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| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.util;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import edu.umd.cs.findbugs.annotations.Nullable;</span> |
| <span class="source-line-no">021</span><span id="line-21">import java.util.concurrent.ConcurrentHashMap;</span> |
| <span class="source-line-no">022</span><span id="line-22">import java.util.concurrent.ConcurrentMap;</span> |
| <span class="source-line-no">023</span><span id="line-23">import java.util.concurrent.TimeUnit;</span> |
| <span class="source-line-no">024</span><span id="line-24">import java.util.function.Function;</span> |
| <span class="source-line-no">025</span><span id="line-25">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">026</span><span id="line-26">import org.slf4j.Logger;</span> |
| <span class="source-line-no">027</span><span id="line-27">import org.slf4j.LoggerFactory;</span> |
| <span class="source-line-no">028</span><span id="line-28"></span> |
| <span class="source-line-no">029</span><span id="line-29">/**</span> |
| <span class="source-line-no">030</span><span id="line-30"> * Cache to hold resolved Functions of a specific signature, generated through reflection. These can</span> |
| <span class="source-line-no">031</span><span id="line-31"> * be (relatively) costly to create, but then are much faster than typical Method.invoke calls when</span> |
| <span class="source-line-no">032</span><span id="line-32"> * executing. The cache is built-up on demand as calls are made to new classes. The functions are</span> |
| <span class="source-line-no">033</span><span id="line-33"> * cached for the lifetime of the process. If a function cannot be created (security reasons, method</span> |
| <span class="source-line-no">034</span><span id="line-34"> * not found, etc), a fallback function is cached which always returns null. Callers to</span> |
| <span class="source-line-no">035</span><span id="line-35"> * {@link #getAndCallByName(String, Object)} should have handling for null return values.</span> |
| <span class="source-line-no">036</span><span id="line-36"> * <p></span> |
| <span class="source-line-no">037</span><span id="line-37"> * An instance is created for a specified baseClass (i.e. Filter), argClass (i.e. byte[]), and</span> |
| <span class="source-line-no">038</span><span id="line-38"> * static methodName to call. These are used to resolve a Function which delegates to that static</span> |
| <span class="source-line-no">039</span><span id="line-39"> * method, if it is found.</span> |
| <span class="source-line-no">040</span><span id="line-40"> * @param <I> the input argument type for the resolved functions</span> |
| <span class="source-line-no">041</span><span id="line-41"> * @param <R> the return type for the resolved functions</span> |
| <span class="source-line-no">042</span><span id="line-42"> */</span> |
| <span class="source-line-no">043</span><span id="line-43">@InterfaceAudience.Private</span> |
| <span class="source-line-no">044</span><span id="line-44">public final class ReflectedFunctionCache<I, R> {</span> |
| <span class="source-line-no">045</span><span id="line-45"></span> |
| <span class="source-line-no">046</span><span id="line-46"> private static final Logger LOG = LoggerFactory.getLogger(ReflectedFunctionCache.class);</span> |
| <span class="source-line-no">047</span><span id="line-47"></span> |
| <span class="source-line-no">048</span><span id="line-48"> private final ConcurrentMap<String, Function<I, ? extends R>> lambdasByClass =</span> |
| <span class="source-line-no">049</span><span id="line-49"> new ConcurrentHashMap<>();</span> |
| <span class="source-line-no">050</span><span id="line-50"> private final Class<R> baseClass;</span> |
| <span class="source-line-no">051</span><span id="line-51"> private final Class<I> argClass;</span> |
| <span class="source-line-no">052</span><span id="line-52"> private final String methodName;</span> |
| <span class="source-line-no">053</span><span id="line-53"> private final ClassLoader classLoader;</span> |
| <span class="source-line-no">054</span><span id="line-54"></span> |
| <span class="source-line-no">055</span><span id="line-55"> public ReflectedFunctionCache(Class<R> baseClass, Class<I> argClass, String staticMethodName) {</span> |
| <span class="source-line-no">056</span><span id="line-56"> this.classLoader = getClass().getClassLoader();</span> |
| <span class="source-line-no">057</span><span id="line-57"> this.baseClass = baseClass;</span> |
| <span class="source-line-no">058</span><span id="line-58"> this.argClass = argClass;</span> |
| <span class="source-line-no">059</span><span id="line-59"> this.methodName = staticMethodName;</span> |
| <span class="source-line-no">060</span><span id="line-60"> }</span> |
| <span class="source-line-no">061</span><span id="line-61"></span> |
| <span class="source-line-no">062</span><span id="line-62"> /**</span> |
| <span class="source-line-no">063</span><span id="line-63"> * Get and execute the Function for the given className, passing the argument to the function and</span> |
| <span class="source-line-no">064</span><span id="line-64"> * returning the result.</span> |
