59 lines
1.3 KiB
Plaintext
59 lines
1.3 KiB
Plaintext
== Why is this an issue?
|
|
|
|
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.
|
|
|
|
|
|
=== Noncompliant code example
|
|
|
|
[source,java]
|
|
----
|
|
private volatile int count = 0;
|
|
private volatile boolean boo = false;
|
|
|
|
public void incrementCount() {
|
|
count++; // Noncompliant
|
|
}
|
|
|
|
public void toggleBoo(){
|
|
boo = !boo; // Noncompliant
|
|
}
|
|
----
|
|
|
|
|
|
=== Compliant solution
|
|
|
|
[source,java]
|
|
----
|
|
private AtomicInteger count = 0;
|
|
private boolean boo = false;
|
|
|
|
public void incrementCount() {
|
|
count.incrementAndGet();
|
|
}
|
|
|
|
public synchronized void toggleBoo() {
|
|
boo = !boo;
|
|
}
|
|
----
|
|
|
|
|
|
== Resources
|
|
|
|
* https://wiki.sei.cmu.edu/confluence/x/SjdGBQ[CERT, VNA02-J.] - Ensure that compound operations on shared variables are atomic
|
|
|
|
|
|
ifdef::env-github,rspecator-view[]
|
|
|
|
'''
|
|
== Implementation Specification
|
|
(visible only on this page)
|
|
|
|
include::message.adoc[]
|
|
|
|
'''
|
|
== Comments And Links
|
|
(visible only on this page)
|
|
|
|
include::comments-and-links.adoc[]
|
|
endif::env-github,rspecator-view[]
|