TypeName

Since Checkstyle 3.0

Description

Checks that type names conform to a specified pattern.

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-zA-Z0-9]*$"`	3.0
tokens	tokens to check	subset of tokens CLASS_DEF , INTERFACE_DEF , ENUM_DEF , ANNOTATION_DEF , RECORD_DEF .	CLASS_DEF , INTERFACE_DEF , ENUM_DEF , ANNOTATION_DEF , RECORD_DEF .	3.0

Examples

To configure the check:


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

Code Example:


class Example1 {
  public interface FirstName {}
  protected class SecondName {}
  enum Third_Name {} // violation 'Name 'Third_Name' must match pattern'
  private class FourthName_ {} // violation 'Name 'FourthName_' must match pattern'
}

An example of how to configure the check for names that begin with a lower case letter, followed by letters, digits, and underscores. Also, suppress the check from being applied to protected and private type:


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

Code Example:


class Example2 {   // violation 'Name 'Example2' must match pattern'
  public interface firstName {}
  public class SecondName {} // violation 'Name 'SecondName' must match pattern'
  protected class ThirdName {}
  private class FourthName {}
}

The following configuration element ensures that interface names begin with "I_", followed by letters and digits:


<module name="Checker">
  <module name="TreeWalker">
    <module name="TypeName">
      <property name="format"
        value="^I_[a-zA-Z0-9]*$"/>
      <property name="tokens"
        value="INTERFACE_DEF"/>
    </module>
  </module>
</module>

Code Example:


class Example3 {
  public interface I_firstName {}
  interface SecondName {} // violation 'Name 'SecondName' must match pattern'
}

Example of Usage

Violation Messages

name.invalidPattern

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