10 |
|
by <a href="http://gee.cs.oswego.edu/dl">Doug Lea</a> |
11 |
|
<p> |
12 |
|
|
13 |
< |
This is the updated JSR166 specification. For further information, go |
14 |
< |
to: <A |
13 |
> |
This is maintenance repository of JSR166 specifications. For further |
14 |
> |
information, go to: <A |
15 |
|
HREF="http://altair.cs.oswego.edu/mailman/listinfo/concurrency-interest"> |
16 |
|
http://altair.cs.oswego.edu/mailman/listinfo/concurrency-interest</A>. |
17 |
|
|
18 |
< |
<p><em>Note: The javadocs here includes some existing java.util |
19 |
< |
Collection interfaces and classes that are not part of the JSR-166 |
20 |
< |
spec, but are included because JSR-166 methods implement or inherit |
21 |
< |
from their specifications.</em> |
18 |
> |
<p><em>Note: The javadocs here do <em>not</em> include pre-existing |
19 |
> |
java classes (for example <code>java.lang.Thread</code>) that were changed |
20 |
> |
as part of the JSR166 spec. On the other hand, the javadocs here do |
21 |
> |
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 |
|
|
26 |
< |
<p> JSR-166 introduces package <tt>java.util.concurrent</tt> |
26 |
> |
<p>JSR-166 introduces package <code>java.util.concurrent</code> |
27 |
|
containing utility classes commonly useful in concurrent |
28 |
< |
programming. Like package <tt>java.util</tt>, it includes a few small |
28 |
> |
programming. Like package <code>java.util</code>, it includes a few small |
29 |
|
standardized extensible frameworks, as well as other classes that |
30 |
|
provide useful functionality and are otherwise tedious or difficult to |
31 |
|
implement. |
32 |
|
|
33 |
< |
<p>JSR-166 focusses on breadth, providing critical functionality |
33 |
> |
<p>JSR-166 focuses 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 |
50 |
|
|
51 |
|
A basic (nonblocking) {@link java.util.Queue} interface extending |
52 |
|
{@link java.util.Collection} is introduced into |
53 |
< |
<tt>java.util</tt>. Existing class {@link java.util.LinkedList} is |
53 |
> |
<code>java.util</code>. 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. |
56 |
|
|
60 |
|
class: |
61 |
|
<ul> |
62 |
|
<li> It now allows per-thread installation of handlers for uncaught |
63 |
< |
exceptions. Ths optionally disassociates handlers from ThreadGroups, |
63 |
> |
exceptions. This 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.) |
67 |
|
|
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 |
69 |
> |
<em>itself</em>. The <code>interrupt</code> 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, |
75 |
> |
<code>InterruptedExceptions</code>. |
76 |
> |
<li> The <code>destroy</code> method, which has never been implemented, |
77 |
|
has finally been deprecated. This is just a spec change, reflecting |
78 |
< |
the fact that that the reason it has never been implemented is that |
78 |
> |
the fact that the reason it has never been implemented is that |
79 |
|
it was undesirable and unworkable. |
80 |
|
</ul> |
81 |
|
|
82 |
|
<h2>Timing</h2> |
83 |
|
|
84 |
< |
Method <tt>nanoTime</tt> is added to {@link java.lang.System}. It |
84 |
> |
Method <code>nanoTime</code> 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>. |
86 |
> |
uncoordinated with <code>System.currentTimeMillis</code>. |
87 |
|
|
88 |
|
<h2>Removing ThreadLocals</h2> |
89 |
|
|