How to disable a particular checkstyle rule for a particular line of code?

Question

I have a checkstyle validation rule configured in my project, that prohibits to define class methods with more than 3 input parameters. The rule works fine for my classes, but sometimes I have to extend third-party classes, which do not obey this particular rule.

Is there a possibility to instruct "checkstyle" that a certain method should be silently ignored?

Answer 1

Check out the use of the supressionCommentFilter at http://checkstyle.sourceforge.net/config.html. You'll need to add the module to your checkstyle.xml

<module name="SuppressionCommentFilter"/>

and its configurable. Thus you can add comments to your code to turn off checkstyle (at various levels) and then back on again through the use of comments in your code. E.g.

//CHECKSTYLE:OFF
public void someMethod(String arg1, String arg2, String arg3, String arg4) {
//CHECKSTYLE:ON

See also

<module name="SuppressionFilter">
    <property name="file" value="docs/suppressions.xml"/>
</module>

under the SuppressionFilter section on that same page, which allows you to turn off individual checks for pattern matched resources.

So, if you have in your checkstyle.xml:

<module name="ParameterNumber">
   <property name="id" value="maxParameterNumber"/>
   <property name="max" value="3"/>
   <property name="tokens" value="METHOD_DEF"/>
</module>

You can turn it off in your suppression xml file with:

<suppress id="maxParameterNumber" files="YourCode.java"/>