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 /** 28 * This is a combination of ThreadControllerWrapper's inner class SafeThread 29 * that was introduced as a fix for CR 6607339 30 * and sun.misc.ManagedLocalsThread, a thread that has it's thread locals, and 31 * inheritable thread locals erased on construction. Except the run method, 32 * it is identical to sun.misc.ManagedLocalsThread. 33 */ 34 public class SafeThread extends Thread { 35 36 private static final jdk.internal.misc.Unsafe UNSAFE; 37 private static final long THREAD_LOCALS; 38 private static final long INHERITABLE_THREAD_LOCALS; 39 40 private volatile boolean ran = false; 41 42 public SafeThread(Runnable target) { 43 super(target); 44 eraseThreadLocals(); 45 } 46 47 public SafeThread(Runnable target, String name) { 48 super(target, name); 49 eraseThreadLocals(); 50 } 51 52 public SafeThread(ThreadGroup group, Runnable target, String name) { 53 super(group, target, name); 54 eraseThreadLocals(); 55 } 56 57 public final void run() { 58 if (Thread.currentThread() != this) { 59 throw new IllegalStateException("The run() method in a" 60 + " SafeThread cannot be called from another thread."); 61 } 62 synchronized (this) { 63 if (!ran) { 64 ran = true; 65 } else { 66 throw new IllegalStateException("The run() method in a" 67 + " SafeThread cannot be called more than once."); 68 } 69 } 70 super.run(); 71 } 72 73 /** 74 * Drops all thread locals (and inherited thread locals). 75 */ 76 public final void eraseThreadLocals() { 77 UNSAFE.putReference(this, THREAD_LOCALS, null); 78 UNSAFE.putReference(this, INHERITABLE_THREAD_LOCALS, null); 79 } 80 81 static { 82 UNSAFE = jdk.internal.misc.Unsafe.getUnsafe(); 83 Class<?> t = Thread.class; 84 try { 85 THREAD_LOCALS = UNSAFE.objectFieldOffset(t.getDeclaredField("threadLocals")); 86 INHERITABLE_THREAD_LOCALS = UNSAFE.objectFieldOffset(t.getDeclaredField("inheritableThreadLocals")); 87 } catch (Exception e) { 88 throw new Error(e); 89 } 90 } 91 92 }