1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache license, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the license for the specific language governing permissions and 15 * limitations under the license. 16 */ 17 package org.apache.logging.log4j.core.lookup; 18 19 import org.apache.logging.log4j.Logger; 20 import org.apache.logging.log4j.Marker; 21 import org.apache.logging.log4j.MarkerManager; 22 import org.apache.logging.log4j.core.LogEvent; 23 import org.apache.logging.log4j.core.config.plugins.Plugin; 24 import org.apache.logging.log4j.status.StatusLogger; 25 26 /** 27 * Looks up keys from system properties. 28 */ 29 @Plugin(name = "sys", category = StrLookup.CATEGORY) 30 public class SystemPropertiesLookup extends AbstractLookup { 31 32 private static final Logger LOGGER = StatusLogger.getLogger(); 33 private static final Marker LOOKUP = MarkerManager.getMarker("LOOKUP"); 34 35 /** 36 * Looks up the value for the key using the data in the LogEvent. 37 * @param event The current LogEvent. 38 * @param key the key to be looked up, may be null 39 * @return The value associated with the key. 40 */ 41 @Override 42 public String lookup(final LogEvent event, final String key) { 43 try { 44 return System.getProperty(key); 45 } catch (final Exception ex) { 46 LOGGER.warn(LOOKUP, "Error while getting system property [{}].", key, ex); 47 return null; 48 } 49 } 50 }