001 /* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache license, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the license for the specific language governing permissions and 015 * limitations under the license. 016 */ 017 package org.apache.logging.log4j.core.lookup; 018 019 import org.apache.logging.log4j.core.LogEvent; 020 import org.apache.logging.log4j.core.config.plugins.Plugin; 021 022 /** 023 * Looks up keys from system properties. 024 */ 025 @Plugin(name = "sys", type = "Lookup") 026 public class SystemPropertiesLookup implements StrLookup { 027 028 /** 029 * Lookup the value for the key. 030 * @param key the key to be looked up, may be null 031 * @return The value for the key. 032 */ 033 public String lookup(final String key) { 034 try { 035 return System.getProperty(key); 036 } catch (Exception ex) { 037 return null; 038 } 039 } 040 041 /** 042 * Lookup the value for the key using the data in the LogEvent. 043 * @param event The current LogEvent. 044 * @param key the key to be looked up, may be null 045 * @return The value associated with the key. 046 */ 047 public String lookup(final LogEvent event, final String key) { 048 try { 049 return System.getProperty(key); 050 } catch (Exception ex) { 051 return null; 052 } 053 } 054 }