J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2006 Sun Microsystems, Inc. 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. |
| 8 | * |
| 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| 13 | * accompanied this code). |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License version |
| 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 18 | * |
| 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 21 | * have any questions. |
| 22 | */ |
| 23 | |
| 24 | /* |
| 25 | * @test |
| 26 | * @bug 6387919 |
| 27 | * @summary Confirm ThreadLocal.set() usage is not a side effect of get() |
| 28 | * @author Pete Soper |
| 29 | */ |
| 30 | public class ImmutableLocal |
| 31 | { |
| 32 | /** |
| 33 | * {@link ThreadLocal} guaranteed to always return the same reference. |
| 34 | */ |
| 35 | abstract public static class ImmutableThreadLocal extends ThreadLocal { |
| 36 | public void set(final Object value) { |
| 37 | throw new RuntimeException("ImmutableThreadLocal set called"); |
| 38 | } |
| 39 | |
| 40 | // force override |
| 41 | abstract protected Object initialValue(); |
| 42 | } |
| 43 | |
| 44 | private static final ThreadLocal cache = new ImmutableThreadLocal() { |
| 45 | public Object initialValue() { |
| 46 | return Thread.currentThread().getName(); |
| 47 | } |
| 48 | }; |
| 49 | |
| 50 | public static void main(final String[] args) { |
| 51 | System.out.println("cache.get() = " + cache.get()); |
| 52 | } |
| 53 | } |