566566db3a
Motivation: DnsCache (an interface) is coupled to DnsCacheEntry (a final class). This means that DnsCache implementations can't implement their own DnsCacheEntry objects if the default behavior isn't appropriate. Modifications: - DnsCacheEntry should be moved to DefaultDnsCache as it is an implementation detail - DnsCache#cache(..) should return a new DnsCacheEntry - The methods which from DnsCacheEntry that were used outside the scope of DefaultDnsCache should be moved into an interface Result: DnsCache is more extensible and not tightly coupled to a default implementation of DnsCacheEntry.
93 lines
2.4 KiB
Java
93 lines
2.4 KiB
Java
/*
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* Copyright 2016 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.resolver.dns;
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import io.netty.channel.EventLoop;
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import io.netty.handler.codec.dns.DnsRecord;
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import io.netty.util.internal.UnstableApi;
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import java.net.InetAddress;
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import java.util.Collections;
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import java.util.List;
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/**
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* A noop DNS cache that actually never caches anything.
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*/
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@UnstableApi
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public final class NoopDnsCache implements DnsCache {
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public static final NoopDnsCache INSTANCE = new NoopDnsCache();
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/**
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* Private singleton constructor.
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*/
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private NoopDnsCache() {
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}
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@Override
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public void clear() {
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}
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@Override
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public boolean clear(String hostname) {
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return false;
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}
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@Override
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public List<? extends DnsCacheEntry> get(String hostname, DnsRecord[] additionals) {
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return Collections.emptyList();
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}
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@Override
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public DnsCacheEntry cache(String hostname, DnsRecord[] additional,
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InetAddress address, long originalTtl, EventLoop loop) {
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return new NoopDnsCacheEntry(address);
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}
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@Override
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public DnsCacheEntry cache(String hostname, DnsRecord[] additional, Throwable cause, EventLoop loop) {
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return null;
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}
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@Override
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public String toString() {
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return NoopDnsCache.class.getSimpleName();
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}
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private static final class NoopDnsCacheEntry implements DnsCacheEntry {
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private final InetAddress address;
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NoopDnsCacheEntry(InetAddress address) {
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this.address = address;
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}
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@Override
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public InetAddress address() {
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return address;
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}
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@Override
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public Throwable cause() {
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return null;
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}
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@Override
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public String toString() {
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return address.toString();
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}
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}
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}
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