Since Checkstyle 3.0
Checks that local final variable names conform to a specified pattern. A catch parameter and resources in try statements are considered to be a local, final variables.
name | description | type | default value | since |
---|---|---|---|---|
format | Specifies valid identifiers. | Pattern | "^[a-z][a-zA-Z0-9]*$" |
3.0 |
tokens | tokens to check | subset of tokens VARIABLE_DEF , PARAMETER_DEF , RESOURCE . | VARIABLE_DEF , PARAMETER_DEF , RESOURCE . | 3.0 |
To configure the check:
<module name="Checker"> <module name="TreeWalker"> <module name="LocalFinalVariableName"/> </module> </module>
An example of how to configure the check for names that are only upper case letters and digits is:
<module name="Checker"> <module name="TreeWalker"> <module name="LocalFinalVariableName"> <property name="format" value="^[A-Z][A-Z0-9]*$"/> </module> </module> </module>
Code Example:
class MyClass { void MyMethod() { try { final int VAR1 = 5; // OK final int var1 = 10; // violation, name 'var1' must match pattern "^[A-Z][A-Z0-9]*$" } catch (Exception ex) { final int VAR2 = 15; // OK final int var2 = 20; // violation, name 'var2' must match pattern "^[A-Z][A-Z0-9]*$" } } }
An example of how to configure the check for names of local final parameters and resources in try statements (without checks on variables):
<module name="Checker"> <module name="TreeWalker"> <module name="LocalFinalVariableName"> <property name="format" value="^[A-Z][A-Z0-9]*$"/> <property name="tokens" value="PARAMETER_DEF,RESOURCE"/> </module> </module> </module>
Code Example:
class MyClass { void MyMethod() { try(Scanner scanner = new Scanner()) { // violation, name 'scanner' must // match pattern '^[A-Z][A-Z0-9]*$' final int VAR1 = 5; // OK final int var1 = 10; // OK } catch (final Exception ex) { // violation, name 'ex' // must match pattern '^[A-Z][A-Z0-9]*$' final int VAR2 = 15; // OK final int var2 = 20; // OK } } }
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
com.puppycrawl.tools.checkstyle.checks.naming