question: public boolean isValidRegularExpression ( final String expressionString ) { Check . notNull ( expressionString , "expressionString" ) ; if ( expressionString . length ( ) == 0 ) { return false ; } try { Pattern . compile ( expressionString , compileFlags ) ; return true ; } catch ( final PatternSyntaxException e ) { return false ; } }
target:  Tests whether the given expression string is a valid expression for inclusion in this table. This is provided so other controls can validate input before inserting into the table using the same rules this table uses for cell modification. <p> Empty strings are not valid.