Description

Validates abbreviations (consecutive capital letters) length in identifier name, it also allows to enforce camel case naming. Please read more at Google Style Guide to get to know how to avoid long abbreviations in names.

allowedAbbreviationLength specifies how many consecutive capital letters are allowed in the identifier. A value of 3 indicates that up to 4 consecutive capital letters are allowed, one after the other, before a violation is printed. The identifier 'MyTEST' would be allowed, but 'MyTESTS' would not be. A value of 0 indicates that only 1 consecutive capital letter is allowed. This is what should be used to enforce strict camel casing. The identifier 'MyTest' would be allowed, but 'MyTEst' would not be.

Properties

Examples

Default configuration

<module name="AbbreviationAsWordInName"/>
       

To configure to check all variables and identifiers (including ones with the static modifier) and enforce no abbreviations (essentially camel case) except for words like 'XML' and 'URL'.

Configuration:

<module name="AbbreviationAsWordInName">
  <property name="tokens" value="VARIABLE_DEF,CLASS_DEF"/>
  <property name="ignoreStatic" value="false"/>
  <property name="allowedAbbreviationLength" value="0"/>
  <property name="allowedAbbreviations" value="XML,URL"/>
</module>
        

Example:

public class MyClass { // OK
  int firstNum; // OK
  int secondNUM; // violation, it allowed only 1 consecutive capital letter
  static int thirdNum; // OK, the static modifier would be checked
  static int fourthNUm; // violation, the static modifier would be checked,
                        // and only 1 consecutive capital letter is allowed
  String firstXML; // OK, XML abbreviation is allowed
  String firstURL; // OK, URL abbreviation is allowed
}
          

To configure to check variables, excluding fields with the static modifier, and allow abbreviations up to 2 consecutive capital letters ignoring the longer word 'CSV'.

Configuration:

<module name="AbbreviationAsWordInName">
  <property name="tokens" value="VARIABLE_DEF"/>
  <property name="ignoreStatic" value="true"/>
  <property name="allowedAbbreviationLength" value="1"/>
  <property name="allowedAbbreviations" value="CSV"/>
</module>
          

Example:

public class MyClass { // OK, ignore checking the class name
  int firstNum; // OK, abbreviation "N" is of allowed length 1
  int secondNUm; // OK
  int secondMYNum; // violation, found "MYN" but only
                   // 2 consecutive capital letters are allowed
  int thirdNUM; // violation, found "NUM" but it is allowed
                // only 2 consecutive capital letters
  static int fourthNUM; // OK, variables with static modifier
                        // would be ignored
  String firstCSV; // OK, CSV abbreviation is allowed
  String firstXML; // violation, XML abbreviation is not allowed
}
          

Example of Usage

• Google Style
• Checkstyle Style

Violation Messages

• abbreviation.as.word

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

Description

Ensures that the names of abstract classes conforming to some regular expression and check that abstract modifier exists.

Rationale: Abstract classes are convenience base class implementations of interfaces, not types as such. As such they should be named to indicate this. Also if names of classes starts with 'Abstract' it's very convenient that they will have abstract modifier.

Properties

Examples

The following example shows how to configure the AbstractClassName to checks names, but ignore missing abstract modifiers:

Configuration:

<module name="AbstractClassName">
  <property name="ignoreModifier" value="true"/>
</module>
        

Example:

abstract class AbstractFirstClass {} // OK
abstract class SecondClass {} // violation, it should match the pattern "^Abstract.+$"
class AbstractThirdClass {} // OK, no "abstract" modifier
          

Example of Usage

• Checkstyle Style

Violation Messages

• illegal.abstract.class.name
• no.abstract.class.modifier

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

Description

Checks that catch parameter names conform to a specified pattern.

Default pattern has the following characteristic:

• allows names beginning with two lowercase letters followed by at least one uppercase or lowercase letter
• allows e abbreviation (suitable for exceptions end errors)
• allows ex abbreviation (suitable for exceptions)
• allows t abbreviation (suitable for throwables)
• prohibits numbered abbreviations like e1 or t2
• prohibits one letter prefixes like pException
• prohibits two letter abbreviations like ie or ee
• prohibits any other characters than letters

Properties

Examples

An example of how to configure the check is:

<module name="CatchParameterName"/>
        

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

Configuration:

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

Example:

public class MyTest {
  public void myTest() {
    try {
      // ...
    } catch (ArithmeticException ex) { //OK
      // ...
    } catch (ArrayIndexOutOfBoundsException ex2) { //OK
      // ...
    } catch (IOException thirdException) { //OK
      // ...
    } catch (Exception FourthException) { // violation, the initial letter
                                          // should be lowercase
      // ...
    }
  }
}
          

Example of Usage

• Google Style
• Checkstyle Style

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

Description

Checks that class type parameter names conform to a specified pattern.

