/**
* Builds a new Record from its textual representation
*
* @param name The owner name of the record.
* @param type The record's type.
* @param dclass The record's class.
* @param ttl The record's time to live.
* @param st A tokenizer containing the textual representation of the rdata.
* @param origin The default origin to be appended to relative domain names.
* @return The new record
* @throws IOException The text format was invalid.
*/
public static Record fromString(
Name name, int type, int dclass, long ttl, Tokenizer st, Name origin) throws IOException {
Record rec;
if (!name.isAbsolute()) throw new RelativeNameException(name);
Type.check(type);
DClass.check(dclass);
TTL.check(ttl);
Tokenizer.Token t = st.get();
if (t.type == Tokenizer.IDENTIFIER && t.value.equals("\\#")) {
int length = st.getUInt16();
byte[] data = st.getHex();
if (data == null) {
data = new byte[0];
}
if (length != data.length)
throw st.exception("invalid unknown RR encoding: " + "length mismatch");
DNSInput in = new DNSInput(data);
return newRecord(name, type, dclass, ttl, length, in);
}
st.unget();
rec = getEmptyRecord(name, type, dclass, ttl, true);
rec.rdataFromString(st, origin);
t = st.get();
if (t.type != Tokenizer.EOL && t.type != Tokenizer.EOF) {
throw st.exception("unexpected tokens at end of record");
}
return rec;
}
/**
* Determines if two Records are identical. This compares the name, type, class, and rdata (with
* names canonicalized). The TTLs are not compared.
*
* @param arg The record to compare to
* @return true if the records are equal, false otherwise.
*/
public boolean equals(Object arg) {
if (arg == null || !(arg instanceof Record)) return false;
Record r = (Record) arg;
if (type != r.type || dclass != r.dclass || !name.equals(r.name)) return false;
byte[] array1 = rdataToWireCanonical();
byte[] array2 = r.rdataToWireCanonical();
return Arrays.equals(array1, array2);
}
private static final Record getEmptyRecord(
Name name, int type, int dclass, long ttl, boolean hasData) {
Record rec;
if (hasData) rec = getTypedObject(type).getObject();
else rec = new EmptyRecord();
rec.name = name;
rec.type = type;
rec.dclass = dclass;
rec.ttl = ttl;
return rec;
}
private static Record newRecord(
Name name, int type, int dclass, long ttl, int length, DNSInput in) throws IOException {
Record rec;
int recstart;
rec = getEmptyRecord(name, type, dclass, ttl, in != null);
if (in != null) {
if (in.remaining() < length) throw new WireParseException("truncated record");
in.setActive(length);
rec.rrFromWire(in);
if (in.remaining() > 0) throw new WireParseException("invalid record length");
in.clearActive();
}
return rec;
}
/**
* Compares this Record to another Object.
*
* @param o The Object to be compared.
* @return The value 0 if the argument is a record equivalent to this record; a value less than 0
* if the argument is less than this record in the canonical ordering, and a value greater
* than 0 if the argument is greater than this record in the canonical ordering. The canonical
* ordering is defined to compare by name, class, type, and rdata.
* @throws ClassCastException if the argument is not a Record.
*/
public int compareTo(Object o) {
Record arg = (Record) o;
if (this == arg) return (0);
int n = name.compareTo(arg.name);
if (n != 0) return (n);
n = dclass - arg.dclass;
if (n != 0) return (n);
n = type - arg.type;
if (n != 0) return (n);
byte[] rdata1 = rdataToWireCanonical();
byte[] rdata2 = arg.rdataToWireCanonical();
for (int i = 0; i < rdata1.length && i < rdata2.length; i++) {
n = (rdata1[i] & 0xFF) - (rdata2[i] & 0xFF);
if (n != 0) return (n);
}
return (rdata1.length - rdata2.length);
}
private static final Record getTypedObject(int type) {
if (type < 0 || type > knownRecords.length) return unknownRecord.getObject();
if (knownRecords[type] != null) return knownRecords[type];
/* Construct the class name by putting the type before "Record". */
String s =
Record.class.getPackage().getName() + "." + Type.string(type).replace('-', '_') + "Record";
try {
Class c = Class.forName(s);
Constructor m = c.getDeclaredConstructor(emptyClassArray);
knownRecords[type] = (Record) m.newInstance(emptyObjectArray);
} catch (ClassNotFoundException e) {
/* This is normal; do nothing */
} catch (Exception e) {
if (Options.check("verbose")) System.err.println(e);
}
if (knownRecords[type] == null) knownRecords[type] = unknownRecord.getObject();
return knownRecords[type];
}
/**
* Creates a new record identical to the current record, but with a different class and ttl. This
* is most useful for dynamic update.
*/
Record withDClass(int dclass, long ttl) {
Record rec = cloneRecord();
rec.dclass = dclass;
rec.ttl = ttl;
return rec;
}
/**
* Creates a new record identical to the current record, but with a different name. This is most
* useful for replacing the name of a wildcard record.
*/
public Record withName(Name name) {
if (!name.isAbsolute()) throw new RelativeNameException(name);
Record rec = cloneRecord();
rec.name = name;
return rec;
}
/**
* Determines if two Records could be part of the same RRset. This compares the name, type, and
* class of the Records; the ttl and rdata are not compared.
*/
public boolean sameRRset(Record rec) {
return (getRRsetType() == rec.getRRsetType() && dclass == rec.dclass && name.equals(rec.name));
}