span class="sourceLineNo">144</span> * &lt;p&gt;<a name="line.144"></a>
<span class="sourceLineNo">145</span> * Can be overridden to intercept the request and do special handling.<a name="line.145"></a>
<span class="sourceLineNo">146</span> * &lt;br&gt;Default implementation simply calls resolve(String).<a name="line.146"></a>
<span class="sourceLineNo">147</span> *<a name="line.147"></a>
<span class="sourceLineNo">148</span> * @param session The session object used for a single instance of a string resolution.<a name="line.148"></a>
<span class="sourceLineNo">149</span> * @param arg The inside argument of the variable.<a name="line.149"></a>
<span class="sourceLineNo">150</span> * @return The resolved value.<a name="line.150"></a>
<span class="sourceLineNo">151</span> * @throws Exception Any exception can be thrown.<a name="line.151"></a>
<span class="sourceLineNo">152</span> */<a name="line.152"></a>
<span class="sourceLineNo">153</span> protected String doResolve(VarResolverSession session, String arg) throws Exception {<a name="line.153"></a>
<span class="sourceLineNo">154</span> return resolve(session, arg);<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> /**<a name="line.157"></a>
<span class="sourceLineNo">158</span> * The interface that needs to be implemented for subclasses of {@link SimpleVar}.<a name="line.158"></a>
<span class="sourceLineNo">159</span> *<a name="line.159"></a>
<span class="sourceLineNo">160</span> * @param session The session object used for a single instance of a var resolution.<a name="line.160"></a>
<span class="sourceLineNo">161</span> * @param arg The inside argument of the variable.<a name="line.161"></a>
<span class="sourceLineNo">162</span> * @return The resolved value.<a name="line.162"></a>
<span class="sourceLineNo">163</span> * @throws Exception Any exception can be thrown.<a name="line.163"></a>
<span class="sourceLineNo">164</span> */<a name="line.164"></a>
<span class="sourceLineNo">165</span> public abstract String resolve(VarResolverSession session, String arg) throws Exception;<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> * The interface that needs to be implemented for subclasses of {@link StreamedVar}.<a name="line.168"></a>
<span class="sourceLineNo">169</span> *<a name="line.169"></a>
<span class="sourceLineNo">170</span> * @param session The session object used for a single instance of a var resolution.<a name="line.170"></a>
<span class="sourceLineNo">171</span> * @param w The writer to send the resolved value to.<a name="line.171"></a>
<span class="sourceLineNo">172</span> * @param arg The inside argument of the variable.<a name="line.172"></a>
<span class="sourceLineNo">173</span> * @throws Exception Any exception can be thrown.<a name="line.173"></a>
<span class="sourceLineNo">174</span> */<a name="line.174"></a>
<span class="sourceLineNo">175</span> public abstract void resolveTo(VarResolverSession session, Writer w, String arg) throws Exception;<a name="line.175"></a>
<span class="sourceLineNo">176</span>}<a name="line.176"></a>
</pre>
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