@Override
  public void transientInit(Configuration conf) throws HiveException {
    super.transientInit(conf);

    checker = createChecker(pattern);
  }
An abstract class for LIKE and REGEXP expressions. LIKE and REGEXP expression share similar
functions, but they have different grammars. AbstractFilterStringColLikeStringScalar class
provides shared classes and methods. Each subclass handles its grammar.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/AbstractFilterStringColLikeStringScalar.java