1 /* 2 * Copyright (c) 2014, 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 package jdk.vm.ci.options; 24 25 import java.io.Serializable; 26 import java.util.function.Supplier; 27 28 import jdk.vm.ci.options.OptionValue.OverrideScope; 29 30 /** 31 * A cached value that needs to be recomputed when an option changes. 32 */ 33 public class DerivedOptionValue<T> { 34 35 public interface OptionSupplier<T> extends Supplier<T>, Serializable { 36 } 37 38 private final T initialValue; 39 private final OptionSupplier<T> supplier; 40 41 public DerivedOptionValue(OptionSupplier<T> supplier) { 42 this.supplier = supplier; 43 assert OptionValue.getOverrideScope() == null : "derived option value should be initialized outside any override scope"; 44 this.initialValue = createValue(); 45 } 46 47 public T getValue() { 48 OverrideScope overrideScope = OptionValue.getOverrideScope(); 49 if (overrideScope != null) { 50 return overrideScope.getDerived(this); 51 } else { 52 return initialValue; 53 } 54 } 55 56 T createValue() { 57 return supplier.get(); 58 } 59 }