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.spi.OptionHandler;
21 import org.apache.log4j.spi.LoggingEvent;
22
23 /**
24 Extend this abstract class to create your own log layout format.
25
26 @author Ceki Gülcü
27
28 */
29
30 public abstract class Layout implements OptionHandler {
31
32 // Note that the line.separator property can be looked up even by
33 // applets.
34 public final static String LINE_SEP = System.getProperty("line.separator");
35 public final static int LINE_SEP_LEN = LINE_SEP.length();
36
37
38 /**
39 Implement this method to create your own layout format.
40 */
41 abstract
42 public
43 String format(LoggingEvent event);
44
45 /**
46 Returns the content type output by this layout. The base class
47 returns "text/plain".
48 */
49 public
50 String getContentType() {
51 return "text/plain";
52 }
53
54 /**
55 Returns the header for the layout format. The base class returns
56 <code>null</code>. */
57 public
58 String getHeader() {
59 return null;
60 }
61
62 /**
63 Returns the footer for the layout format. The base class returns
64 <code>null</code>. */
65 public
66 String getFooter() {
67 return null;
68 }
69
70
71
72 /**
73 If the layout handles the throwable object contained within
74 {@link LoggingEvent}, then the layout should return
75 <code>false</code>. Otherwise, if the layout ignores throwable
76 object, then the layout should return <code>true</code>.
77
78 <p>The {@link SimpleLayout}, {@link TTCCLayout}, {@link
79 PatternLayout} all return <code>true</code>. The {@link
80 org.apache.log4j.xml.XMLLayout} returns <code>false</code>.
81
82 @since 0.8.4 */
83 abstract
84 public
85 boolean ignoresThrowable();
86
87 }
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