ViewVC logotype

Annotation of /jsr166/src/main/intro.html

Parent Directory Parent Directory | Revision Log Revision Log

Revision 1.21 - (hide annotations)
Sun Nov 18 18:03:10 2012 UTC (8 years, 7 months ago) by jsr166
Branch: MAIN
Changes since 1.20: +1 -1 lines
File MIME type: text/html
normalize whitespace after <p>

2     <html>
3     <head>
4 dl 1.12 <title>JSR 166 Introduction.</title>
5 tim 1.1 </head>
7     <body bgcolor="#ffffee" vlink="#0000aa" link="#cc0000">
8 dl 1.12 <h1>JSR 166 Introduction.</h1>
9 tim 1.1
10     by <a href="http://gee.cs.oswego.edu/dl">Doug Lea</a>
11     <p>
13 dl 1.19 This is maintenance repository of JSR166 specifications. For further
14     information, go to: <A
15 dl 1.9 HREF="http://altair.cs.oswego.edu/mailman/listinfo/concurrency-interest">
16 dl 1.14 http://altair.cs.oswego.edu/mailman/listinfo/concurrency-interest</A>.
17 dl 1.7
18 dl 1.19 <p><em>Note: The javadocs here do <em>not</em> include pre-existing
19     java classes (for example <tt>java.lang.Thread</tt>) that were changed
20 dl 1.20 as part of the JSR166 spec. On the other hand, the javadocs here do
21 dl 1.19 include some existing java.util Collection interfaces and classes that
22     are not part of the spec, but are included because some new methods
23     implement or inherit from their specifications.
24     </em>
25 dl 1.9
26 jsr166 1.21 <p>JSR-166 introduces package <tt>java.util.concurrent</tt>
27 dl 1.9 containing utility classes commonly useful in concurrent
28     programming. Like package <tt>java.util</tt>, it includes a few small
29 dl 1.16 standardized extensible frameworks, as well as other classes that
30 dl 1.9 provide useful functionality and are otherwise tedious or difficult to
31     implement.
33     <p>JSR-166 focusses on breadth, providing critical functionality
34     useful across a wide range of concurrent programming styles and
35     applications, ranging from low-level atomic operations, to
36     customizable locks and synchronization aids, to various concurrent
37     data structures, to high-level execution agents including thread
38     pools. This diversity reflects the range of contexts in which
39     developers of concurrent programs have been found to require or desire
40     support not previously available in J2SE, which also keeping the
41 dl 1.16 resulting package small; providing only functionality that has been
42     found to be worthwhile to standardize.
43 dl 1.9
44     <p>Descriptions and brief motivations for the main components may be
45     found in the associated package documentation. JSR-166 also includes
46     a few changes and additions in packages outside of
47     java.util.concurrent. Here are brief descriptions.
48 tim 1.1
49     <h2>Queues</h2>
51 dl 1.3 A basic (nonblocking) {@link java.util.Queue} interface extending
52 dl 1.9 {@link java.util.Collection} is introduced into
53     <tt>java.util</tt>. Existing class {@link java.util.LinkedList} is
54     adapted to support Queue, and a new non-thread-safe {@link
55     java.util.PriorityQueue} is added.
57     <h2>Threads</h2>
59 dl 1.13 Three minor changes are introduced to the {@link java.lang.Thread}
60     class:
61     <ul>
62     <li> It now allows per-thread installation of handlers for uncaught
63     exceptions. Ths optionally disassociates handlers from ThreadGroups,
64     which has proven to be too inflexible. (Note that the combination of
65     features in JSR-166 make ThreadGroups even less likely to be used in
66     most programs. Perhaps they will eventually be deprecated.)
68     <li> Access checks are no longer required when a Thread interrupts
69     <em>itself</em>. The <tt>interrupt</tt> method is the only way to
70     re-assert a thread's interruption status (and in the case of
71     self-interruption has no other effect than this). The check here
72     previously caused unjustifiable and uncontrollable failures when
73     restricted code invoked library code that must reassert interruption
74     to correctly propagate status when encountering some
75     <tt>InterruptedExceptions</tt>.
76     <li> The <tt>destroy</tt> method, which has never been implemented,
77     has finally been deprecated. This is just a spec change, reflecting
78 dl 1.15 the fact that that the reason it has never been implemented is that
79 dl 1.13 it was undesirable and unworkable.
80     </ul>
81 dl 1.9
82     <h2>Timing</h2>
84     Method <tt>nanoTime</tt> is added to {@link java.lang.System}. It
85     provides a high-precision timing facility that is distinct from and
86     uncoordinated with <tt>System.currentTimeMillis</tt>.
87 dl 1.8
88     <h2>Removing ThreadLocals</h2>
90 dl 1.9 The {@link java.lang.ThreadLocal} class now supports a means to remove
91     a ThreadLocal, which is needed in some thread-pool and worker-thread
92 dl 1.2 designs.
93 dl 1.9
95 tim 1.1
96     <hr>
97     </body>
98     </html>

ViewVC Help
Powered by ViewVC 1.1.27