001/* 002 * Copyright 2015-2020 the original author or authors 003 * 004 * This software is licensed under the Apache License, Version 2.0, 005 * the GNU Lesser General Public License version 2 or later ("LGPL") 006 * and the WTFPL. 007 * You may choose either license to govern your use of this software only 008 * upon the condition that you accept all of the terms of either 009 * the Apache License 2.0, the LGPL 2.1+ or the WTFPL. 010 */ 011package org.minidns; 012 013import org.minidns.dnsmessage.DnsMessage; 014import org.minidns.dnsname.DnsName; 015import org.minidns.dnsqueryresult.CachedDnsQueryResult; 016import org.minidns.dnsqueryresult.DnsQueryResult; 017 018/** 019 * Cache for DNS Entries. Implementations must be thread safe. 020 */ 021public abstract class DnsCache { 022 023 public static final int DEFAULT_CACHE_SIZE = 512; 024 025 /** 026 * Add an an dns answer/response for a given dns question. Implementations 027 * should honor the ttl / receive timestamp. 028 * @param query The query message containing a question. 029 * @param result The DNS query result. 030 */ 031 public final void put(DnsMessage query, DnsQueryResult result) { 032 putNormalized(query.asNormalizedVersion(), result); 033 } 034 035 protected abstract void putNormalized(DnsMessage normalizedQuery, DnsQueryResult result); 036 037 public abstract void offer(DnsMessage query, DnsQueryResult result, DnsName authoritativeZone); 038 039 /** 040 * Request a cached dns response. 041 * @param query The query message containing a question. 042 * @return The dns message. 043 */ 044 public final CachedDnsQueryResult get(DnsMessage query) { 045 return getNormalized(query.asNormalizedVersion()); 046 } 047 048 protected abstract CachedDnsQueryResult getNormalized(DnsMessage normalizedQuery); 049 050}