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comparison graal/com.oracle.jvmci.options/src/com/oracle/jvmci/options/StableOptionValue.java @ 21554:b1530a6cce8c

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renamed com.oracle.graal.[debug|options|hotspotvmconfig]* modules to com.oracle.jvmci.[debug|options|hotspotvmconfig]* modules (JBS:GRAAL-53)
author Doug Simon <doug.simon@oracle.com>
date Tue, 26 May 2015 23:21:15 +0200
parents graal/com.oracle.graal.options/src/com/oracle/graal/options/StableOptionValue.java@af909f4b80a9
children 47bebae7454f
comparison
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21553:0910a9497b02 21554:b1530a6cce8c
1 /*
2 * Copyright (c) 2013, 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 com.oracle.jvmci.options;
24
25 /**
26 * An option that always returns the same {@linkplain #getValue() value}.
27 */
28 public class StableOptionValue<T> extends OptionValue<T> {
29
30 /**
31 * Creates a stable option value.
32 */
33 public StableOptionValue(T value) {
34 super(value);
35 }
36
37 /**
38 * Used to assert the invariant for stability. Without using locks, this check is not safe
39 * against races and so it's only an assertion.
40 */
41 private boolean getValueCalled;
42
43 /**
44 * Creates an uninitialized stable option value for a subclass that initializes itself
45 * {@link #initialValue() lazily}.
46 */
47 public StableOptionValue() {
48 }
49
50 /**
51 * Gets the value of this option.
52 */
53 @Override
54 public final T getValue() {
55 T result = super.getValue();
56 assert initGetValueCalled();
57 return result;
58 }
59
60 private boolean initGetValueCalled() {
61 getValueCalled = true;
62 return true;
63 }
64
65 /**
66 * {@inheritDoc}
67 * <p>
68 * This must only be called if {@link #getValue()} has never been called.
69 */
70 @Override
71 public final void setValue(Object v) {
72 assert !getValueCalled;
73 super.setValue(v);
74 }
75 }