protected void assertArgumentNotEmpty(String variableName, String value) {
        assertArgumentNotNull(variableName, value);
        if (value.isEmpty()) {
            throw new IllegalArgumentException("The argument '" + variableName + "' should not be empty.");
        }
    }
protected void assertArgumentNotEmpty ( String variableName , String value ) { assertArgumentNotNull ( variableName , value ) ; if ( value . isEmpty ( ) ) { throw new IllegalArgumentException ( "The argument '" + variableName + "' should not be empty." ) ; } }
============