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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.internal;<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.SystemEnv.*;<a name="line.15"></a> |
| <span class="sourceLineNo">016</span>import java.util.concurrent.*;<a name="line.16"></a> |
| <span class="sourceLineNo">017</span>import java.util.concurrent.atomic.*;<a name="line.17"></a> |
| <span class="sourceLineNo">018</span>import java.util.function.*;<a name="line.18"></a> |
| <span class="sourceLineNo">019</span><a name="line.19"></a> |
| <span class="sourceLineNo">020</span>/**<a name="line.20"></a> |
| <span class="sourceLineNo">021</span> * Simple in-memory cache of objects.<a name="line.21"></a> |
| <span class="sourceLineNo">022</span> *<a name="line.22"></a> |
| <span class="sourceLineNo">023</span> * <p><a name="line.23"></a> |
| <span class="sourceLineNo">024</span> * Essentially just a wrapper around a ConcurrentHashMap.<a name="line.24"></a> |
| <span class="sourceLineNo">025</span> *<a name="line.25"></a> |
| <span class="sourceLineNo">026</span> * <ul class='seealso'><a name="line.26"></a> |
| <span class="sourceLineNo">027</span> * <li class='extlink'>{@source}<a name="line.27"></a> |
| <span class="sourceLineNo">028</span> * </ul><a name="line.28"></a> |
| <span class="sourceLineNo">029</span> *<a name="line.29"></a> |
| <span class="sourceLineNo">030</span> * @param <K> The key type.<a name="line.30"></a> |
| <span class="sourceLineNo">031</span> * @param <V> The value type.<a name="line.31"></a> |
| <span class="sourceLineNo">032</span> */<a name="line.32"></a> |
| <span class="sourceLineNo">033</span>public class Cache<K,V> {<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> // Static<a name="line.36"></a> |
| <span class="sourceLineNo">037</span> //-----------------------------------------------------------------------------------------------------------------<a name="line.37"></a> |
| <span class="sourceLineNo">038</span><a name="line.38"></a> |
| <span class="sourceLineNo">039</span> /**<a name="line.39"></a> |
| <span class="sourceLineNo">040</span> * Static creator.<a name="line.40"></a> |
| <span class="sourceLineNo">041</span> *<a name="line.41"></a> |
| <span class="sourceLineNo">042</span> * @param <K> The key type.<a name="line.42"></a> |
| <span class="sourceLineNo">043</span> * @param <V> The value type.<a name="line.43"></a> |
| <span class="sourceLineNo">044</span> * @param key The key type.<a name="line.44"></a> |
| <span class="sourceLineNo">045</span> * @param type The value type.<a name="line.45"></a> |
| <span class="sourceLineNo">046</span> * @return A new builder for this object.<a name="line.46"></a> |
| <span class="sourceLineNo">047</span> */<a name="line.47"></a> |
| <span class="sourceLineNo">048</span> public static <K,V> Builder<K,V> of(Class<K> key, Class<V> type) {<a name="line.48"></a> |
| <span class="sourceLineNo">049</span> return new Builder<>(type);<a name="line.49"></a> |
| <span class="sourceLineNo">050</span> }<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> // Builder<a name="line.53"></a> |
| <span class="sourceLineNo">054</span> //-----------------------------------------------------------------------------------------------------------------<a name="line.54"></a> |
| <span class="sourceLineNo">055</span><a name="line.55"></a> |
| <span class="sourceLineNo">056</span> /**<a name="line.56"></a> |
| <span class="sourceLineNo">057</span> * Builder class.<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> *<a name="line.58"></a> |
| <span class="sourceLineNo">059</span> * @param <K> The key type.<a name="line.59"></a> |
| <span class="sourceLineNo">060</span> * @param <V> The value type.<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> */<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> public static class Builder<K,V> {<a name="line.62"></a> |
| <span class="sourceLineNo">063</span> boolean disabled, logOnExit;<a name="line.63"></a> |
| <span class="sourceLineNo">064</span> int maxSize;<a name="line.64"></a> |
| <span class="sourceLineNo">065</span> Class<V> type;<a name="line.65"></a> |
| <span class="sourceLineNo">066</span><a name="line.66"></a> |
| <span class="sourceLineNo">067</span> Builder(Class<V> type) {<a name="line.67"></a> |
| <span class="sourceLineNo">068</span> this.type = type;<a name="line.68"></a> |
| <span class="sourceLineNo">069</span> disabled = env("juneau.cache.disable", false);<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> maxSize = env("juneau.cache.maxSize", 1000);<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> logOnExit = env("juneau.cache.logOnExit", false);<a name="line.71"></a> |
| <span class="sourceLineNo">072</span> }<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> * Disables this cache.<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> *<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> * @return This object.<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> */<a name="line.78"></a> |
| <span class="sourceLineNo">079</span> public Builder<K,V> disabled() {<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> disabled = true;<a name="line.80"></a> |
| <span class="sourceLineNo">081</span> return this;<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> /**<a name="line.84"></a> |
| <span class="sourceLineNo">085</span> * When enabled, logs cache hit statistics on this cache.<a name="line.85"></a> |
