Mercurial > hg > graal-compiler
diff graal/com.oracle.jvmci.options/src/com/oracle/jvmci/options/StableOptionValue.java @ 21554:b1530a6cce8c
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 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/graal/com.oracle.jvmci.options/src/com/oracle/jvmci/options/StableOptionValue.java Tue May 26 23:21:15 2015 +0200 @@ -0,0 +1,75 @@ +/* + * Copyright (c) 2013, 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 com.oracle.jvmci.options; + +/** + * An option that always returns the same {@linkplain #getValue() value}. + */ +public class StableOptionValue<T> extends OptionValue<T> { + + /** + * Creates a stable option value. + */ + public StableOptionValue(T value) { + super(value); + } + + /** + * Used to assert the invariant for stability. Without using locks, this check is not safe + * against races and so it's only an assertion. + */ + private boolean getValueCalled; + + /** + * Creates an uninitialized stable option value for a subclass that initializes itself + * {@link #initialValue() lazily}. + */ + public StableOptionValue() { + } + + /** + * Gets the value of this option. + */ + @Override + public final T getValue() { + T result = super.getValue(); + assert initGetValueCalled(); + return result; + } + + private boolean initGetValueCalled() { + getValueCalled = true; + return true; + } + + /** + * {@inheritDoc} + * <p> + * This must only be called if {@link #getValue()} has never been called. + */ + @Override + public final void setValue(Object v) { + assert !getValueCalled; + super.setValue(v); + } +}