| <span class="source-line-no">065</span><span id="line-65"> * @param className the full name of the class to lookup</span> |
| <span class="source-line-no">066</span><span id="line-66"> * @param argument the argument to pass to the function, if found.</span> |
| <span class="source-line-no">067</span><span id="line-67"> * @return null if a function is not found for classname, otherwise the result of the function.</span> |
| <span class="source-line-no">068</span><span id="line-68"> */</span> |
| <span class="source-line-no">069</span><span id="line-69"> @Nullable</span> |
| <span class="source-line-no">070</span><span id="line-70"> public R getAndCallByName(String className, I argument) {</span> |
| <span class="source-line-no">071</span><span id="line-71"> // todo: if we ever make java9+ our lowest supported jdk version, we can</span> |
| <span class="source-line-no">072</span><span id="line-72"> // handle generating these for newly loaded classes from our DynamicClassLoader using</span> |
| <span class="source-line-no">073</span><span id="line-73"> // MethodHandles.privateLookupIn(). For now this is not possible, because we can't easily</span> |
| <span class="source-line-no">074</span><span id="line-74"> // create a privileged lookup in a non-default ClassLoader. So while this cache loads</span> |
| <span class="source-line-no">075</span><span id="line-75"> // over time, it will never load a custom filter from "hbase.dynamic.jars.dir".</span> |
| <span class="source-line-no">076</span><span id="line-76"> Function<I, ? extends R> lambda =</span> |
| <span class="source-line-no">077</span><span id="line-77"> ConcurrentMapUtils.computeIfAbsent(lambdasByClass, className, () -> loadFunction(className));</span> |
| <span class="source-line-no">078</span><span id="line-78"></span> |
| <span class="source-line-no">079</span><span id="line-79"> return lambda.apply(argument);</span> |
| <span class="source-line-no">080</span><span id="line-80"> }</span> |
| <span class="source-line-no">081</span><span id="line-81"></span> |
| <span class="source-line-no">082</span><span id="line-82"> private Function<I, ? extends R> loadFunction(String className) {</span> |
| <span class="source-line-no">083</span><span id="line-83"> long startTime = System.nanoTime();</span> |
| <span class="source-line-no">084</span><span id="line-84"> try {</span> |
| <span class="source-line-no">085</span><span id="line-85"> Class<?> clazz = Class.forName(className, false, classLoader);</span> |
| <span class="source-line-no">086</span><span id="line-86"> if (!baseClass.isAssignableFrom(clazz)) {</span> |
| <span class="source-line-no">087</span><span id="line-87"> LOG.debug("Requested class {} is not assignable to {}, skipping creation of function",</span> |
| <span class="source-line-no">088</span><span id="line-88"> className, baseClass.getName());</span> |
| <span class="source-line-no">089</span><span id="line-89"> return this::notFound;</span> |
| <span class="source-line-no">090</span><span id="line-90"> }</span> |
| <span class="source-line-no">091</span><span id="line-91"> return ReflectionUtils.getOneArgStaticMethodAsFunction(clazz, methodName, argClass,</span> |
| <span class="source-line-no">092</span><span id="line-92"> (Class<? extends R>) clazz);</span> |
| <span class="source-line-no">093</span><span id="line-93"> } catch (Throwable t) {</span> |
| <span class="source-line-no">094</span><span id="line-94"> LOG.debug("Failed to create function for {}", className, t);</span> |
| <span class="source-line-no">095</span><span id="line-95"> return this::notFound;</span> |
| <span class="source-line-no">096</span><span id="line-96"> } finally {</span> |
| <span class="source-line-no">097</span><span id="line-97"> LOG.debug("Populated cache for {} in {}ms", className,</span> |
| <span class="source-line-no">098</span><span id="line-98"> TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime));</span> |
| <span class="source-line-no">099</span><span id="line-99"> }</span> |
| <span class="source-line-no">100</span><span id="line-100"> }</span> |
| <span class="source-line-no">101</span><span id="line-101"></span> |
| <span class="source-line-no">102</span><span id="line-102"> /**</span> |
| <span class="source-line-no">103</span><span id="line-103"> * In order to use computeIfAbsent, we can't store nulls in our cache. So we store a lambda which</span> |
| <span class="source-line-no">104</span><span id="line-104"> * resolves to null. The contract is that getAndCallByName returns null in this case.</span> |
| <span class="source-line-no">105</span><span id="line-105"> */</span> |
| <span class="source-line-no">106</span><span id="line-106"> private R notFound(I argument) {</span> |
| <span class="source-line-no">107</span><span id="line-107"> return null;</span> |
| <span class="source-line-no">108</span><span id="line-108"> }</span> |
| <span class="source-line-no">109</span><span id="line-109"></span> |
| <span class="source-line-no">110</span><span id="line-110">}</span> |
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| </pre> |
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