| /* |
| * 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.logging.log4j.core.lookup; |
| |
| import org.apache.logging.log4j.core.LogEvent; |
| import org.apache.logging.log4j.plugins.Plugin; |
| |
| /** |
| * Looks up keys from environment variables. |
| */ |
| @Plugin(name = "env", category = StrLookup.CATEGORY) |
| public class EnvironmentLookup extends AbstractLookup { |
| |
| /** |
| * Looks up the value of the given environment variable. |
| * |
| * @param event |
| * The current LogEvent (ignored by this StrLookup). |
| * @param key |
| * the key to look up, may be null |
| * @return the string value of the variable, or <code>null</code> if the variable is not defined in the system |
| * environment |
| */ |
| @Override |
| public String lookup(final LogEvent event, final String key) { |
| // getenv throws NullPointerException if <code>name</code> is <code>null</code> |
| return key != null ? System.getenv(key) : null; |
| } |
| } |