Java Reference
In-Depth Information
[Long 2012]
NUM01-J.Donotperformbitwiseandarithmeticoperationsonthesamedata
40. Properly encode relationships in constant definitions
Thedefinitionsofconstantexpressionsshouldberelated
exactly
whenthevaluestheyex-
press are also related.
Noncompliant Code Example
In this noncompliant code example,
OUT_STR_LEN
must always be exactly two greater
than
IN_STR_LEN
. These definitions fail to reflect this requirement:
public static final int IN_STR_LEN = 18;
public static final int OUT_STR_LEN = 20;
Compliant Solution
In this compliant solution, the relationship between the two values is represented in the
definitions:
public static final int IN_STR_LEN = 18;
public static final int OUT_STR_LEN = IN_STR_LEN + 2;
Noncompliant Code Example
In this noncompliant code example, there appears to be an underlying relationship
between the two constants where none exists:
public static final int VOTING_AGE = 18;
public static final int ALCOHOL_AGE = VOTING_AGE + 3;
A programmer performing routine maintenance may modify the definition for
VOTING_AGE
, but fail to recognize the resulting change in the definition for
ALCOHOL_AGE
.
