1 /* 2 * Copyright (c) 2014, 2018, 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 vm.mlvm.indy.share; 25 26 import java.lang.invoke.MethodHandle; 27 import java.lang.invoke.MethodHandles; 28 import java.lang.invoke.CallSite; 29 import vm.mlvm.share.DekkerTest; 30 31 /** 32 * The class implements Actor for {@link vm.mlvm.share.DekkerTest}. 33 * <p> 34 * This Actor switches targets for CallSite objects supplied in constructor. 35 * Targets are method handles, generated with MethodHandle.constant(), which return true or false. 36 * CallSite.setTarget() is used for setting appropriate target. 37 * CallSite.dynamicInvoker().invokeExact() is used to detect which target is currently set. 38 * No synchronization is used between setter and getter (see {@link vm.mlvm.share.DekkerTest} for details). 39 * 40 * @see vm.mlvm.share.DekkerTest 41 */ 42 public class CallSiteDekkerActor implements DekkerTest.Actor { 43 44 public static final MethodHandle MH_FALSE = MethodHandles.constant(Boolean.class, false); 45 public static final MethodHandle MH_TRUE = MethodHandles.constant(Boolean.class, true); 46 47 private final CallSite a; 48 private final CallSite b; 49 50 public CallSiteDekkerActor(CallSite csa, CallSite csb) { 51 a = csa; 52 b = csb; 53 } 54 55 @Override 56 public void reset() { 57 a.setTarget(MH_FALSE); 58 b.setTarget(MH_FALSE); 59 } 60 61 @Override 62 public boolean actorA() throws Throwable { 63 a.setTarget(MH_TRUE); 64 return (Boolean) b.dynamicInvoker().invokeExact(); 65 } 66 67 @Override 68 public boolean actorB() throws Throwable { 69 b.setTarget(MH_TRUE); 70 return (Boolean) a.dynamicInvoker().invokeExact(); 71 } 72 }