| /* |
| * 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. |
| * <p> |
| * The lookup keys are: |
| * </p> |
| * <ul> |
| * <li><b>name</b>: for the local host name, for example {@code EXAMPLE}.</li> |
| * <li><b>canonical-name</b>: for the local canonical host name, for example {@code EXAMPLE.apache.org}.</li> |
| * <li><b>address</b>: for the local host address, for example {@code 192.168.56.1}.</li> |
| * </ul> |
| * |
| * @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 a local host 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) { |
| if (key == null) { |
| return null; |
| } |
| try { |
| switch (key) { |
| case InetAddressKeys.KEY_NAME: |
| return InetAddress.getLocalHost().getHostName(); |
| case InetAddressKeys.KEY_CANONICAL_NAME: |
| return InetAddress.getLocalHost().getCanonicalHostName(); |
| case InetAddressKeys.KEY_ADDRESS: |
| return InetAddress.getLocalHost().getHostAddress(); |
| default: |
| throw new IllegalArgumentException(key); |
| } |
| } catch (UnknownHostException e) { |
| return null; |
| } |
| } |
| } |