16f6c0aecf
Inline adoc files when they are included exactly once. Also fix language tags because this inlining gives us better information on what language the code is written in.
73 lines
2.0 KiB
Plaintext
73 lines
2.0 KiB
Plaintext
== Why is this an issue?
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Using compound operators as well as increments and decrements (and toggling, in the case of ``++boolean++``s) on primitive fields are not atomic operations. That is, they don't happen in a single step. For instance, when a ``++volatile++`` primitive field is incremented or decremented you run the risk of data loss if threads interleave in the steps of the update. Instead, use a guaranteed-atomic class such as ``++AtomicInteger++``, or synchronize the access.
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=== Noncompliant code example
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[source,java]
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----
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private volatile int count = 0;
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private volatile boolean boo = false;
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public void incrementCount() {
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count++; // Noncompliant
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}
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public void toggleBoo(){
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boo = !boo; // Noncompliant
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}
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----
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=== Compliant solution
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[source,java]
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----
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private AtomicInteger count = 0;
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private boolean boo = false;
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public void incrementCount() {
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count.incrementAndGet();
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}
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public synchronized void toggleBoo() {
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boo = !boo;
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}
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----
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== Resources
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* https://wiki.sei.cmu.edu/confluence/x/SjdGBQ[CERT, VNA02-J.] - Ensure that compound operations on shared variables are atomic
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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=== Message
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Use an "Atomic[Integer|Long]" for this field; its operations are atomic.
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'''
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== Comments And Links
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(visible only on this page)
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=== on 18 Jun 2015, 18:34:53 Nicolas Peru wrote:
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Title was a bit ambiguous I let you modify it if you think it is a bit redundant.
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=== on 18 Jun 2015, 18:36:55 Ann Campbell wrote:
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Thank you [~nicolas.peru]. That's what I get for writing the title before I fully understand what the description should say. :)
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=== on 19 Jun 2015, 15:50:31 Ann Campbell wrote:
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\[~nicolas.peru] I just realized that in response to your 'redundant' comment I simply undid the change you had made. But at root, is there a 'safe' way to increment a ``++volatile++`` var?
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=== on 13 Oct 2015, 08:06:59 Nicolas Peru wrote:
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Modified title.
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endif::env-github,rspecator-view[]
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