/*

 * Copyright (c) 2016, 2021, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package jdk.internal.ref;

import jdk.internal.misc.InnocuousThread;

import java.lang.ref.Cleaner;

import java.util.concurrent.ThreadFactory;

/**

 * CleanerFactory provides a Cleaner for use within system modules.

 * The cleaner is created on the first reference to the CleanerFactory.

 */

public final class CleanerFactory {

    /* The common Cleaner. */

    private static final Cleaner commonCleaner = Cleaner.create(new ThreadFactory() {

        @Override

        public Thread newThread(Runnable r) {

            return InnocuousThread.newSystemThread("Common-Cleaner",

                    r, Thread.MAX_PRIORITY - 2);

        }

    });

    /**

     * Cleaner for use within system modules.

     *

     * This Cleaner will run on a thread whose context class loader

     * is {@code null}. The system cleaning action to perform in

     * this Cleaner should handle a {@code null} context class loader.

     *

     * @return a Cleaner for use within system modules

     */

    public static Cleaner cleaner() {

        return commonCleaner;

    }

}