Properties

Examples

An example of how to configure the check is:

<module name="ClassTypeParameterName"/>
        

An example of how to configure the check for names that are only a single letter is:

Configuration:

<module name="ClassTypeParameterName">
  <property name="format" value="^[a-zA-Z]$"/>
</module>
        

Example:

class MyClass1<T> {} // OK
class MyClass2<t> {} // OK
class MyClass3<abc> {} // violation, the class type parameter
                             // name should match the regular expression "^[a-zA-Z]$"
         

Example of Usage

• Google Style
• Checkstyle Style

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

Description

Checks that constant names conform to a specified pattern. A constant is a static and final field or an interface/annotation field, except serialVersionUID and serialPersistentFields.

Properties

Examples

An example of how to configure the check is:

<module name="ConstantName"/>
        

The following configuration apart from names allowed by default allows log or logger:

<module name="ConstantName">
  <property name="format"
    value="^log(ger)?$|^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$"/>
</module>
        

Code Example:

class MyClass {
  final static int log = 10; // OK
  final static int logger = 50; // OK
  final static int logMYSELF = 10; // violation, name 'logMYSELF' must match
                                   // pattern '^log(ger)?$|^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$'
  final static int loggerMYSELF = 5; // violation, name 'loggerMYSELF' must match
                                     // pattern '^log(ger)?$|^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$'
  final static int MYSELF = 100; // OK
  final static int myselfConstant = 1; // violation, name 'myselfConstant' must match pattern
                                       // '^log(ger)?$|^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$'
}
          

The following configuration skip validation on public constant field and protected constant field.

<module name="ConstantName">
  <property name="applyToPublic" value="false"/>
  <property name="applyToProtected" value="false"/>
</module>
          

Code Example:

class MyClass {
  public final static int firstConstant = 10; // OK
  protected final static int secondConstant = 100; // OK
  final static int thirdConstant = 1000; // violation, name 'thirdConstant' must
                                         // match pattern '^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$'
  private final static int fourthConstant = 50; // violation, name 'fourthConstant' must match
                                                // pattern '^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$'
}
          

Example of Usage

• Sun Style
• Checkstyle Style

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

Description

Checks that interface type parameter names conform to a specified pattern.

Properties

Examples

An example of how to configure the check is:

<module name="InterfaceTypeParameterName"/>
        

Code Example:

interface FirstInterface<T> {} // OK
interface SecondInterface<t> {} // violation, name 't' must match pattern '^[A-Z]$'
          

An example of how to configure the check for names that are only a single letter is:

<module name="InterfaceTypeParameterName">
   <property name="format" value="^[a-zA-Z]$"/>
</module>
        

Code Example:

interface FirstInterface<T> {} // OK
interface SecondInterface<t> {} // OK
interface ThirdInterface<type> {} // violation, name 'type' must
                                        // match pattern '^[a-zA-Z]$'
          

Example of Usage

• Google Style
• Checkstyle Style

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

Description

Checks lambda parameter names.

Properties

Examples

An example of how to configure the check is:

<module name="LambdaParameterName"/>
        

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

<module name="LambdaParameterName">
  <property name="format" value="^[a-z]([a-zA-Z]+)*$"/>
</module>
        

Example of checking with this config:

public class TestClass {

    Function<String, String> function1 = str -> str.toUpperCase().trim();

    Function<String, String> function2 = _s -> _s.trim().toUpperCase(); // violation

    public boolean testMethod(String sentence) {
        return Stream.of(sentence.split(" "))
            .map(word -> word.trim())
            .anyMatch(Word -> "in".equals(Word)); // violation
    }

}
        

Example of Usage

• Google Style
• Checkstyle Style

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

Description

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.

Properties

Examples

An example of how to configure the check is:

<module name="LocalFinalVariableName"/>
        

An example of how to configure the check for names that are only upper case letters and digits is:

<module name="LocalFinalVariableName">
  <property name="format" value="^[A-Z][A-Z0-9]*$"/>
</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="LocalFinalVariableName">
  <property name="format" value="^[A-Z][A-Z0-9]*$"/>
  <property name="tokens" value="PARAMETER_DEF,RESOURCE">
</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
    }
  }
}
          

Example of Usage

• Sun Style
• Checkstyle Style

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

Description

Checks that local, non-final variable names conform to a specified pattern. A catch parameter is considered to be a local variable.

