Java Reference
In-Depth Information
}
}
Noncompliant Code Example
In this noncompliant code example, an assignment expression appears as an operand of
the
&&
operator:
public void f(boolean a, boolean b, boolean flag) {
while ( (a = b) && flag ) {
/* ... */
}
}
Because
&&
is not a comparison operator, assignment is an illegal operand. Again, this
isfrequentlyacaseoftheprogrammermistakenlyusingtheassignmentoperator
=
instead
of the equals operator
==
.
Compliant Solution
When the assignment of
b
to
a
is unintentional, this conditional block is now executed
only when
a
is equal to
b
and flag is
true
:
public void f(boolean a, boolean b, boolean flag) {
while ( (a == b) && flag ) {
/* ... */
}
}
Applicability
The use of the assignment operator in controlling conditional expressions frequently in-
dicates programmer error and can result in unexpected behavior.
As an exception to this guideline, it is permitted to use the assignment operator in con-
ditional expressions when the assignment is not the controlling expression (that is, the as-
signment is a subexpression), as shown in the following compliant solution.
