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The definitions of two constant expressions should be related when, and only when, the values they express are also related.

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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:

Code Block
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public static final int IN_STR_LEN = 18;
public static final int OUT_STR_LEN = 12;

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Compliant Solution

In this compliant solution, the relationship between the two values is represented in the definitions:

Code Block
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public static final int IN_STR_LEN = 18;
public static final int OUT_STR_LEN = IN_STR_LEN + 2;

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Noncompliant Code Example

In this noncompliant code example, there appears to be an underlying relationship between the two constants where none exists.

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A programmer performing routine maintenance may modify the definition for ADULT_AGE but fail to recognize the resulting change in the definition for ALCOHOL_AGE.

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Compliant Solution

In this compliant solution, the definitions reflect the independence of the two constants.

Code Block
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public static final int ADULT_AGE = 18;
public static final int ALCOHOL_AGE = 21;

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Risk Assessment

Failure to properly encode relationships in constant declarations can lead to unexpected values and can complicate maintenance.

Guideline

Severity

Likelihood

Remediation Cost

Priority

Level

DCL03-J

low

unlikely

high

P1

L3

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Automated Detection

Automated detection is not currently feasible.

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Related Guidelines

C Secure Coding Standard: DCL08-C. Properly encode relationships in constant definitions

C++ Secure Coding Standard: DCL08-CPP. Properly encode relationships in constant definitions

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Bibliography

Wiki Markup
\[[JLS 2005|AA. Bibliography#JLS 05]\] [§ 4.12.4, "{{final}} Variables"|http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.12.4]

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