Since Checkstyle 3.2
Ensures that the names of abstract classes conforming to some pattern and
check that abstract
modifier exists.
Rationale: Abstract classes are convenience base class implementations of interfaces. For this reason, it should be made obvious that a given class is abstract by prefacing the class name with 'Abstract'.
name | description | type | default value | since |
---|---|---|---|---|
format | Specify valid identifiers. | Pattern | "^Abstract.+$" |
3.2 |
ignoreModifier | Control whether to ignore checking for the abstract modifier on classes that match the name. |
boolean | false |
5.3 |
ignoreName | Control whether to ignore checking the name. Realistically only useful if using the check to identify that match name and do not have the abstract modifier. |
boolean | false |
5.3 |
To configure the check:
<module name="Checker"> <module name="TreeWalker"> <module name="AbstractClassName"/> </module> </module>
Example:
class Example1 { abstract class AbstractFirst {} abstract class Second {} // violation 'must match pattern' class AbstractThird {} // violation 'must be declared as 'abstract'' class Fourth {} abstract class GeneratorFifth {} // violation above 'must match pattern' class GeneratorSixth {} }
To configure the check so that it check name
but ignore abstract
modifier:
<module name="Checker"> <module name="TreeWalker"> <module name="AbstractClassName"> <property name="ignoreModifier" value="true"/> </module> </module> </module>
Example:
class Example2 { abstract class AbstractFirst {} abstract class Second {} // violation 'must match pattern' class AbstractThird {} class Fourth {} abstract class GeneratorFifth {} // violation above 'must match pattern' class GeneratorSixth {} }
To configure the check to ignore name validation when class declared as 'abstract'
<module name="Checker"> <module name="TreeWalker"> <module name="AbstractClassName"> <property name="ignoreName" value="true"/> </module> </module> </module>
Example:
class Example3 { abstract class AbstractFirst {} abstract class Second {} class AbstractThird {} // violation 'must be declared as 'abstract'' class Fourth {} abstract class GeneratorFifth {} class GeneratorSixth {} }
To configure the check
with format
:
<module name="Checker"> <module name="TreeWalker"> <module name="AbstractClassName"> <property name="format" value="^Generator.+$"/> </module> </module> </module>
Example:
class Example4 { // violation below 'must match pattern' abstract class AbstractFirst {} abstract class Second {} // violation 'must match pattern' class AbstractThird {} class Fourth {} abstract class GeneratorFifth {} class GeneratorSixth {} // violation 'must be declared as 'abstract'' }
All messages can be customized if the default message doesn't suit you. Please see the documentation to learn how to.
com.puppycrawl.tools.checkstyle.checks.naming