Properties

for (int i = 1; i < 10; i++) { // OK
    int j = 1; // violation
}
for (int K = 1; K < 10; K++) { // OK
    int j = 1; // violation
}
List list = new ArrayList();
for (Object o : list) { // OK
    int j = 1; // violation
}
for (Object O : list) { // OK
    int j = 1; // violation
}
                

Examples

An example of how to configure the check is:

<module name="LocalVariableName"/>
        

Code Example:

class MyClass {
  void MyMethod() {
    for (int var = 1; var < 10; var++) {} // OK
    for (int VAR = 1; VAR < 10; VAR++) {} // violation, name 'VAR' must match
                                          // pattern '^[a-z][a-zA-Z0-9]*$'
    for (int i = 1; i < 10; i++) {} // OK
    for (int var_1 = 0; var_1 < 10; var_1++) {} // violation, name 'var_1' must match
                                                   // pattern '^[a-z][a-zA-Z0-9]*$'
  }
}
          

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

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

Code Example:

class MyClass {
  void MyMethod() {
    for (int var = 1; var < 10; var++) {} // OK
    for (int VAR = 1; VAR < 10; VAR++) {} // violation, name 'VAR' must match
                                             // pattern '^[a-z](_?[a-zA-Z0-9]+)*$'
    for (int i = 1; i < 10; i++) {} // OK
    for (int var_1 = 0; var_1 < 10; var_1++) {} // OK
  }
}
          

An example of one character variable name in initialization expression(like "i") in FOR loop:

for(int i = 1; i < 10; i++) {}
for(int K = 1; K < 10; K++) {}
List list = new ArrayList();
for (Object o : list) {}
for (Object O : list) {}
          

An example of how to configure the check to allow one character variable name in initialization expressions in FOR loop, where regexp allows 2 or more chars:

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

Code Example:

class MyClass {
  void MyMethod() {
    int good = 1;
    int g = 0; // violation
    for (int v = 1; v < 10; v++) { // OK
        int a = 1; // violation
    }
    for (int V = 1; V < 10; V++) { // OK
        int I = 1; // violation
    }
    List list = new ArrayList();
    for (Object o : list) { // OK
        String a = ""; // violation
    }
    for (Object O : list) { // OK
        String A = ""; // violation
    }
  }
}
          

An example of how to configure the check to that all variables have 3 or more chars in name:

<module name="LocalVariableName">
  <property name="format" value="^[a-z][_a-zA-Z0-9]{2,}$"/>
</module>
        

Code Example:

class MyClass {
  void MyMethod() {
    int goodName = 0;
    int i = 1; // violation
    for (int var = 1; var < 10; var++) { //OK
      int j = 1; // violation
    }
  }
}
          

Example of Usage

• Google Style
• Sun Style
• Checkstyle Style

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

Description

Checks that instance variable names conform to a specified pattern.

Properties

Examples

An example of how to configure the check is:

<module name="MemberName"/>
        

Code Example:

class MyClass {
  public int num1; // OK
  protected int num2; // OK
  int num3; // OK
  private int num4; // OK

  public int NUM1; // violation, name 'NUM1'
                   // must match pattern '^[a-z][a-zA-Z0-9]*$'
  protected int NUM2; // violation, name 'NUM2'
                      // must match pattern '^[a-z][a-zA-Z0-9]*$'
  int NUM3; // violation, name 'NUM3'
            // must match pattern '^[a-z][a-zA-Z0-9]*$'
  private int NUM4; // violation, name 'NUM4'
                    // must match pattern '^[a-z][a-zA-Z0-9]*$'
}
          

An example of how to configure the check for names that begin with "m", followed by an upper case letter, and then letters and digits. Also, suppress the check from being applied to protected and package-private member:

<module name="MemberName">
  <property name="format" value="^m[A-Z][a-zA-Z0-9]*$"/>
  <property name="applyToProtected" value="false"/>
  <property name="applyToPackage" value="false"/>
</module>
        

Code Example:

class MyClass {
  public int num1; // violation, name 'num1'
                   // must match pattern '^m[A-Z][a-zA-Z0-9]*$'
  protected int num2; // OK
  int num3; // OK
  private int num4; // violation, name 'num4'
                    // must match pattern '^m[A-Z][a-zA-Z0-9]*$'
}
          

An example of how to suppress the check which is applied to public and private member:

<module name="MemberName">
  <property name="applyToPublic" value="false"/>
  <property name="applyToPrivate" value="false"/>
</module>
          

