question: public boolean validChar ( String c ) { if ( getConstraint ( ) == TextArea . NUMERIC ) { if ( c . charAt ( 0 ) < '0' || c . charAt ( 0 ) > '9' ) { return false ; } } else if ( getConstraint ( ) == TextArea . PHONENUMBER ) { if ( ( c . charAt ( 0 ) < '0' || c . charAt ( 0 ) > '9' ) && c . charAt ( 0 ) != '+' ) { return false ; } } else if ( getConstraint ( ) == TextArea . DECIMAL ) { if ( ( c . charAt ( 0 ) < '0' || c . charAt ( 0 ) > '9' ) && c . charAt ( 0 ) != '+' && c . charAt ( 0 ) != '-' && c . charAt ( 0 ) != '.' ) { return false ; } } return true ; }
target:  Checks if the candidate input is valid for this TextField