code: /*xml
  <module name="Checker">
    <module name="TreeWalker">
      <module name="AbstractClassName">
        <property name="format" value="^Generator.+$"/>
      </module>
    </module>
  </module>
  
  
  */
  
  package com.puppycrawl.tools.checkstyle.checks.naming.abstractclassname;
  
  // xdoc section -- start
  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''
  }
  // xdoc section -- end
  