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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<a name="line.2"></a>
<FONT color="green">003</FONT>     * or more contributor license agreements. See the NOTICE file<a name="line.3"></a>
<FONT color="green">004</FONT>     * distributed with this work for additional information<a name="line.4"></a>
<FONT color="green">005</FONT>     * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a>
<FONT color="green">006</FONT>     * to you under the Apache License, Version 2.0 (the  "License");<a name="line.6"></a>
<FONT color="green">007</FONT>     * you may not use this file except in compliance with the License.<a name="line.7"></a>
<FONT color="green">008</FONT>     * You may obtain a copy of the License at<a name="line.8"></a>
<FONT color="green">009</FONT>     *<a name="line.9"></a>
<FONT color="green">010</FONT>     *     http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a>
<FONT color="green">011</FONT>     *<a name="line.11"></a>
<FONT color="green">012</FONT>     * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a>
<FONT color="green">013</FONT>     * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<FONT color="green">014</FONT>     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<FONT color="green">015</FONT>     * See the License for the specific language governing permissions and<a name="line.15"></a>
<FONT color="green">016</FONT>     * limitations under the License.<a name="line.16"></a>
<FONT color="green">017</FONT>     */<a name="line.17"></a>
<FONT color="green">018</FONT>    /*<a name="line.18"></a>
<FONT color="green">019</FONT>     * $Id: ObjectPool.java 475981 2006-11-16 23:35:53Z minchau $<a name="line.19"></a>
<FONT color="green">020</FONT>     */<a name="line.20"></a>
<FONT color="green">021</FONT>    package org.apache.xml.utils;<a name="line.21"></a>
<FONT color="green">022</FONT>    <a name="line.22"></a>
<FONT color="green">023</FONT>    import java.util.ArrayList;<a name="line.23"></a>
<FONT color="green">024</FONT>    <a name="line.24"></a>
<FONT color="green">025</FONT>    import org.apache.xml.res.XMLErrorResources;<a name="line.25"></a>
<FONT color="green">026</FONT>    import org.apache.xml.res.XMLMessages;<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>    /**<a name="line.29"></a>
<FONT color="green">030</FONT>     * Pool of object of a given type to pick from to help memory usage<a name="line.30"></a>
<FONT color="green">031</FONT>     * @xsl.usage internal<a name="line.31"></a>
<FONT color="green">032</FONT>     */<a name="line.32"></a>
<FONT color="green">033</FONT>    public class ObjectPool implements java.io.Serializable<a name="line.33"></a>
<FONT color="green">034</FONT>    {<a name="line.34"></a>
<FONT color="green">035</FONT>        static final long serialVersionUID = -8519013691660936643L;<a name="line.35"></a>
<FONT color="green">036</FONT>    <a name="line.36"></a>
<FONT color="green">037</FONT>      /** Type of objects in this pool.<a name="line.37"></a>
<FONT color="green">038</FONT>       *  @serial          */<a name="line.38"></a>
<FONT color="green">039</FONT>      private final Class objectType;<a name="line.39"></a>
<FONT color="green">040</FONT>    <a name="line.40"></a>
<FONT color="green">041</FONT>      /** Stack of given objects this points to.<a name="line.41"></a>
<FONT color="green">042</FONT>       *  @serial          */<a name="line.42"></a>
<FONT color="green">043</FONT>      private final ArrayList freeStack;<a name="line.43"></a>
<FONT color="green">044</FONT>    <a name="line.44"></a>
<FONT color="green">045</FONT>      /**<a name="line.45"></a>
<FONT color="green">046</FONT>       * Constructor ObjectPool<a name="line.46"></a>
<FONT color="green">047</FONT>       *<a name="line.47"></a>
<FONT color="green">048</FONT>       * @param type Type of objects for this pool<a name="line.48"></a>
<FONT color="green">049</FONT>       */<a name="line.49"></a>
<FONT color="green">050</FONT>      public ObjectPool(Class type)<a name="line.50"></a>
<FONT color="green">051</FONT>      {<a name="line.51"></a>
<FONT color="green">052</FONT>        objectType = type;<a name="line.52"></a>
<FONT color="green">053</FONT>        freeStack = new ArrayList();<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>       * Constructor ObjectPool<a name="line.57"></a>
<FONT color="green">058</FONT>       *<a name="line.58"></a>
