import org.xbill.DNS.Cache; //导入依赖的package包/类
private Message getCached(Message query) {
	Cache cache = getCache();
	if (cache == null)
		return null;

	Record question = query.getQuestion();
	RRset[] rrsets = cache.findAnyRecords(question.getName(), question.getType());
	if (rrsets == null)
		return null;

	Message msg = new Message();
	for (RRset rrset : rrsets) {
		@SuppressWarnings("unchecked")
		Iterator<Record> recordsIter = rrset.rrs();
		while (recordsIter.hasNext()) {
			msg.addRecord(recordsIter.next(), Section.ANSWER);
		}
	}
	return msg;
}
 

import org.xbill.DNS.Cache; //导入依赖的package包/类
public DNSCacheManager() {
    setProperty(new CollectionProperty(SERVERS, new ArrayList<String>()));
    //disabling cache
    lookupCache = new Cache();
    lookupCache.setMaxCache(0);
    lookupCache.setMaxEntries(0);
}
 

import org.xbill.DNS.Cache; //导入依赖的package包/类
/**
 * Overloaded constructor taking as argument Cache size and TTL.
 *
 * @param cacheSize Unsigned <code>int</code> defining the Cache size
 * @param cacheTTL Unsigned <code>int</code> defining the Cache TTL
 */
public DnsServicesDiscovery(int cacheSize, int cacheTTL)
{
    this.anyClassCache = new Cache(DClass.ANY);
    this.anyClassCache.setMaxEntries(cacheSize);
    this.anyClassCache.setMaxNCache(cacheTTL);
    this.helper = this.new ServicesLookupHelper();
    this.errorsTrace = new ThreadLocal<Map<String, StatusCode>>() {
        @Override
        protected Map<String, StatusCode> initialValue() {
            return new LinkedHashMap<>();
        }
    };
}
 

import org.xbill.DNS.Cache; //导入依赖的package包/类
private Lookup doLookup(final SimpleResolver resolver, String hostname)
    throws TextParseException {
  final Cache cache = new Cache();
  final Lookup lookup = new Lookup(new Name(hostname), org.xbill.DNS.Type.SRV);
  lookup.setResolver(resolver);
  lookup.setCache(cache);
  return lookup;
}
 

import org.xbill.DNS.Cache; //导入依赖的package包/类
private void addCached(Message msg) {
	Cache cache = getCache();
	if (cache != null)
		cache.addMessage(msg);
}
 

import org.xbill.DNS.Cache; //导入依赖的package包/类
@PostConstruct
public void init() throws Exception {
    logger.debug("DNSService init...");

    // If no DNS servers were configured, default to local host
    if (dnsServers.isEmpty()) {
        try {
            dnsServers.add(InetAddress.getLocalHost().getHostName());
        } catch (UnknownHostException ue) {
            dnsServers.add("127.0.0.1");
        }
    }

    // Create the extended resolver...
    final String[] serversArray = (String[]) dnsServers.toArray(new String[0]);

    if (logger.isInfoEnabled()) {
        for (int c = 0; c < serversArray.length; c++) {
            logger.info("DNS Server is: " + serversArray[c]);
        }
    }

    try {
        resolver = new ExtendedResolver(serversArray);
    } catch (UnknownHostException uhe) {
        logger.error("DNS service could not be initialized.  The DNS servers specified are not recognized hosts.", uhe);
        throw uhe;
    }

    cache = new Cache(DClass.IN);
    cache.setMaxEntries(maxCacheSize);

    if (setAsDNSJavaDefault) {
        Lookup.setDefaultResolver(resolver);
        Lookup.setDefaultCache(cache, DClass.IN);
        Lookup.setDefaultSearchPath(searchPaths);
        logger.info("Registered cache, resolver and search paths as DNSJava defaults");
    }

    // Cache the local hostname and local address. This is needed because
    // the following issues:
    // JAMES-787
    // JAMES-302
    InetAddress addr = getLocalHost();
    localCanonicalHostName = addr.getCanonicalHostName();
    localHostName = addr.getHostName();
    localAddress = addr.getHostAddress();

    logger.debug("DNSService ...init end");
}
 

import org.xbill.DNS.Cache; //导入依赖的package包/类
public void setCache(Cache c) {
    cache = c;
}