/*
 * Copyright (c) 2012, 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 sun.lwawt.macosx;

import sun.awt.AWTAutoShutdown;

/**
 * Support class for keeping AWT alive when it's embedded in another toolkit.
 * This is done by sending a dummy native event to the native event loop.
 */
final class AWTKeepAlive extends Thread {
    private final static AWTKeepAlive theInstance = new AWTKeepAlive();
    static {
        theInstance.setName("AWTKeepAlive");
        theInstance.setDaemon(true);
    }

    /**
     * An interval for sending pings.
     *
     * Generally, it must be twice as less than the SAFETY_TIMEOUT
     * in an auto-shutdown machinery of the mebedder's toolkit.
     * Both AWT and FX use 1000 ms safety interval currently.
     */
    private static final int PING_TIMEOUT = 500;

    /**
     * Activate the AWTKeepAlive thread.
     */
    public static void activate() {
        theInstance.start();
    }

    @Override
    public void run() {
        try {
            do {
                if (!AWTAutoShutdown.getInstance().isReadyToShutdown()) {
                    // Send a dummy native event
                    LWCToolkit.getLWCToolkit().syncNativeQueue(1);
                }
                Thread.sleep(PING_TIMEOUT);
            } while (true);
        } catch (InterruptedException ex) {
        }
    }
}