1 /* 2 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 package com.sun.org.apache.xml.internal.utils; 26 27 import sun.misc.Unsafe; 28 29 /** 30 * This is a combination of ThreadControllerWrapper's inner class SafeThread 31 * that was introduced as a fix for CR 6607339 32 * and sun.misc.ManagedLocalsThread, a thread that has it's thread locals, and 33 * inheritable thread locals erased on construction. Except the run method, 34 * it is identical to sun.misc.ManagedLocalsThread. 35 */ 36 public class SafeThread extends Thread { 37 38 private static final Unsafe UNSAFE; 39 private static final long THREAD_LOCALS; 40 private static final long INHERITABLE_THREAD_LOCALS; 41 42 private volatile boolean ran = false; 43 44 public SafeThread(Runnable target) { 45 super(target); 46 eraseThreadLocals(); 47 } 48 49 public SafeThread(Runnable target, String name) { 50 super(target, name); 51 eraseThreadLocals(); 52 } 53 54 public SafeThread(ThreadGroup group, Runnable target, String name) { 55 super(group, target, name); 56 eraseThreadLocals(); 57 } 58 59 public final void run() { 60 if (Thread.currentThread() != this) { 61 throw new IllegalStateException("The run() method in a" 62 + " SafeThread cannot be called from another thread."); 63 } 64 synchronized (this) { 65 if (!ran) { 66 ran = true; 67 } else { 68 throw new IllegalStateException("The run() method in a" 69 + " SafeThread cannot be called more than once."); 70 } 71 } 72 super.run(); 73 } 74 75 /** 76 * Drops all thread locals (and inherited thread locals). 77 */ 78 public final void eraseThreadLocals() { 79 UNSAFE.putObject(this, THREAD_LOCALS, null); 80 UNSAFE.putObject(this, INHERITABLE_THREAD_LOCALS, null); 81 } 82 83 static { 84 UNSAFE = Unsafe.getUnsafe(); 85 Class<?> t = Thread.class; 86 try { 87 THREAD_LOCALS = UNSAFE.objectFieldOffset(t.getDeclaredField("threadLocals")); 88 INHERITABLE_THREAD_LOCALS = UNSAFE.objectFieldOffset(t.getDeclaredField("inheritableThreadLocals")); 89 } catch (Exception e) { 90 throw new Error(e); 91 } 92 } 93 94 }