assert null != prefix : "The prefix string must be not null, use an empty string instead";
assert null != suffix : "The postfix string must be not null, use an empty string instead";
String result = "(";
Iterator iterator = stmnt.iterator();
while(iterator.hasNext()) {
DataQueryStatement subStatement = iterator.next();
result += prefix + statementAdapter(subStatement) + suffix;
}
return result.substring(0, result.length() - suffix.length()) + ")";