// ***************************************************************************************************************************
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
// * with the License.  You may obtain a copy of the License at                                                              *
// *                                                                                                                         *
// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
// *                                                                                                                         *
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// * specific language governing permissions and limitations under the License.                                              *
// ***************************************************************************************************************************
package org.apache.juneau.internal;

import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;

/**
 * System utilities.
 *
 * <ul class='seealso'>
 * 	<li class='extlink'>{@source}
 * </ul>
 */
public class SystemUtils {

	static final List<Supplier<String>> SHUTDOWN_MESSAGES = new CopyOnWriteArrayList<>();
	static {
		Runtime.getRuntime().addShutdownHook(new Thread() {
			@Override
			public void run() {
				if (! Boolean.getBoolean("SystemUtils.quiet"))
				SHUTDOWN_MESSAGES.forEach(x -> System.out.println(x.get()));
			}
		});
	}

	/**
	 * Adds a console message to display when the JVM shuts down.
	 *
	 * @param message The message to display.
	 */
	public static void shutdownMessage(Supplier<String> message) {
		SHUTDOWN_MESSAGES.add(message);
	}

}
