e8efcd82a8
Motivation: We can just use Objects.requireNonNull(...) as a replacement for ObjectUtil.checkNotNull(....) Modifications: - Use Objects.requireNonNull(...) Result: Less code to maintain.
102 lines
3.2 KiB
Java
102 lines
3.2 KiB
Java
/*
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* Copyright 2018 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.util.AsciiString;
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import io.netty.util.internal.UnstableApi;
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import java.util.List;
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import static io.netty.util.internal.ObjectUtil.checkPositive;
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import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
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import static java.util.Objects.requireNonNull;
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/**
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* Default implementation of a {@link DnsCnameCache}.
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*/
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@UnstableApi
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public final class DefaultDnsCnameCache implements DnsCnameCache {
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private final int minTtl;
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private final int maxTtl;
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private final Cache<String> cache = new Cache<String>() {
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@Override
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protected boolean shouldReplaceAll(String entry) {
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// Only one 1:1 mapping is supported as specified in the RFC.
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return true;
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}
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@Override
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protected boolean equals(String entry, String otherEntry) {
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return AsciiString.contentEqualsIgnoreCase(entry, otherEntry);
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}
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};
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/**
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* Create a cache that respects the TTL returned by the DNS server.
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*/
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public DefaultDnsCnameCache() {
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this(0, Cache.MAX_SUPPORTED_TTL_SECS);
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}
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/**
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* Create a cache.
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*
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* @param minTtl the minimum TTL
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* @param maxTtl the maximum TTL
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*/
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public DefaultDnsCnameCache(int minTtl, int maxTtl) {
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this.minTtl = Math.min(Cache.MAX_SUPPORTED_TTL_SECS, checkPositiveOrZero(minTtl, "minTtl"));
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this.maxTtl = Math.min(Cache.MAX_SUPPORTED_TTL_SECS, checkPositive(maxTtl, "maxTtl"));
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if (minTtl > maxTtl) {
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throw new IllegalArgumentException(
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"minTtl: " + minTtl + ", maxTtl: " + maxTtl + " (expected: 0 <= minTtl <= maxTtl)");
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}
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}
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@SuppressWarnings("unchecked")
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@Override
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public String get(String hostname) {
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requireNonNull(hostname, "hostname");
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List<? extends String> cached = cache.get(hostname);
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if (cached == null || cached.isEmpty()) {
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return null;
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}
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// We can never have more then one record.
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return cached.get(0);
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}
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@Override
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public void cache(String hostname, String cname, long originalTtl, EventLoop loop) {
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requireNonNull(hostname, "hostname");
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requireNonNull(cname, "cname");
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requireNonNull(loop, "loop");
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cache.cache(hostname, cname, Math.max(minTtl, (int) Math.min(maxTtl, originalTtl)), loop);
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}
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@Override
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public void clear() {
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cache.clear();
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}
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@Override
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public boolean clear(String hostname) {
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requireNonNull(hostname, "hostname");
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return cache.clear(hostname);
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}
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}
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