<FONT color="green">059</FONT>       * @param className Fully qualified name of the type of objects for this pool.<a name="line.59"></a>
<FONT color="green">060</FONT>       */<a name="line.60"></a>
<FONT color="green">061</FONT>      public ObjectPool(String className)<a name="line.61"></a>
<FONT color="green">062</FONT>      {<a name="line.62"></a>
<FONT color="green">063</FONT>        try<a name="line.63"></a>
<FONT color="green">064</FONT>        {<a name="line.64"></a>
<FONT color="green">065</FONT>          objectType = ObjectFactory.findProviderClass(<a name="line.65"></a>
<FONT color="green">066</FONT>            className, ObjectFactory.findClassLoader(), true);<a name="line.66"></a>
<FONT color="green">067</FONT>        }<a name="line.67"></a>
<FONT color="green">068</FONT>        catch(ClassNotFoundException cnfe)<a name="line.68"></a>
<FONT color="green">069</FONT>        {<a name="line.69"></a>
<FONT color="green">070</FONT>          throw new WrappedRuntimeException(cnfe);<a name="line.70"></a>
<FONT color="green">071</FONT>        }<a name="line.71"></a>
<FONT color="green">072</FONT>        freeStack = new ArrayList();<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>    <a name="line.75"></a>
<FONT color="green">076</FONT>      /**<a name="line.76"></a>
<FONT color="green">077</FONT>       * Constructor ObjectPool<a name="line.77"></a>
<FONT color="green">078</FONT>       *<a name="line.78"></a>
<FONT color="green">079</FONT>       *<a name="line.79"></a>
<FONT color="green">080</FONT>       * @param type Type of objects for this pool<a name="line.80"></a>
<FONT color="green">081</FONT>       * @param size Size of vector to allocate<a name="line.81"></a>
<FONT color="green">082</FONT>       */<a name="line.82"></a>
<FONT color="green">083</FONT>      public ObjectPool(Class type, int size)<a name="line.83"></a>
<FONT color="green">084</FONT>      {<a name="line.84"></a>
<FONT color="green">085</FONT>        objectType = type;<a name="line.85"></a>
<FONT color="green">086</FONT>        freeStack = new ArrayList(size);<a name="line.86"></a>
<FONT color="green">087</FONT>      }<a name="line.87"></a>
<FONT color="green">088</FONT>    <a name="line.88"></a>
<FONT color="green">089</FONT>      /**<a name="line.89"></a>
<FONT color="green">090</FONT>       * Constructor ObjectPool<a name="line.90"></a>
<FONT color="green">091</FONT>       *<a name="line.91"></a>
<FONT color="green">092</FONT>       */<a name="line.92"></a>
<FONT color="green">093</FONT>      public ObjectPool()<a name="line.93"></a>
<FONT color="green">094</FONT>      {<a name="line.94"></a>
<FONT color="green">095</FONT>        objectType = null;<a name="line.95"></a>
<FONT color="green">096</FONT>        freeStack = new ArrayList();<a name="line.96"></a>
<FONT color="green">097</FONT>      }<a name="line.97"></a>
<FONT color="green">098</FONT>    <a name="line.98"></a>
<FONT color="green">099</FONT>      /**<a name="line.99"></a>
<FONT color="green">100</FONT>       * Get an instance of the given object in this pool if available<a name="line.100"></a>
<FONT color="green">101</FONT>       *<a name="line.101"></a>
<FONT color="green">102</FONT>       *<a name="line.102"></a>
<FONT color="green">103</FONT>       * @return an instance of the given object if available or null<a name="line.103"></a>
<FONT color="green">104</FONT>       */<a name="line.104"></a>
<FONT color="green">105</FONT>      public synchronized Object getInstanceIfFree()<a name="line.105"></a>
<FONT color="green">106</FONT>      {<a name="line.106"></a>
<FONT color="green">107</FONT>    <a name="line.107"></a>
<FONT color="green">108</FONT>        // Check if the pool is empty.<a name="line.108"></a>
<FONT color="green">109</FONT>        if (!freeStack.isEmpty())<a name="line.109"></a>
<FONT color="green">110</FONT>        {<a name="line.110"></a>
<FONT color="green">111</FONT>    <a name="line.111"></a>
<FONT color="green">112</FONT>          // Remove object from end of free pool.<a name="line.112"></a>
<FONT color="green">113</FONT>          Object result = freeStack.remove(freeStack.size() - 1);<a name="line.113"></a>
<FONT color="green">114</FONT>          return result;<a name="line.114"></a>
<FONT color="green">115</FONT>        }<a name="line.115"></a>
<FONT color="green">116</FONT>    <a name="line.116"></a>
<FONT color="green">117</FONT>        return null;<a name="line.117"></a>
<FONT color="green">118</FONT>      }<a name="line.118"></a>
<FONT color="green">119</FONT>    <a name="line.119"></a>