Code Example:

class MyClass {
  public int NUM1; // OK
  protected int NUM2; // violation, name 'NUM2'
                      // must match pattern '^[a-z][a-zA-Z0-9]*$'
  int NUM3; // violation, name 'NUM3'
            // must match pattern '^[a-z][a-zA-Z0-9]*$'
  private int NUM4; // OK
}
          

Example of Usage

• Google Style
• Sun Style
• Checkstyle Style

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

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

class MyClass {
    public void MyClass() {} //this is a method
    public MyClass() {} //this is a constructor
}
                

Examples

An example of how to configure the check is:

<module name="MethodName"/>
        

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]+)*$'
  void FourthMethod() {} // violation, name 'FourthMethod' must match
                         // pattern '^[a-z](_?[a-zA-Z0-9]+)*$'
}
          

Example of Usage

• Google Style
• Sun Style
• Checkstyle Style

Violation Messages

• method.name.equals.class.name
• 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

Description

Checks that method type parameter names conform to a specified pattern.

Properties

Examples

An example of how to configure the check is:

<module name="MethodTypeParameterName"/>
        

Code Example:

class MyClass {
  public <T> void method1() {} // OK
  public <a> void method2() {} // violation,  name 'a' must match pattern '^[A-Z]$'
  public <K, V> void method3() {} // OK
  public <k, V> void method4() {} // violation, name 'k' must match pattern '^[A-Z]$'
}
          

An example of how to configure the check for names that are only a single letter is:

<module name="MethodTypeParameterName">
   <property name="format" value="^[a-zA-Z]$"/>
</module>
        

Code Example:

class MyClass {
  public <T> void method1() {} // OK
  public <a> void method2() {} // OK
  public <K, V> void method3() {} // OK
  public <k, V> void method4() {} // OK
}
          

Example of Usage

• Google Style
• Checkstyle Style

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

Description

Checks that package names conform to a specified pattern.

The default value of format for module PackageName has been chosen to match the requirements in the Java Language specification and the Sun coding conventions. However both underscores and uppercase letters are rather uncommon, so most configurations should probably assign value ^[a-z]+(\.[a-z][a-z0-9]*)*$ to format for module PackageName.

Properties

Examples

An example of how to configure the check is:

<module name="PackageName"/>
        

Code Example:

package com; // OK
package COM; // violation, name 'COM' must match pattern '^[a-z]+(\.[a-zA-Z_][a-zA-Z0-9_]*)*$'
package com.checkstyle.checks; // OK
package com.A.checkstyle.checks; // OK
package com.checkstyle1.checks; // OK
package com.checkSTYLE.checks; // OK
package com._checkstyle.checks_; // OK
          

An example of how to configure the check to ensure with packages start with a lowercase letter and only contains lowercase letters or numbers is:

<module name="PackageName">
  <property name="format"
    value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
</module>
        

Code Example:

package com; // OK
package COM; // violation, name 'COM' must match pattern '^[a-z]+(\.[a-z][a-z0-9]*)*$'
package com.checkstyle.checks; // OK
package com.A.checkstyle.checks; // violation, name 'com.A.checkstyle' must match
                                 // pattern '^[a-z]+(\.[a-z][a-z0-9]*)*$'
package com.checkstyle1.checks; // OK
package com.checkSTYLE.checks; // violation, name 'com.checkSTYLE.checks' must
                               // match pattern '^[a-z]+(\.[a-z][a-z0-9]*)*$'
package com._checkstyle.checks_; // violation, name 'com._checkstyle.checks_' must match
                                 // pattern '^[a-z]+(\.[a-z][a-z0-9]*)*$'
          

Example of Usage

• Google Style
• Sun Style
• Checkstyle Style

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

Description

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.

Properties

@Override
public boolean equals(Object o) {
  return super.equals(o);
}
                  

Examples

An example of how to configure the check:

<module name="ParameterName"/>
        

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>
        

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>
          

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>
        

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>
        

Example of Usage

• Google Style
• Sun Style
• Checkstyle Style

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

Description

Checks that static, non-final variable names conform to a specified pattern.

Properties

Examples

An example of how to configure the check is:

<module name="StaticVariableName"/>
        

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

Example of Usage

• Sun Style
• Checkstyle Style

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

Description

Checks that type names conform to a specified pattern.

Properties

Examples

An example of how to configure the check is:

<module name="TypeName"/>
        

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

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

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

Example of Usage

• Google Style
• Sun Style
• Checkstyle Style

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