Implemented in the Cúram client application.
It specifies a regular expression that the string value must match before it can be sent to the server. The regular expression must match the whole string, not just a portion of it. The regular expression syntax is the standard Java regular expression syntax used in Java 1.5. Full details on the supported syntax for these regular expressions can be found in the JavaDoc documentation for the java.util.regex.Pattern class supplied with your Java SDK.