DerivedOptionValue.java revision 12651:6ef01bd40ce2 
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 */
23package org.graalvm.compiler.options;
24
25import java.io.Serializable;
26import java.util.function.Supplier;
27
28import org.graalvm.compiler.options.OptionValue.OverrideScope;
29
30/**
31 * A cached value that needs to be recomputed when an option changes.
32 */
33public class DerivedOptionValue<T> {
34
35    public interface OptionSupplier<T> extends Supplier<T>, Serializable {
36    }
37
38    private T initialValue;
39    private final OptionSupplier<T> supplier;
40
41    public DerivedOptionValue(OptionSupplier<T> supplier) {
42        this.supplier = supplier;
43    }
44
45    public T getValue() {
46        OverrideScope overrideScope = OptionValue.getOverrideScope();
47        if (overrideScope != null) {
48            return overrideScope.getDerived(this);
49        } else {
50            if (initialValue == null) {
51                initialValue = createValue();
52            }
53            return initialValue;
54        }
55    }
56
57    T createValue() {
58        return supplier.get();
59    }
60}
61