Class PackageNameCheck

  • All Implemented Interfaces:
    Configurable, Contextualizable

    public class PackageNameCheck
    extends AbstractCheck

    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.

    • Property format - Specifies valid identifiers. Type is java.util.regex.Pattern. Default value is "^[a-z]+(\.[a-zA-Z_][a-zA-Z0-9_]*)*$".

    To configure the check:

     <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]*)*$'
     package com._checkstyle.checks_; // violation, name 'com._checkstyle.checks_' must match
                                      // pattern '^[a-z]+(\.[a-z][a-z0-9]*)*$'
     

    Parent is com.puppycrawl.tools.checkstyle.TreeWalker

    Violation Message Keys:

    • name.invalidPattern
    Since:
    3.0