public synchronized void
addRecord(Record r, int cred, Object o) {
	Name name = r.getName();
	int type = r.getRRsetType();
	if (!Type.isRR(type))
		return;
	Element element = findElement(name, type, cred);
	if (element == null) {
		CacheRRset crrset = new CacheRRset(r, cred, maxcache);
		addRRset(crrset, cred);
	} else if (element.compareCredibility(cred) == 0) {
		if (element instanceof CacheRRset) {
			CacheRRset crrset = (CacheRRset) element;
			crrset.addRR(r);
		}
	}
}
Adds a record to the Cache.
@param r The record to be added
@param cred The credibility of the record
@param o The source of the record (this could be a Message, for example)
@see Record
src/main/java/core/org/xbill/DNS/Cache.java