001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.common.internal;
014
015import java.util.*;
016import java.util.concurrent.*;
017import java.util.function.*;
018
019/**
020 * System utilities.
021 */
022public class SystemUtils {
023
024   static final List<Supplier<String>> SHUTDOWN_MESSAGES = new CopyOnWriteArrayList<>();
025   static {
026      Runtime.getRuntime().addShutdownHook(new Thread() {
027         @Override
028         public void run() {
029            if (! Boolean.getBoolean("SystemUtils.quiet"))
030            SHUTDOWN_MESSAGES.forEach(x -> System.out.println(x.get()));
031         }
032      });
033   }
034
035   /**
036    * Adds a console message to display when the JVM shuts down.
037    *
038    * @param message The message to display.
039    */
040   public static void shutdownMessage(Supplier<String> message) {
041      SHUTDOWN_MESSAGES.add(message);
042   }
043
044}