<FONT color="green">120</FONT>      /**<a name="line.120"></a>
<FONT color="green">121</FONT>       * Get an instance of the given object in this pool <a name="line.121"></a>
<FONT color="green">122</FONT>       *<a name="line.122"></a>
<FONT color="green">123</FONT>       *<a name="line.123"></a>
<FONT color="green">124</FONT>       * @return An instance of the given object<a name="line.124"></a>
<FONT color="green">125</FONT>       */<a name="line.125"></a>
<FONT color="green">126</FONT>      public synchronized Object getInstance()<a name="line.126"></a>
<FONT color="green">127</FONT>      {<a name="line.127"></a>
<FONT color="green">128</FONT>    <a name="line.128"></a>
<FONT color="green">129</FONT>        // Check if the pool is empty.<a name="line.129"></a>
<FONT color="green">130</FONT>        if (freeStack.isEmpty())<a name="line.130"></a>
<FONT color="green">131</FONT>        {<a name="line.131"></a>
<FONT color="green">132</FONT>    <a name="line.132"></a>
<FONT color="green">133</FONT>          // Create a new object if so.<a name="line.133"></a>
<FONT color="green">134</FONT>          try<a name="line.134"></a>
<FONT color="green">135</FONT>          {<a name="line.135"></a>
<FONT color="green">136</FONT>            return objectType.newInstance();<a name="line.136"></a>
<FONT color="green">137</FONT>          }<a name="line.137"></a>
<FONT color="green">138</FONT>          catch (InstantiationException ex){}<a name="line.138"></a>
<FONT color="green">139</FONT>          catch (IllegalAccessException ex){}<a name="line.139"></a>
<FONT color="green">140</FONT>    <a name="line.140"></a>
<FONT color="green">141</FONT>          // Throw unchecked exception for error in pool configuration.<a name="line.141"></a>
<FONT color="green">142</FONT>          throw new RuntimeException(XMLMessages.createXMLMessage(XMLErrorResources.ER_EXCEPTION_CREATING_POOL, null)); //"exception creating new instance for pool");<a name="line.142"></a>
<FONT color="green">143</FONT>        }<a name="line.143"></a>
<FONT color="green">144</FONT>        else<a name="line.144"></a>
<FONT color="green">145</FONT>        {<a name="line.145"></a>
<FONT color="green">146</FONT>    <a name="line.146"></a>
<FONT color="green">147</FONT>          // Remove object from end of free pool.<a name="line.147"></a>
<FONT color="green">148</FONT>          Object result = freeStack.remove(freeStack.size() - 1);<a name="line.148"></a>
<FONT color="green">149</FONT>    <a name="line.149"></a>
<FONT color="green">150</FONT>          return result;<a name="line.150"></a>
<FONT color="green">151</FONT>        }<a name="line.151"></a>
<FONT color="green">152</FONT>      }<a name="line.152"></a>
<FONT color="green">153</FONT>    <a name="line.153"></a>
<FONT color="green">154</FONT>      /**<a name="line.154"></a>
<FONT color="green">155</FONT>       * Add an instance of the given object to the pool  <a name="line.155"></a>
<FONT color="green">156</FONT>       *<a name="line.156"></a>
<FONT color="green">157</FONT>       *<a name="line.157"></a>
<FONT color="green">158</FONT>       * @param obj Object to add.<a name="line.158"></a>
<FONT color="green">159</FONT>       */<a name="line.159"></a>
<FONT color="green">160</FONT>      public synchronized void freeInstance(Object obj)<a name="line.160"></a>
<FONT color="green">161</FONT>      {<a name="line.161"></a>
<FONT color="green">162</FONT>    <a name="line.162"></a>
<FONT color="green">163</FONT>        // Make sure the object is of the correct type.<a name="line.163"></a>
<FONT color="green">164</FONT>        // Remove safety.  -sb<a name="line.164"></a>
<FONT color="green">165</FONT>        // if (objectType.isInstance(obj))<a name="line.165"></a>
<FONT color="green">166</FONT>        // {<a name="line.166"></a>
<FONT color="green">167</FONT>        freeStack.add(obj);<a name="line.167"></a>
<FONT color="green">168</FONT>        // }<a name="line.168"></a>
<FONT color="green">169</FONT>        // else<a name="line.169"></a>
<FONT color="green">170</FONT>        // {<a name="line.170"></a>
<FONT color="green">171</FONT>        //  throw new IllegalArgumentException("argument type invalid for pool");<a name="line.171"></a>
<FONT color="green">172</FONT>        // }<a name="line.172"></a>
<FONT color="green">173</FONT>      }<a name="line.173"></a>
<FONT color="green">174</FONT>    }<a name="line.174"></a>


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