Package com.puppycrawl.tools.checkstyle.checks.naming

Class ParameterNameCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable
    public class ParameterNameCheck
extends AbstractNameCheck

    Checks that method parameter names conform to a specified pattern. By using accessModifiers property it is possible to specify different formats for methods at different visibility levels.

    To validate catch parameters please use CatchParameterName.

    To validate lambda parameters please use LambdaParameterName.

    • Property format - Specifies valid identifiers. Type is java.util.regex.Pattern. Default value is "^[a-z][a-zA-Z0-9]*$".
    • Property ignoreOverridden - Allows to skip methods with Override annotation from validation. Type is boolean. Default value is false.
    • Property accessModifiers - Access modifiers of methods where parameters are checked. Type is com.puppycrawl.tools.checkstyle.checks.naming.AccessModifierOption[]. Default value is public, protected, package, private.

    To configure the check: 

     <module name="ParameterName"/>

    Code Example:

     class MyClass {
   void method1(int v1) {} // OK
   void method2(int V2) {} // violation, name 'V2' must match pattern '^[a-z][a-zA-Z0-9]*$'
 }

    An example of how to configure the check for names that begin with a lower case letter, followed by letters, digits, and underscores: 

     <module name="ParameterName">
   <property name="format" value="^[a-z][_a-zA-Z0-9]+$"/>
 </module>

    Code Example:

     class MyClass {
   void method1(int v1) {} // OK
   void method2(int v_2) {} // OK
   void method3(int V3) {} // violation, name 'V3' must match pattern '^[a-z][_a-zA-Z0-9]+$'
 }

    An example of how to configure the check to skip methods with Override annotation from validation: 

     <module name="ParameterName">
   <property name="ignoreOverridden" value="true"/>
 </module>

    Code Example:

     class MyClass {
   void method1(int v1) {} // OK
   void method2(int V2) {} // violation, name 'V2' must match pattern '^[a-z][a-zA-Z0-9]*$'
   @Override
   public boolean equals(Object V3) { // OK
       return true;
   }
 }

    An example of how to configure the check for names that begin with a lower case letter, followed by letters and digits is: 

     <module name="ParameterName">
   <property name="format" value="^[a-z][a-zA-Z0-9]+$"/>
 </module>

    Code Example:

     class MyClass {
   void method1(int v1) {} // OK
   void method2(int v_2) {} // violation, name 'v_2' must match pattern '^[a-z][a-zA-Z0-9]+$'
   void method3(int V3) {} // violation, name 'V3' must match pattern '^[a-z][a-zA-Z0-9]+$'
 }

    The following configuration checks that the parameters always start with two lowercase characters and, in addition, that public method parameters cannot be one character long: 

     <module name="ParameterName">
   <property name="format" value="^[a-z]([a-z0-9][a-zA-Z0-9]*)?$"/>
   <property name="accessModifiers"
     value="protected, package, private"/>
   <message key="name.invalidPattern"
     value="Parameter name ''{0}'' must match pattern ''{1}''"/>
 </module>
 <module name="ParameterName">
   <property name="format" value="^[a-z][a-z0-9][a-zA-Z0-9]*$"/>
   <property name="accessModifiers" value="public"/>
   <message key="name.invalidPattern"
     value="Parameter name ''{0}'' must match pattern ''{1}''"/>
 </module>

    Code Example:

     class MyClass {
   void method1(int v1) {} // OK
   protected method2(int V2) {} // violation, Parameter name 'V2'
                                // must match pattern '^[a-z]([a-z0-9][a-zA-Z0-9]*)?$'
   private method3(int a) {} // OK
   public method4(int b) {} // violation, Parameter name 'b'
                            // must match pattern '^[a-z][a-z0-9][a-zA-Z0-9]*$'
 }

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • name.invalidPattern
    Since:
    3.0

    • Constructor Detail

      • ParameterNameCheck

        public ParameterNameCheck()
        Creates a new ParameterNameCheck instance.

    • Method Detail

      • setIgnoreOverridden

        public void setIgnoreOverridden​(boolean ignoreOverridden)
        Setter to allows to skip methods with Override annotation from validation.
        Parameters:
        ignoreOverridden - Flag for skipping methods with Override annotation.

      • setAccessModifiers

        public void setAccessModifiers​(AccessModifierOption... accessModifiers)
        Setter to access modifiers of methods where parameters are checked.
        Parameters:
        accessModifiers - access modifiers of methods which should be checked.

      • getDefaultTokens

        public int[] getDefaultTokens()
        Description copied from class: AbstractCheck
        Returns the default token a check is interested in. Only used if the configuration for a check does not define the tokens.
        Specified by:
        getDefaultTokens in class AbstractCheck
        Returns:
        the default tokens
        See Also:
        TokenTypes

      • getAcceptableTokens

        public int[] getAcceptableTokens()
        Description copied from class: AbstractCheck
        The configurable token set. Used to protect Checks against malicious users who specify an unacceptable token set in the configuration file. The default implementation returns the check's default tokens.
        Specified by:
        getAcceptableTokens in class AbstractCheck
        Returns:
        the token set this check is designed for.
        See Also:
        TokenTypes

      • getRequiredTokens

        public int[] getRequiredTokens()
        Description copied from class: AbstractCheck
        The tokens that this check must be registered for.
        Specified by:
        getRequiredTokens in class AbstractCheck
        Returns:
        the token set this must be registered for.
        See Also:
        TokenTypes

      • mustCheckName

        protected boolean mustCheckName​(DetailAST ast)
        Description copied from class: AbstractNameCheck
        Decides whether the name of an AST should be checked against the format regexp.
        Specified by:
        mustCheckName in class AbstractNameCheck
        Parameters:
        ast - the AST to check.
        Returns:
        true if the IDENT subnode of ast should be checked against the format regexp.