ConstantName

Since Checkstyle 3.0

Description

Checks that constant names conform to a specified pattern. A constant is a static and final field or an interface/annotation field, except serialVersionUID and serialPersistentFields.

Properties

name description type default value since
applyToPackage Control if check should apply to package-private members. boolean true 5.0
applyToPrivate Control if check should apply to private members. boolean true 5.0
applyToProtected Control if check should apply to protected members. boolean true 5.0
applyToPublic Control if check should apply to public members. boolean true 5.0
format Sets the pattern to match valid identifiers. Pattern "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$" 3.0

Examples

To configure the check: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="ConstantName"/>
  </module>
</module>

Example:

class Example1 {
  public final static int FIRST_CONSTANT1 = 10;
  protected final static int SECOND_CONSTANT2 = 100;
  final static int third_Constant3 = 1000; // violation 'must match pattern'
  private final static int fourth_Const4 = 50; // violation 'must match pattern'
  public final static int log = 10; // violation 'must match pattern'
  protected final static int logger = 50; // violation 'must match pattern'
  final static int loggerMYSELF = 5; // violation 'must match pattern'
  final static int MYSELF = 100;
  protected final static int myselfConstant = 1; // violation 'must match pattern'
}

The following configuration apart from names allowed by default allows log or logger: 

<module name="Checker">
  <module name="TreeWalker">
    <module name="ConstantName">
      <property name="format"
                value="^log(ger)?$|^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$"/>
    </module>
  </module>
</module>

Code Example:

class Example2 {
  public final static int FIRST_CONSTANT1 = 10;
  protected final static int SECOND_CONSTANT2 = 100;
  final static int third_Constant3 = 1000; // violation 'must match pattern'
  private final static int fourth_Const4 = 50; // violation 'must match pattern'
  public final static int log = 10;
  protected final static int logger = 50;
  final static int loggerMYSELF = 5; // violation 'must match pattern'
  final static int MYSELF = 100;
  protected final static int myselfConstant = 1; // violation 'must match pattern'
}

The following configuration skip validation on public constant field and protected constant field. 

<module name="Checker">
  <module name="TreeWalker">
    <module name="ConstantName">
      <property name="applyToPublic" value="false"/>
      <property name="applyToProtected" value="false"/>
    </module>
  </module>
</module>

Code Example:

class Example3 {
  public final static int FIRST_CONSTANT1 = 10;
  protected final static int SECOND_CONSTANT2 = 100;
  final static int third_Constant3 = 1000; // violation 'must match pattern'
  private final static int fourth_Const4 = 50; // violation 'must match pattern'
  public final static int log = 10;
  protected final static int logger = 50;
  final static int loggerMYSELF = 5; // violation 'must match pattern'
  final static int MYSELF = 100;
  protected final static int myselfConstant = 1;
}

Example of Usage

Violation Messages

All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.

Package

com.puppycrawl.tools.checkstyle.checks.naming

Parent Module

TreeWalker