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 18 package org.apache.log4j; 19 20 import org.apache.log4j.util.Filter; 21 22 /** 23 * This class switches MDC values into the order 24 * (unreasonably) expected by the witness files. 25 */ 26 public class MDCOrderFilter implements Filter { 27 28 /** 29 * Unexpected orders of keys. 30 * Note expected values are "va-one-one" and "va-one-two". 31 */ 32 private static final String[] patterns = 33 new String[] { 34 "{key2,va12}{key1,va11}", 35 "{key2,value2}{key1,value1}" 36 }; 37 38 /** 39 * Replacement values. 40 */ 41 private static final String[] replacements = 42 new String[] { 43 "{key1,va11}{key2,va12}", 44 "{key1,value1}{key2,value2}" 45 }; 46 47 /** 48 * Switch order of MDC keys when not in expected order. 49 */ 50 public String filter(final String in) { 51 if (in == null) { 52 return null; 53 } 54 55 for(int i = 0; i < patterns.length; i++) { 56 int ipos = in.indexOf(patterns[i]); 57 if (ipos >= 1) { 58 return in.substring(0, ipos) 59 + replacements[i] 60 + in.substring(ipos + patterns[i].length()); 61 } 62 } 63 return in; 64 } 65 }