Class MethodNameCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable

    public class MethodNameCheck
    extends AbstractAccessControlNameCheck

    Checks that method names conform to a specified pattern.

    Also, checks if a method name has the same name as the residing class. The default is false (it is not allowed). It is legal in Java to have method with the same name as a class. As long as a return type is specified it is a method and not a constructor which it could be easily confused as. Does not check-style the name of an overridden methods because the developer does not have a choice in renaming such methods.

    • Property format - Specifies valid identifiers. Type is java.util.regex.Pattern. Default value is "^[a-z][a-zA-Z0-9]*$".
    • Property allowClassName - Controls whether to allow a method name to have the same name as the residing class name. This is not to be confused with a constructor. An easy mistake is to place a return type on a constructor declaration which turns it into a method. For example:
       class MyClass {
           public void MyClass() {} //this is a method
           public MyClass() {} //this is a constructor
       }
       
      Type is boolean. Default value is false.
    • Property applyToPublic - Controls whether to apply the check to public member. Type is boolean. Default value is true.
    • Property applyToProtected - Controls whether to apply the check to protected member. Type is boolean. Default value is true.
    • Property applyToPackage - Controls whether to apply the check to package-private member. Type is boolean. Default value is true.
    • Property applyToPrivate - Controls whether to apply the check to private member. Type is boolean. Default value is true.

    To configure the check:

     <module name="MethodName"/>
     

    Code Example:

     class MyClass {
       public void firstMethod1() {} // OK
       protected void secondMethod() {} // OK
       private void ThirdMethod() {} // violation, method name must match to the
                                     // default pattern '^[a-z][a-zA-Z0-9]*$'
       public void fourth_Method4() {} // violation, method name must match to the
                                      // default pattern '^[a-z][a-zA-Z0-9]*$'
     }
     

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

     <module name="MethodName">
        <property name="format" value="^[a-z](_?[a-zA-Z0-9]+)*$"/>
     </module>
     

    Code Example:

     class MyClass {
       public void myMethod() {} // OK
       public void MyMethod() {} // violation, name "MyMethod"
                                 // should match the pattern "^[a-z](_?[a-zA-Z0-9]+)*$"
     }
     

    An example of how to configure the check to allow method names to be equal to the residing class name is:

     <module name="MethodName">
        <property name="format" value="^[a-zA-Z](_?[a-zA-Z0-9]+)*$"/>
        <property name="allowClassName" value="true"/>
     </module>
     

    Code Example:

     class MyClass {
       public MyClass() {} // OK
       public void MyClass() {} // OK, method Name 'MyClass' is allowed to be
                                // equal to the enclosing class name
     }
     

    An example of how to configure the check to disallow method names to be equal to the residing class name is:

     <module name="MethodName">
        <property name="format" value="^[a-zA-Z](_?[a-zA-Z0-9]+)*$"/>
        <property name="allowClassName" value="false"/>
     </module>
     

    Code Example:

     class MyClass {
       public MyClass() {} // OK
       public void MyClass() {} // violation,  method Name 'MyClass' must not
                                // equal the enclosing class name
     }
     

    An example of how to suppress the check to public and protected methods:

     <module name="MethodName">
        <property name="format" value="^[a-z](_?[a-zA-Z0-9]+)*$"/>
        <property name="applyToPublic" value="false"/>
        <property name="applyToProtected" value="false"/>
     </module>
     

    Code Example:

     class MyClass {
       public void FirstMethod() {} // OK
       protected void SecondMethod() {} // OK
       private void ThirdMethod() {} // violation, name 'ThirdMethod' must match
                                     // pattern '^[a-z](_?[a-zA-Z0-9]+)*$'
       void FourthMethod() {} // violation, name 'FourthMethod' must match
                              // pattern '^[a-z](_?[a-zA-Z0-9]+)*$'
     }
     

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • method.name.equals.class.name
    • name.invalidPattern
    Since:
    3.0
    • Field Detail

      • allowClassName

        private boolean allowClassName
        Controls whether to allow a method name to have the same name as the residing class name. This is not to be confused with a constructor. An easy mistake is to place a return type on a constructor declaration which turns it into a method. For example:
         class MyClass {
             public void MyClass() {} //this is a method
             public MyClass() {} //this is a constructor
         }
         
    • Constructor Detail

      • MethodNameCheck

        public MethodNameCheck()
        Creates a new MethodNameCheck instance.
    • Method Detail

      • 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
      • setAllowClassName

        public void setAllowClassName​(boolean allowClassName)
        Setter to controls whether to allow a method name to have the same name as the residing class name. This is not to be confused with a constructor. An easy mistake is to place a return type on a constructor declaration which turns it into a method. For example:
         class MyClass {
             public void MyClass() {} //this is a method
             public MyClass() {} //this is a constructor
         }
         
        Parameters:
        allowClassName - true to allow false to disallow