Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
ConcurrentQueue |
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ConcurrentQueue$Handle |
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1 | /* | |
2 | * | |
3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. | |
4 | * | |
5 | * Copyright 2007-2008 Sun Microsystems, Inc. All rights reserved. | |
6 | * | |
7 | * The contents of this file are subject to the terms of either the GNU | |
8 | * General Public License Version 2 only ("GPL") or the Common Development | |
9 | * and Distribution License("CDDL") (collectively, the "License"). You | |
10 | * may not use this file except in compliance with the License. You can obtain | |
11 | * a copy of the License at https://glassfish.dev.java.net/public/CDDL+GPL.html | |
12 | * or glassfish/bootstrap/legal/LICENSE.txt. See the License for the specific | |
13 | * language governing permissions and limitations under the License. | |
14 | * | |
15 | * When distributing the software, include this License Header Notice in each | |
16 | * file and include the License file at glassfish/bootstrap/legal/LICENSE.txt. | |
17 | * Sun designates this particular file as subject to the "Classpath" exception | |
18 | * as provided by Sun in the GPL Version 2 section of the License file that | |
19 | * accompanied this code. If applicable, add the following below the License | |
20 | * Header, with the fields enclosed by brackets [] replaced by your own | |
21 | * identifying information: "Portions Copyrighted [year] | |
22 | * [name of copyright owner]" | |
23 | * | |
24 | * Contributor(s): | |
25 | * | |
26 | * If you wish your version of this file to be governed by only the CDDL or | |
27 | * only the GPL Version 2, indicate your decision by adding "[Contributor] | |
28 | * elects to include this software in this distribution under the [CDDL or GPL | |
29 | * Version 2] license." If you don't indicate a single choice of license, a | |
30 | * recipient has the option to distribute your version of this file under | |
31 | * either the CDDL, the GPL Version 2 or to extend the choice of license to | |
32 | * its licensees as provided above. However, if you add GPL Version 2 code | |
33 | * and therefore, elected the GPL Version 2 license, then the option applies | |
34 | * only if the new code is made subject to such option by the copyright | |
35 | * holder. | |
36 | * | |
37 | */ | |
38 | ||
39 | package com.sun.grizzly.connectioncache.spi.concurrent; | |
40 | ||
41 | /** A class that provides a very simply unbounded queue. | |
42 | * The main requirement here is that the class support constant time (very fast) | |
43 | * deletion of arbitrary elements. An instance of this class must be thread safe, | |
44 | * either by locking or by using a wait-free algorithm (preferred). | |
45 | * The interface is made as simple is possible to make it easier to produce | |
46 | * a wait-free implementation. | |
47 | * @param V object type to be stored in this <code>ConcurrentQueue</code> | |
48 | */ | |
49 | public interface ConcurrentQueue<V> { | |
50 | /** A Handle provides the capability to delete an element of a ConcurrentQueue | |
51 | * very quickly. Typically, the handle is stored in the element, so that an | |
52 | * element located from another data structure can be quickly deleted from | |
53 | * a ConcurrentQueue. | |
54 | * @param V type of {@link Handle} | |
55 | */ | |
56 | public interface Handle<V> { | |
57 | /** Return the value that corresponds to this handle. | |
58 | * @return value that corresponds to this handle | |
59 | */ | |
60 | V value() ; | |
61 | ||
62 | /** Delete the element corresponding to this handle | |
63 | * from the queue. Takes constant time. Returns | |
64 | * true if the removal succeeded, or false if it failed. | |
65 | * which can occur if another thread has already called | |
66 | * poll or remove on this element. | |
67 | * @return true if the removal succeeded, or false if it failed | |
68 | */ | |
69 | boolean remove() ; | |
70 | } | |
71 | ||
72 | /** Return the number of elements in the queue. | |
73 | * @return number of elements in the queue | |
74 | */ | |
75 | int size() ; | |
76 | ||
77 | /** Add a new element to the tail of the queue. | |
78 | * Returns a handle for the element in the queue. | |
79 | * @param arg element to add to the queue | |
80 | * @return a {@link Handle} for the element added to the queue | |
81 | */ | |
82 | Handle<V> offer( V arg ) ; | |
83 | ||
84 | /** Return an element from the head of the queue. | |
85 | * The element is removed from the queue. | |
86 | * @return element removed from the queue | |
87 | */ | |
88 | V poll() ; | |
89 | } |