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streamsupport-cfuture is a backport of the Java 8 CompletableFuture API with the current
Java 9 (JEP 266) enhancements for Java 6 to 8 and Android developers
/*
* Copyright (c) 2015, 2017, 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. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* 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.
*/
/**
* Covers a backport of the upgraded (JEP 266) Java 9 CompletableFuture API
* for Java 6 to 8 and Android developers.
*
* See JEP 266: More Concurrency Updates.
*
* Memory Consistency Properties
*
*
* Chapter 17 of The Java™ Language Specification defines
* the happens-before relation on memory operations such as reads and
* writes of shared variables. The results of a write by one thread are
* guaranteed to be visible to a read by another thread only if the write
* operation happens-before the read operation. The {@code synchronized}
* and {@code volatile} constructs, as well as the {@code Thread.start()} and
* {@code Thread.join()} methods, can form happens-before relationships.
* In particular:
*
*
* - Each action in a thread happens-before every action in that thread
* that comes later in the program's order.
*
*
- An unlock ({@code synchronized} block or method exit) of a monitor
* happens-before every subsequent lock ({@code synchronized} block or
* method entry) of that same monitor. And because the happens-before
* relation is transitive, all actions of a thread prior to unlocking
* happen-before all actions subsequent to any thread locking that
* monitor.
*
*
- A write to a {@code volatile} field happens-before every
* subsequent read of that same field. Writes and reads of {@code volatile}
* fields have similar memory consistency effects as entering and exiting
* monitors, but do not entail mutual exclusion locking.
*
*
- A call to {@code start} on a thread happens-before any action in
* the started thread.
*
*
- All actions in a thread happen-before any other thread
* successfully returns from a {@code join} on that thread.
*
*
*
* @since 9
*/
package java8.util.concurrent;