001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     * 
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     * 
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the License for the specific language governing permissions and
015     * limitations under the License.
016     */
017    
018    package org.apache.commons.launcher;
019    
020    /**
021     * A class that subclasses the {@link ThreadGroup} class. This class is used
022     * by {@link ChildMain#main(String[])} to run the target application. By using
023     * this class, any {@link Error} other than {@link ThreadDeath} thrown by
024     * threads created by the target application will be caught the process
025     * terminated. By default, the JVM will only print a stack trace of the
026     * {@link Error} and destroy the thread. However, when an uncaught
027     * {@link Error} occurs, it normally means that the JVM has encountered a
028     * severe problem. Hence, an orderly shutdown is a reasonable approach.
029     * <p>
030     * Note: not all threads created by the target application are guaranteed to
031     * use this class. Target application's may bypass this class by creating a
032     * thread using the {@link Thread#Thread(ThreadGroup, String)} or other similar
033     * constructors.
034     *
035     * @author Patrick Luby
036     */
037    public class ExitOnErrorThreadGroup extends ThreadGroup {
038    
039        //------------------------------------------------------------ Constructors
040    
041        /**
042         * Constructs a new thread group. The parent of this new group is the
043         * thread group of the currently running thread.
044         *
045         * @param name the name of the new thread group
046         */
047        public ExitOnErrorThreadGroup(String name) {
048    
049            super(name);
050    
051        }
052    
053        //----------------------------------------------------------------- Methods
054    
055        /**
056         * Trap any uncaught {@link Error} other than {@link ThreadDeath} and exit.
057         *
058         * @param t the thread that is about to exit
059         * @param e the uncaught exception
060         */
061        public void uncaughtException(Thread t, Throwable e) {
062    
063            if (e instanceof ThreadDeath)
064                return;
065    
066            Launcher.error(e);
067            System.exit(1);
068    
069        }
070    
071    }