Patterns in configuration parameters and expressions use the standard Java regular expression Pattern class. For more information on regular expressions, see Oracle's tutorial on Regular Expressions.

Pattern Templates

A regular expression pattern template expresses a transformation to be applied for a matching regular expression pattern. It may contain references to capturing groups within the match result. Each occurrence of $g (where g is an integer value) is substituted by the indexed capturing group in a match result. Capturing group zero "$0" denotes the entire pattern match. A dollar sign or numeral literal immediately following a capture group reference can be included as a literal in the template by preceding it with a backslash ( \ ). Backslash itself must be also escaped in this manner.

More Information

Java Pattern class

Regular Expressions tutorial

Read a different version of :