1 /* 2 * Copyright (c) 2013, 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 26 package sun.misc; 27 28 import java.util.concurrent.locks.ReentrantLock; 29 30 /** 31 * This class is used to prevent multiple calling of g_thread_init (). 32 * 33 * Since version 2.24 of GLib, calling g_thread_init () multiple times is 34 * allowed, but for older versions it will crash. There are two ways to 35 * find out if g_thread_init() has been called: 36 * g_thread_get_initialized (), but it was introduced in 2.20 37 * g_thread_supported (), but it is a macro and cannot be loaded with dlsym. 38 * 39 * usage: 40 * <pre> 41 * lock(); 42 * if (isInitializationNeeded) { 43 * //call to g_thread_init(); 44 * initFinished(); 45 * } 46 * unlock(); 47 * </pre> 48 */ 49 public final class GThreadHelper { 50 51 private static final ReentrantLock LOCK = new ReentrantLock(); 52 private static volatile boolean isGThreadInitialized = false; 53 54 static void lock() { 55 LOCK.lock(); 56 } 57 58 static void unlock() { 59 LOCK.unlock(); 60 } 61 62 /** 63 * MUST be called under LOCK 64 * @return {@code true} if g_thread_init() has not been called 65 */ 66 static boolean isInitializationNeeded() { 67 return !isGThreadInitialized; 68 } 69 70 /** 71 * MUST be called under LOCK 72 * Call this method only after g_thread_init() call. 73 */ 74 static void initFinished() { 75 isGThreadInitialized = true; 76 } 77 }