| <span class="sourceLineNo">086</span> *<a name="line.86"></a> |
| <span class="sourceLineNo">087</span> * @return This object.<a name="line.87"></a> |
| <span class="sourceLineNo">088</span> */<a name="line.88"></a> |
| <span class="sourceLineNo">089</span> public Builder<K,V> logOnExit() {<a name="line.89"></a> |
| <span class="sourceLineNo">090</span> logOnExit = true;<a name="line.90"></a> |
| <span class="sourceLineNo">091</span> return this;<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> }<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> * Specifies the maximum size of this cache.<a name="line.95"></a> |
| <span class="sourceLineNo">096</span> *<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> * @param value The value for this setting.<a name="line.97"></a> |
| <span class="sourceLineNo">098</span> * @return This object.<a name="line.98"></a> |
| <span class="sourceLineNo">099</span> */<a name="line.99"></a> |
| <span class="sourceLineNo">100</span> public Builder<K,V> maxSize(int value) {<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> maxSize = value;<a name="line.101"></a> |
| <span class="sourceLineNo">102</span> return this;<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> * Builds this object.<a name="line.106"></a> |
| <span class="sourceLineNo">107</span> *<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> * @return A new cache.<a name="line.108"></a> |
| <span class="sourceLineNo">109</span> */<a name="line.109"></a> |
| <span class="sourceLineNo">110</span> public Cache<K,V> build() {<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> return new Cache<>(this);<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><a name="line.114"></a> |
| <span class="sourceLineNo">115</span> //-----------------------------------------------------------------------------------------------------------------<a name="line.115"></a> |
| <span class="sourceLineNo">116</span> // Instance<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> private final int maxSize;<a name="line.119"></a> |
| <span class="sourceLineNo">120</span> private final ConcurrentHashMap<K,V> cache;<a name="line.120"></a> |
| <span class="sourceLineNo">121</span> private final AtomicInteger cacheHits = new AtomicInteger();<a name="line.121"></a> |
| <span class="sourceLineNo">122</span><a name="line.122"></a> |
| <span class="sourceLineNo">123</span> /**<a name="line.123"></a> |
| <span class="sourceLineNo">124</span> * Constructor<a name="line.124"></a> |
| <span class="sourceLineNo">125</span> *<a name="line.125"></a> |
| <span class="sourceLineNo">126</span> * @param builder The builder for this object.<a name="line.126"></a> |
| <span class="sourceLineNo">127</span> */<a name="line.127"></a> |
| <span class="sourceLineNo">128</span> protected Cache(Builder<K,V> builder) {<a name="line.128"></a> |
| <span class="sourceLineNo">129</span> cache = builder.disabled ? null : new ConcurrentHashMap<>();<a name="line.129"></a> |
| <span class="sourceLineNo">130</span> maxSize = builder.maxSize;<a name="line.130"></a> |
| <span class="sourceLineNo">131</span> if (builder.logOnExit) {<a name="line.131"></a> |
| <span class="sourceLineNo">132</span> SystemUtils.shutdownMessage(()->builder.type.getSimpleName() + " cache: hits=" + cacheHits.get() + ", misses: " + cache.size());<a name="line.132"></a> |
| <span class="sourceLineNo">133</span> }<a name="line.133"></a> |
| <span class="sourceLineNo">134</span> }<a name="line.134"></a> |
| <span class="sourceLineNo">135</span> /**<a name="line.135"></a> |
| <span class="sourceLineNo">136</span> * Retrieves the value with the specified key from this cache.<a name="line.136"></a> |
| <span class="sourceLineNo">137</span> *<a name="line.137"></a> |
| <span class="sourceLineNo">138</span> * @param key The key.<a name="line.138"></a> |
| <span class="sourceLineNo">139</span> * @param supplier The supplier for creating this object if it's not found in the cache.<a name="line.139"></a> |
| <span class="sourceLineNo">140</span> * @return The value.<a name="line.140"></a> |
| <span class="sourceLineNo">141</span> */<a name="line.141"></a> |
| <span class="sourceLineNo">142</span> public V get(K key, Supplier<V> supplier) {<a name="line.142"></a> |
| <span class="sourceLineNo">143</span> if (cache == null || key == null)<a name="line.143"></a> |
| <span class="sourceLineNo">144</span> return supplier.get();<a name="line.144"></a> |
| <span class="sourceLineNo">145</span> V v = cache.get(key);<a name="line.145"></a> |
| <span class="sourceLineNo">146</span> if (v == null) {<a name="line.146"></a> |
| <span class="sourceLineNo">147</span> if (cache.size() > maxSize)<a name="line.147"></a> |
| <span class="sourceLineNo">148</span> cache.clear();<a name="line.148"></a> |
| <span class="sourceLineNo">149</span> v = supplier.get();<a name="line.149"></a> |
| <span class="sourceLineNo">150</span> cache.putIfAbsent(key, v);<a name="line.150"></a> |
| <span class="sourceLineNo">151</span> } else {<a name="line.151"></a> |
| <span class="sourceLineNo">152</span> cacheHits.incrementAndGet();<a name="line.152"></a> |
| <span class="sourceLineNo">153</span> }<a name="line.153"></a> |
| <span class="sourceLineNo">154</span> return v;<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> |
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| </pre> |
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