001/*
002 * #%L
003 * Netarchivesuite - common - test
004 * %%
005 * Copyright (C) 2005 - 2014 The Royal Danish Library, the Danish State and University Library,
006 *             the National Library of France and the Austrian National Library.
007 * %%
008 * This program is free software: you can redistribute it and/or modify
009 * it under the terms of the GNU Lesser General Public License as
010 * published by the Free Software Foundation, either version 2.1 of the
011 * License, or (at your option) any later version.
012 * 
013 * This program is distributed in the hope that it will be useful,
014 * but WITHOUT ANY WARRANTY; without even the implied warranty of
015 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
016 * GNU General Lesser Public License for more details.
017 * 
018 * You should have received a copy of the GNU General Lesser Public
019 * License along with this program.  If not, see
020 * <http://www.gnu.org/licenses/lgpl-2.1.html>.
021 * #L%
022 */
023
024package dk.netarkivet.testutils;
025
026import java.lang.management.ManagementFactory;
027import java.lang.management.ThreadMXBean;
028
029public abstract class ThreadUtils {
030    private static ThreadGroup rootThreadGroup = null;
031
032    public static Thread[] getAllThreads() {
033        final ThreadGroup root = getRootThreadGroup();
034        final ThreadMXBean thbean = ManagementFactory.getThreadMXBean();
035        int nAlloc = thbean.getThreadCount();
036        int n = 0;
037        Thread[] threads;
038        do {
039            nAlloc *= 2;
040            threads = new Thread[nAlloc];
041            n = root.enumerate(threads, true);
042        } while (n == nAlloc);
043        return java.util.Arrays.copyOf(threads, n);
044    }
045
046    public static ThreadGroup getRootThreadGroup() {
047        if (rootThreadGroup != null) {
048            return rootThreadGroup;
049        }
050        ThreadGroup tg = Thread.currentThread().getThreadGroup();
051        ThreadGroup ptg;
052        while ((ptg = tg.getParent()) != null) {
053            tg = ptg;
054        }
055        return tg;
056    }
057}