Each of these naming modules validates identifiers for particular code elements. Valid identifiers for a naming module are specified by its format property. The value of format is a regular expression for valid identifiers.
Since Checkstyle 5.8
The Check validate 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.
| name | description | type | default value | since |
|---|---|---|---|---|
| allowedAbbreviationLength | indicates on the number of consecutive capital letters allowed in targeted identifiers (abbreviations in the classes, interfaces, variables and methods names, ... ). | Integer | 3 | 5.8 |
| allowedAbbreviations | list of abbreviations that must be skipped for checking. Abbreviations should be separated by comma, no spaces are allowed. | String Set | {} | 5.8 |
| ignoreFinal | allow to skip variables with final modifier. | Boolean | true | 5.8 |
| ignoreStatic | allow to skip variables with static modifier. | Boolean | true | 5.8 |
| ignoreOverriddenMethods | Allows to ignore methods tagged with @Override annotation (that usually mean inherited name). | Boolean | true | 5.8 |
| tokens | tokens to check | subset of tokens CLASS_DEF, INTERFACE_DEF, ENUM_DEF, ANNOTATION_DEF, ANNOTATION_FIELD_DEF, PARAMETER_DEF, VARIABLE_DEF, METHOD_DEF, ENUM_CONSTANT_DEF. | CLASS_DEF, INTERFACE_DEF, ENUM_DEF, ANNOTATION_DEF, ANNOTATION_FIELD_DEF, PARAMETER_DEF, VARIABLE_DEF, METHOD_DEF. | 5.8 |
Default configuration
<module name="AbbreviationAsWordInName"/>
To configure to check variables and classes identifiers, do not ignore variables with static modifier and allow no abbreviations (enforce camel case phrase) and allow no abbreviations to use (camel case phrase) and allow XML and URL abbreviations.
<module name="AbbreviationAsWordInName">
<property name="tokens" value="VARIABLE_DEF,CLASS_DEF"/>
<property name="ignoreStatic" value="false"/>
<property name="allowedAbbreviationLength" value="1"/>
<property name="allowedAbbreviations" value="XML,URL"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^Abstract.+$" | 3.2 |
| ignoreModifier | Controls whether to ignore checking for the abstract modifier on classes that match the name. | Boolean | false | 5.3 |
| ignoreName | Controls whether to ignore checking the name. Realistically only useful if using the check to identify that match name and do not have the abstract modifier. name. | Boolean | false | 5.3 |
The following example shows how to configure the AbstractClassName to checks names, but ignore missing abstract modifiers:
<module name="AbstractClassName">
<property name="ignoreModifier" value="true"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 6.14
Checks that catch parameter names conform to a format specified by the format property. Default pattern has the following characteristic:
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^(e|t|ex|[a-z][a-z][a-zA-Z]+)$" | 6.14 |
To configure the check:
<module name="CatchParameterName"/>
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="CatchParameterName">
<property name="format" value="^[a-z][a-zA-Z0-9]+$"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[A-Z]$" | 5.0 |
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$" | 3.0 |
| applyToPublic | Controls whether to apply the check to public member. | Boolean | true | 5.0 |
| applyToProtected | Controls whether to apply the check to protected member. | Boolean | true | 5.0 |
| applyToPackage | Controls whether to apply the check to package-private member. | Boolean | true | 5.0 |
| applyToPrivate | Controls whether to apply the check to private member. | Boolean | true | 5.0 |
Property format in module ConstantName is used to specify names to be allowed. The following configuration apart from names allowed by default allows log or logger:
<module name="ConstantName">
<property name="format"
value="^log(ger)?|[A-Z][A-Z0-9]*(_[A-Z0-9]+)*$"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[A-Z]$" | 5.8 |
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 3.0
Validates identifiers for local, final variables, including catch parameters and resources in try statements.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[a-z][a-zA-Z0-9]*$" | 3.0 |
| tokens | tokens to check | subset of tokens VARIABLE_DEF, PARAMETER_DEF, RESOURCE. | VARIABLE_DEF, PARAMETER_DEF, RESOURCE. | 3.0 |
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 3.0
Checks that local, non-final variable names conform to a format specified by the format property.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[a-z][a-zA-Z0-9]*$" | 3.0 |
