MethodName

Since Checkstyle 3.0

Description

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.

Properties

name description type default value since
format Specifies valid identifiers. Pattern "^[a-z][a-zA-Z0-9]*$" 3.0
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
}
                  
boolean false 5.0
applyToPublic Controls whether to apply the check to public member. boolean true 5.1
applyToProtected Controls whether to apply the check to protected member. boolean true 5.1
applyToPackage Controls whether to apply the check to package-private member. boolean true 5.1
applyToPrivate Controls whether to apply the check to private member. boolean true 5.1

Examples

To configure the check:

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

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="Checker">
  <module name="TreeWalker">
    <module name="MethodName">
       <property name="format" value="^[a-z](_?[a-zA-Z0-9]+)*$"/>
    </module>
  </module>
</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="Checker">
  <module name="TreeWalker">
    <module name="MethodName">
       <property name="format" value="^[a-zA-Z](_?[a-zA-Z0-9]+)*$"/>
       <property name="allowClassName" value="true"/>
    </module>
  </module>
</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="Checker">
  <module name="TreeWalker">
    <module name="MethodName">
       <property name="format" value="^[a-zA-Z](_?[a-zA-Z0-9]+)*$"/>
       <property name="allowClassName" value="false"/>
    </module>
  </module>
</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="Checker">
  <module name="TreeWalker">
    <module name="MethodName">
       <property name="format" value="^[a-z](_?[a-zA-Z0-9]+)*$"/>
       <property name="applyToPublic" value="false"/>
       <property name="applyToProtected" value="false"/>
    </module>
  </module>
</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]+)*$'
  void FourthMethod() {} // violation, name 'FourthMethod' must match
                         // pattern '^[a-z](_?[a-zA-Z0-9]+)*$'
}
        

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