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 */ 017package org.apache.logging.log4j.core.lookup; 018 019import org.apache.logging.log4j.Logger; 020import org.apache.logging.log4j.Marker; 021import org.apache.logging.log4j.MarkerManager; 022import org.apache.logging.log4j.core.LogEvent; 023import org.apache.logging.log4j.core.config.plugins.Plugin; 024import org.apache.logging.log4j.status.StatusLogger; 025 026/** 027 * Looks up keys from system properties. 028 */ 029@Plugin(name = "sys", category = StrLookup.CATEGORY) 030public class SystemPropertiesLookup extends AbstractLookup { 031 032 private static final Logger LOGGER = StatusLogger.getLogger(); 033 private static final Marker LOOKUP = MarkerManager.getMarker("LOOKUP"); 034 035 /** 036 * Looks up the value for the key using the data in the LogEvent. 037 * @param event The current LogEvent. 038 * @param key the key to be looked up, may be null 039 * @return The value associated with the key. 040 */ 041 @Override 042 public String lookup(final LogEvent event, final String key) { 043 try { 044 return System.getProperty(key); 045 } catch (final Exception ex) { 046 LOGGER.warn(LOOKUP, "Error while getting system property [{}].", key, ex); 047 return null; 048 } 049 } 050}