| /* |
| * 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.geode.distributed.internal.deadlock; |
| |
| import java.lang.reflect.Field; |
| import java.lang.reflect.InvocationTargetException; |
| import java.lang.reflect.Method; |
| |
| /** |
| * Most of this thread local is safe to use, except for the getValue(Thread) method. That is not |
| * guaranteed to be correct. But for our deadlock detection tool I think it's good enough, and this |
| * class provides a very low overhead way for us to record what thread holds a particular resource. |
| * |
| * |
| */ |
| public class UnsafeThreadLocal<T> extends ThreadLocal<T> { |
| /** |
| * Dangerous method. Uses reflection to extract the thread local for a given thread. |
| * |
| * Unlike get(), this method does not set the initial value if none is found |
| * |
| */ |
| public T get(Thread thread) { |
| return (T) get(this, thread); |
| } |
| |
| private static Object get(ThreadLocal threadLocal, Thread thread) { |
| try { |
| Object threadLocalMap = |
| invokePrivate(threadLocal, "getMap", new Class[] {Thread.class}, new Object[] {thread}); |
| |
| if (threadLocalMap != null) { |
| Object entry = invokePrivate(threadLocalMap, "getEntry", new Class[] {ThreadLocal.class}, |
| new Object[] {threadLocal}); |
| if (entry != null) |
| return getPrivate(entry, "value"); |
| } |
| return null; |
| } catch (Exception e) { |
| throw new RuntimeException("Unable to extract thread local", e); |
| } |
| } |
| |
| private static Object getPrivate(Object object, String fieldName) throws SecurityException, |
| NoSuchFieldException, IllegalArgumentException, IllegalAccessException { |
| Field field = object.getClass().getDeclaredField(fieldName); |
| field.setAccessible(true); |
| return field.get(object); |
| } |
| |
| private static Object invokePrivate(Object object, String methodName, Class[] argTypes, |
| Object[] args) throws SecurityException, NoSuchMethodException, IllegalArgumentException, |
| IllegalAccessException, InvocationTargetException { |
| |
| Method method = null; |
| Class clazz = object.getClass(); |
| while (method == null) { |
| try { |
| method = clazz.getDeclaredMethod(methodName, argTypes); |
| } catch (NoSuchMethodException e) { |
| clazz = clazz.getSuperclass(); |
| if (clazz == null) { |
| throw e; |
| } |
| } |
| } |
| method.setAccessible(true); |
| Object result = method.invoke(object, args); |
| return result; |
| } |
| |
| } |