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 }