--- /dev/null 2017-01-22 10:16:57.869617664 -0800 +++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.options/src/org/graalvm/compiler/options/DerivedOptionValue.java 2017-02-15 17:08:03.277337828 -0800 @@ -0,0 +1,60 @@ +/* + * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * This code is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 only, as + * published by the Free Software Foundation. + * + * This code is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + * version 2 for more details (a copy is included in the LICENSE file that + * accompanied this code). + * + * You should have received a copy of the GNU General Public License version + * 2 along with this work; if not, write to the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. + * + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA + * or visit www.oracle.com if you need additional information or have any + * questions. + */ +package org.graalvm.compiler.options; + +import java.io.Serializable; +import java.util.function.Supplier; + +import org.graalvm.compiler.options.OptionValue.OverrideScope; + +/** + * A cached value that needs to be recomputed when an option changes. + */ +public class DerivedOptionValue { + + public interface OptionSupplier extends Supplier, Serializable { + } + + private T initialValue; + private final OptionSupplier supplier; + + public DerivedOptionValue(OptionSupplier supplier) { + this.supplier = supplier; + } + + public T getValue() { + OverrideScope overrideScope = OptionValue.getOverrideScope(); + if (overrideScope != null) { + return overrideScope.getDerived(this); + } else { + if (initialValue == null) { + initialValue = createValue(); + } + return initialValue; + } + } + + T createValue() { + return supplier.get(); + } +}