org.glowroot.shaded.netty.util.DomainNameMapping Maven / Gradle / Ivy
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/*
* Copyright 2014 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
package org.glowroot.shaded.netty.util;
import org.glowroot.shaded.netty.util.internal.StringUtil;
import java.net.IDN;
import java.util.LinkedHashMap;
import java.util.Locale;
import java.util.Map;
import java.util.regex.Pattern;
/**
* Maps a domain name to its associated value object.
*
* DNS wildcard is supported as hostname, so you can use {@code *.netty.io} to match both {@code netty.io}
* and {@code downloads.netty.io}.
*
*/
public class DomainNameMapping implements Mapping {
private static final Pattern DNS_WILDCARD_PATTERN = Pattern.compile("^\\*\\..*");
private final Map map;
private final V defaultValue;
/**
* Creates a default, order-sensitive mapping. If your hostnames are in conflict, the mapping
* will choose the one you add first.
*
* @param defaultValue the default value for {@link #map(String)} to return when nothing matches the input
*/
public DomainNameMapping(V defaultValue) {
this(4, defaultValue);
}
/**
* Creates a default, order-sensitive mapping. If your hostnames are in conflict, the mapping
* will choose the one you add first.
*
* @param initialCapacity initial capacity for the internal map
* @param defaultValue the default value for {@link #map(String)} to return when nothing matches the input
*/
public DomainNameMapping(int initialCapacity, V defaultValue) {
if (defaultValue == null) {
throw new NullPointerException("defaultValue");
}
map = new LinkedHashMap(initialCapacity);
this.defaultValue = defaultValue;
}
/**
* Adds a mapping that maps the specified (optionally wildcard) host name to the specified output value.
*
* DNS wildcard is supported as hostname.
* For example, you can use {@code *.netty.io} to match {@code netty.io} and {@code downloads.netty.io}.
*
*
* @param hostname the host name (optionally wildcard)
* @param output the output value that will be returned by {@link #map(String)} when the specified host name
* matches the specified input host name
*/
public DomainNameMapping add(String hostname, V output) {
if (hostname == null) {
throw new NullPointerException("input");
}
if (output == null) {
throw new NullPointerException("output");
}
map.put(normalizeHostname(hostname), output);
return this;
}
/**
* Simple function to match DNS wildcard.
*/
private static boolean matches(String hostNameTemplate, String hostName) {
// note that inputs are converted and lowercased already
if (DNS_WILDCARD_PATTERN.matcher(hostNameTemplate).matches()) {
return hostNameTemplate.substring(2).equals(hostName) ||
hostName.endsWith(hostNameTemplate.substring(1));
} else {
return hostNameTemplate.equals(hostName);
}
}
/**
* IDNA ASCII conversion and case normalization
*/
private static String normalizeHostname(String hostname) {
if (needsNormalization(hostname)) {
hostname = IDN.toASCII(hostname, IDN.ALLOW_UNASSIGNED);
}
return hostname.toLowerCase(Locale.US);
}
private static boolean needsNormalization(String hostname) {
final int length = hostname.length();
for (int i = 0; i < length; i ++) {
int c = hostname.charAt(i);
if (c > 0x7F) {
return true;
}
}
return false;
}
@Override
public V map(String input) {
if (input != null) {
input = normalizeHostname(input);
for (Map.Entry entry : map.entrySet()) {
if (matches(entry.getKey(), input)) {
return entry.getValue();
}
}
}
return defaultValue;
}
@Override
public String toString() {
return StringUtil.simpleClassName(this) + "(default: " + defaultValue + ", map: " + map + ')';
}
}