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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

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java/pkg/java/util/concurrent/CompletionService.java+126−0
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1+/*
2+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3+ *
4+ * This code is free software; you can redistribute it and/or modify it
5+ * under the terms of the GNU General Public License version 2 only, as
6+ * published by the Free Software Foundation. Oracle designates this
7+ * particular file as subject to the "Classpath" exception as provided
8+ * by Oracle in the LICENSE file that accompanied this code.
9+ *
10+ * This code is distributed in the hope that it will be useful, but WITHOUT
11+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13+ * version 2 for more details (a copy is included in the LICENSE file that
14+ * accompanied this code).
15+ *
16+ * You should have received a copy of the GNU General Public License version
17+ * 2 along with this work; if not, write to the Free Software Foundation,
18+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19+ *
20+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21+ * or visit www.oracle.com if you need additional information or have any
22+ * questions.
23+ */
24+
25+/*
26+ * This file is available under and governed by the GNU General Public
27+ * License version 2 only, as published by the Free Software Foundation.
28+ * However, the following notice accompanied the original version of this
29+ * file:
30+ *
31+ * Written by Doug Lea with assistance from members of JCP JSR-166
32+ * Expert Group and released to the public domain, as explained at
33+ * http://creativecommons.org/publicdomain/zero/1.0/
34+ */
35+
36+package java.util.concurrent;
37+
38+/**
39+ * A service that decouples the production of new asynchronous tasks
40+ * from the consumption of the results of completed tasks. Producers
41+ * <tt>submit</tt> tasks for execution. Consumers <tt>take</tt>
42+ * completed tasks and process their results in the order they
43+ * complete. A <tt>CompletionService</tt> can for example be used to
44+ * manage asynchronous IO, in which tasks that perform reads are
45+ * submitted in one part of a program or system, and then acted upon
46+ * in a different part of the program when the reads complete,
47+ * possibly in a different order than they were requested.
48+ *
49+ * <p>Typically, a <tt>CompletionService</tt> relies on a separate
50+ * {@link Executor} to actually execute the tasks, in which case the
51+ * <tt>CompletionService</tt> only manages an internal completion
52+ * queue. The {@link ExecutorCompletionService} class provides an
53+ * implementation of this approach.
54+ *
55+ * <p>Memory consistency effects: Actions in a thread prior to
56+ * submitting a task to a {@code CompletionService}
57+ * <a href="package-summary.html#MemoryVisibility"><i>happen-before</i></a>
58+ * actions taken by that task, which in turn <i>happen-before</i>
59+ * actions following a successful return from the corresponding {@code take()}.
60+ *
61+ */
62+public interface CompletionService<V> {
63+ /**
64+ * Submits a value-returning task for execution and returns a Future
65+ * representing the pending results of the task. Upon completion,
66+ * this task may be taken or polled.
67+ *
68+ * @param task the task to submit
69+ * @return a Future representing pending completion of the task
70+ * @throws RejectedExecutionException if the task cannot be
71+ * scheduled for execution
72+ * @throws NullPointerException if the task is null
73+ */
74+ Future<V> submit(Callable<V> task);
75+
76+ /**
77+ * Submits a Runnable task for execution and returns a Future
78+ * representing that task. Upon completion, this task may be
79+ * taken or polled.
80+ *
81+ * @param task the task to submit
82+ * @param result the result to return upon successful completion
83+ * @return a Future representing pending completion of the task,
84+ * and whose <tt>get()</tt> method will return the given
85+ * result value upon completion
86+ * @throws RejectedExecutionException if the task cannot be
87+ * scheduled for execution
88+ * @throws NullPointerException if the task is null
89+ */
90+ Future<V> submit(Runnable task, V result);
91+
92+ /**
93+ * Retrieves and removes the Future representing the next
94+ * completed task, waiting if none are yet present.
95+ *
96+ * @return the Future representing the next completed task
97+ * @throws InterruptedException if interrupted while waiting
98+ */
99+ Future<V> take() throws InterruptedException;
100+
101+
102+ /**
103+ * Retrieves and removes the Future representing the next
104+ * completed task or <tt>null</tt> if none are present.
105+ *
106+ * @return the Future representing the next completed task, or
107+ * <tt>null</tt> if none are present
108+ */
109+ Future<V> poll();
110+
111+ /**
112+ * Retrieves and removes the Future representing the next
113+ * completed task, waiting if necessary up to the specified wait
114+ * time if none are yet present.
115+ *
116+ * @param timeout how long to wait before giving up, in units of
117+ * <tt>unit</tt>
118+ * @param unit a <tt>TimeUnit</tt> determining how to interpret the
119+ * <tt>timeout</tt> parameter
120+ * @return the Future representing the next completed task or
121+ * <tt>null</tt> if the specified waiting time elapses
122+ * before one is present
123+ * @throws InterruptedException if interrupted while waiting
124+ */
125+ Future<V> poll(long timeout, TimeUnit unit) throws InterruptedException;
126+}