| allowOneCharVarInForLoop |
Allow one character variable name in initialization expressions in FOR loop. For example:
for (int i = 1; i < 10; i++) {}
|
Boolean | false | 5.8 |
To configure the check to use the default configuration:
<module name="LocalVariableName"/>
An example of how to configure the check to allow one character variable name in initialization expressions in FOR loop:
<module name="LocalVariableName">
<property name="allowOneCharVarInForLoop" value="true"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[a-z][a-zA-Z0-9]*$" | 3.0 |
| applyToPublic | Controls whether to apply the check to public member. | Boolean | true | 3.4 |
| applyToProtected | Controls whether to apply the check to protected member. | Boolean | true | 3.4 |
| applyToPackage | Controls whether to apply the check to package-private member. | Boolean | true | 3.4 |
| applyToPrivate | Controls whether to apply the check to private member. | Boolean | true | 3.4 |
This is an example of a configuration of the MemberName module to ensure that member identifiers begin with 'm', followed by an upper case letter, and then letters and digits:
<module name="MemberName">
<property name="format" value="^m[A-Z][a-zA-Z0-9]*$"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[a-z][a-zA-Z0-9]*$" | 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 |
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[A-Z]$" | 5.0 |
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[a-z]+(\.[a-zA-Z_][a-zA-Z0-9_]*)*$" | 3.0 |
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, as in
<module name="PackageName">
<property name="format"
value="^[a-z]+(\.[a-z][a-z0-9]*)*$"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 3.0
Checks that method and catch parameter names conform to a format specified by the format property. By using accessModifiers property it is possible to specify different formats for methods at different visibility levels.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[a-z][a-zA-Z0-9]*$" | 3.0 |
| ignoreOverridden |
Allows to skip methods with Override annotation from validation. For example, the
following method's parameter will be skipped from validation, if
ignoreOverridden is true:
@Override
public boolean equals(Object o) {
return super.equals(o);
}
|
Boolean | false | 6.12.1 |
| accessModifiers | Access modifiers of methods where parameters are checked. | Access Modifier Set | public, protected, package, private | 7.5 |
To configure the check:
<module name="ParameterName"/>
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]*$"/>
<property name="accessModifiers" value="public"/>
<message key="name.invalidPattern"
value="Parameter name ''{0}'' must match pattern ''{1}''"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[a-z][a-zA-Z0-9]*$" | 3.0 |
| applyToPublic | Controls whether to apply the check to public member. | Boolean | true | 5.0 |
| applyToProtected | Controls whether to apply the check to protected member. | Boolean | true | 5.0 |
| applyToPackage | Controls whether to apply the check to package-private member. | Boolean | true | 5.0 |
| applyToPrivate | Controls whether to apply the check to private member. | Boolean | true | 5.0 |
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
Since Checkstyle 3.0
Validates identifiers for classes, interfaces, enums, and annotations.
| name | description | type | default value | since |
|---|---|---|---|---|
| format | Specifies valid identifiers. | Regular Expression | "^[A-Z][a-zA-Z0-9]*$" | 3.0 |
| applyToPublic | Controls whether to apply the check to public member. | Boolean | true | 5.0 |
| applyToProtected | Controls whether to apply the check to protected member. | Boolean | true | 5.0 |
| applyToPackage | Controls whether to apply the check to package-private member. | Boolean | true | 5.0 |
| applyToPrivate | Controls whether to apply the check to private member. | Boolean | true | 5.0 |
| tokens | tokens to check | subset of tokens CLASS_DEF, INTERFACE_DEF, ENUM_DEF, ANNOTATION_DEF. | CLASS_DEF, INTERFACE_DEF, ENUM_DEF, ANNOTATION_DEF. | 3.0 |
The following configuration element ensures that interface names begin with "I_", followed by letters and digits:
<module name="TypeName">
<property name="format"
value="^I_[a-zA-Z0-9]*$"/>
<property name="tokens"
value="INTERFACE_DEF"/>
</module>
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.