49 lines
1.5 KiB
Plaintext
49 lines
1.5 KiB
Plaintext
== Why is this an issue?
|
|
|
|
When using ``++Math.min()++`` and ``++Math.max()++`` together for bounds checking, it's important to feed the right operands to each method. ``++Math.min()++`` should be used with the *upper* end of the range being checked, and ``++Math.max()++`` should be used with the *lower* end of the range. Get it backwards, and the result will always be the same end of the range.
|
|
|
|
|
|
=== Noncompliant code example
|
|
|
|
[source,text]
|
|
----
|
|
private static final int UPPER = 20;
|
|
private static final int LOWER = 0;
|
|
|
|
public int doRangeCheck(int num) { // Let's say num = 12
|
|
int result = Math.min(LOWER, num); // result = 0
|
|
return Math.max(UPPER, result); // Noncompliant; result is now 20: even though 12 was in the range
|
|
}
|
|
----
|
|
|
|
|
|
=== Compliant solution
|
|
|
|
Swapping method ``++min()++`` and ``++max()++`` invocations without changing parameters.
|
|
|
|
[source,text]
|
|
----
|
|
private static final int UPPER = 20;
|
|
private static final int LOWER = 0;
|
|
|
|
public int doRangeCheck(int num) { // Let's say num = 12
|
|
int result = Math.max(LOWER, num); // result = 12
|
|
return Math.min(UPPER, result); // Compliant; result is still 12
|
|
}
|
|
----
|
|
|
|
or swapping bounds ``++UPPER++`` and ``++LOWER++`` used as parameters without changing the invoked methods.
|
|
|
|
|
|
[source,text]
|
|
----
|
|
private static final int UPPER = 20;
|
|
private static final int LOWER = 0;
|
|
|
|
public int doRangeCheck(int num) { // Let's say num = 12
|
|
int result = Math.min(UPPER, num); // result = 12
|
|
return Math.max(LOWER, result); // Compliant; result is still 12
|
|
}
|
|
----
|
|
|