io.netty.resolver.HostsFileParser Maven / Gradle / Ivy
Go to download
This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright 2015 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:
*
* https://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 io.netty.resolver;
import java.io.File;
import java.io.IOException;
import java.io.Reader;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.nio.charset.Charset;
import java.util.List;
import java.util.HashMap;
import java.util.Map;
/**
* A parser for hosts files.
* The produced mappings contain only the first entry per hostname.
* Consider using {@link HostsFileEntriesProvider} when mappings with all entries per hostname are needed.
*/
public final class HostsFileParser {
/**
* Parse hosts file at standard OS location using the systems default {@link Charset} for decoding.
*
* @return a {@link HostsFileEntries}
*/
public static HostsFileEntries parseSilently() {
return hostsFileEntries(HostsFileEntriesProvider.parser().parseSilently());
}
/**
* Parse hosts file at standard OS location using the given {@link Charset}s one after each other until
* we were able to parse something or none is left.
*
* @param charsets the {@link Charset}s to try as file encodings when parsing.
* @return a {@link HostsFileEntries}
*/
public static HostsFileEntries parseSilently(Charset... charsets) {
return hostsFileEntries(HostsFileEntriesProvider.parser().parseSilently(charsets));
}
/**
* Parse hosts file at standard OS location using the system default {@link Charset} for decoding.
*
* @return a {@link HostsFileEntries}
* @throws IOException file could not be read
*/
public static HostsFileEntries parse() throws IOException {
return hostsFileEntries(HostsFileEntriesProvider.parser().parse());
}
/**
* Parse a hosts file using the system default {@link Charset} for decoding.
*
* @param file the file to be parsed
* @return a {@link HostsFileEntries}
* @throws IOException file could not be read
*/
public static HostsFileEntries parse(File file) throws IOException {
return hostsFileEntries(HostsFileEntriesProvider.parser().parse(file));
}
/**
* Parse a hosts file.
*
* @param file the file to be parsed
* @param charsets the {@link Charset}s to try as file encodings when parsing.
* @return a {@link HostsFileEntries}
* @throws IOException file could not be read
*/
public static HostsFileEntries parse(File file, Charset... charsets) throws IOException {
return hostsFileEntries(HostsFileEntriesProvider.parser().parse(file, charsets));
}
/**
* Parse a reader of hosts file format.
*
* @param reader the file to be parsed
* @return a {@link HostsFileEntries}
* @throws IOException file could not be read
*/
public static HostsFileEntries parse(Reader reader) throws IOException {
return hostsFileEntries(HostsFileEntriesProvider.parser().parse(reader));
}
/**
* Can't be instantiated.
*/
private HostsFileParser() {
}
@SuppressWarnings("unchecked")
private static HostsFileEntries hostsFileEntries(HostsFileEntriesProvider provider) {
return provider == HostsFileEntriesProvider.EMPTY ? HostsFileEntries.EMPTY :
new HostsFileEntries((Map) toMapWithSingleValue(provider.ipv4Entries()),
(Map) toMapWithSingleValue(provider.ipv6Entries()));
}
private static Map toMapWithSingleValue(Map> fromMapWithListValue) {
Map result = new HashMap(fromMapWithListValue.size());
for (Map.Entry> entry : fromMapWithListValue.entrySet()) {
List value = entry.getValue();
if (!value.isEmpty()) {
result.put(entry.getKey(), value.get(0));
}
}
return result;
}
}