| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.pig; |
| |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Modifier; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.commons.logging.Log; |
| import org.apache.commons.logging.LogFactory; |
| import org.apache.pig.classification.InterfaceAudience; |
| import org.apache.pig.classification.InterfaceStability; |
| |
| /** |
| * This class is used to manage JVM Reuse in case of execution engines like Tez |
| * and Spark. |
| * |
| * Static data members of a UDF, LoadFunc or StoreFunc class |
| * need to be reset or object references made null or reinitialized |
| * when the jvm container is reused for new tasks. |
| * |
| * Example usage to perform static data cleanup in a UDF as follows. |
| * |
| * public class MyUDF extends EvalFunc<Tuple> { |
| * private static int numInvocations = 0; |
| * private static Reporter reporter; |
| * |
| * static { |
| * // Register this class for static data cleanup |
| * JVMReuseManager.getInstance().registerForStaticDataCleanup(MyUDF.class); |
| * } |
| * |
| * // Write a public static method that performs the cleanup |
| * // and annotate it with @StaticDataCleanup |
| * @StaticDataCleanup |
| * public static void staticDataCleanup() { |
| * numInvocations = 0; |
| * reporter = null; |
| * } |
| * #### UDF Code goes here ###### |
| * } |
| * |
| * @since Pig 0.14 |
| */ |
| @InterfaceAudience.Public |
| @InterfaceStability.Stable |
| public class JVMReuseManager { |
| |
| private static Log LOG = LogFactory.getLog(JVMReuseImpl.class); |
| private List<Method> cleanupMethods = new ArrayList<Method>(); |
| private static JVMReuseManager instance = new JVMReuseManager(); |
| |
| private JVMReuseManager() { |
| } |
| |
| public static JVMReuseManager getInstance() { |
| return instance; |
| } |
| |
| public void registerForStaticDataCleanup(Class<?> clazz) { |
| for (Method method : clazz.getMethods()) { |
| if (method.isAnnotationPresent(StaticDataCleanup.class)) { |
| if (!(Modifier.isStatic(method.getModifiers()) |
| && Modifier.isPublic(method.getModifiers()))) { |
| throw new RuntimeException( |
| "Method " + method.getName() + " in class " + clazz.getName() + |
| "should be public and static as it is annotated with "); |
| } |
| LOG.debug("Method " + method.getName() + " in class " |
| + method.getDeclaringClass() |
| + " registered for static data cleanup"); |
| instance.cleanupMethods.add(method); |
| } |
| } |
| } |
| |
| List<Method> getStaticDataCleanupMethods() { |
| return cleanupMethods; |
| } |
| |
| } |