1 /* 2 * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 package jdk.test.lib.util; 25 26 import java.lang.ref.Cleaner; 27 import java.util.concurrent.CountDownLatch; 28 import java.util.concurrent.TimeUnit; 29 import java.util.function.BooleanSupplier; 30 31 /** 32 * Utility class to invoke System.gc() 33 */ 34 public class ForceGC { 35 private final CountDownLatch cleanerInvoked = new CountDownLatch(1); 36 private final Cleaner cleaner = Cleaner.create(); 37 public ForceGC() { 38 cleaner.register(new Object(), () -> cleanerInvoked.countDown()); 39 } 40 41 private void doit() { 42 try { 43 for (int i = 0; i < 10; i++) { 44 System.gc(); 45 System.out.println("gc " + i); 46 if (cleanerInvoked.await(1L, TimeUnit.SECONDS)) { 47 return; 48 } 49 } 50 } catch (InterruptedException unexpected) { 51 throw new AssertionError("unexpected InterruptedException"); 52 } 53 } 54 55 /** 56 * Causes the current thread to wait until the {@code BooleanSupplier} returns true, 57 * unless the thread is interrupted or a predefined waiting time elapses. 58 * 59 * @param s boolean supplier 60 * @return true if the {@code BooleanSupplier} returns true and false if 61 * the predefined waiting time elapsed before the count reaches zero. 62 * @throws InterruptedException if the current thread is interrupted while waiting 63 */ 64 public boolean await(BooleanSupplier s) { 65 for (int i = 0; i < 10; i++) { 66 if (s.getAsBoolean()) return true; 67 doit(); 68 } 69 return false; 70 } 71 }