1 /* 2 * Copyright (c) 2016, 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 jdk.internal.ref; 27 28 import jdk.internal.misc.InnocuousThread; 29 30 import java.security.AccessController; 31 import java.security.PrivilegedAction; 32 import java.util.concurrent.ThreadFactory; 33 34 /** 35 * CleanerFactory provides a Cleaner for use within system modules. 36 * The cleaner is created on the first reference to the CleanerFactory. 37 */ 38 public final class CleanerFactory { 39 40 /* The common Cleaner. */ 41 private final static ExtendedCleaner commonCleaner = ExtendedCleaner.create( 42 new ThreadFactory() { 43 @Override 44 public Thread newThread(Runnable r) { 45 return AccessController.doPrivileged(new PrivilegedAction<>() { 46 @Override 47 public Thread run() { 48 Thread t = InnocuousThread.newSystemThread("Common-Cleaner", r); 49 t.setPriority(Thread.MAX_PRIORITY - 2); 50 return t; 51 } 52 }); 53 } 54 } 55 ); 56 57 /** 58 * ExtendedCleaner for use within system modules. 59 * <p> 60 * This Cleaner's cleaning loop will run on a thread whose context 61 * class loader is {@code null}. The system cleaning action to perform in 62 * this Cleaner should handle a {@code null} context class loader. 63 * <p> 64 * This Cleaner is an {@link ExtendedCleaner} which supports helping 65 * the cleaner thread from arbitrary application threads. The system cleaning 66 * action to perform in this Cleaner should also handle being executed by 67 * arbitrary application thread. 68 * 69 * @return an ExtendedCleaner for use within system modules 70 */ 71 public static ExtendedCleaner cleaner() { 72 return commonCleaner; 73 } 74 }