Terminator.java

/*
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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * 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.
 *
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package java.lang;

import sun.misc.Signal;
import sun.misc.SignalHandler;


/**
 * Package-private utility class for setting up and tearing down
 * platform-specific support for termination-triggered shutdowns.
 *
 * @author   Mark Reinhold
 * @since    1.3
 */

class Terminator {

    private static SignalHandler handler = null;

    /* Invocations of setup and teardown are already synchronized
     * on the shutdown lock, so no further synchronization is needed here
     */

    static void setup() {
        if (handler != null) return;
        SignalHandler sh = new SignalHandler() {
            public void handle(Signal sig) {
                Shutdown.exit(sig.getNumber() + 0200);
            }
        };
        handler = sh;
        // When -Xrs is specified the user is responsible for
        // ensuring that shutdown hooks are run by calling
        // System.exit()
        try {
            Signal.handle(new Signal("HUP"), sh);
        } catch (IllegalArgumentException e) {
        }
        try {
            Signal.handle(new Signal("INT"), sh);
        } catch (IllegalArgumentException e) {
        }
        try {
            Signal.handle(new Signal("TERM"), sh);
        } catch (IllegalArgumentException e) {
        }
    }

    static void teardown() {
        /* The current sun.misc.Signal class does not support
         * the cancellation of handlers
         */
    }

}