com.groupbyinc.common.apache.commons.text.lookup.LocalHostStringLookup Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.commons.text.lookup;
import java.net.InetAddress;
import java.net.UnknownHostException;
/**
* Looks up keys related to the local host: host name, canonical host name, host address.
*
* The lookup keys are:
*
*
* - name: for the local host name, for example {@code EXAMPLE}.
* - canonical-name: for the local canonical host name, for example {@code EXAMPLE.apache.org}.
* - address: for the local host address, for example {@code 192.168.56.1}.
*
*
* @since 1.3
*/
final class LocalHostStringLookup extends AbstractStringLookup {
/**
* Defines the singleton for this class.
*/
static final LocalHostStringLookup INSTANCE = new LocalHostStringLookup();
/**
* No need to build instances for now.
*/
private LocalHostStringLookup() {
// empty
}
/**
* Looks up the value of the Java platform key.
*
* @param key
* the key to be looked up, may be null
* @return The value of the environment variable.
*/
@Override
public String lookup(final String key) {
switch (key) {
case "name":
try {
return InetAddress.getLocalHost().getHostName();
} catch (final UnknownHostException e) {
return null;
}
case "canonical-name":
try {
return InetAddress.getLocalHost().getCanonicalHostName();
} catch (final UnknownHostException e) {
return null;
}
case "address":
try {
return InetAddress.getLocalHost().getHostAddress();
} catch (final UnknownHostException e) {
return null;
}
default:
throw new IllegalArgumentException(key);
}
}
}