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.Filter;
21 import org.apache.log4j.spi.ErrorHandler;
22 import org.apache.log4j.spi.LoggingEvent;
23
24 /**
25 Implement this interface for your own strategies for outputting log
26 statements.
27
28 @author Ceki Gülcü
29 */
30 public interface Appender {
31
32 /**
33 Add a filter to the end of the filter list.
34
35 @since 0.9.0
36 */
37 void addFilter(Filter newFilter);
38
39 /**
40 Returns the head Filter. The Filters are organized in a linked list
41 and so all Filters on this Appender are available through the result.
42
43 @return the head Filter or null, if no Filters are present
44 @since 1.1
45 */
46 public
47 Filter getFilter();
48
49 /**
50 Clear the list of filters by removing all the filters in it.
51
52 @since 0.9.0
53 */
54 public
55 void clearFilters();
56
57 /**
58 Release any resources allocated within the appender such as file
59 handles, network connections, etc.
60
61 <p>It is a programming error to append to a closed appender.
62
63 @since 0.8.4
64 */
65 public
66 void close();
67
68 /**
69 Log in <code>Appender</code> specific way. When appropriate,
70 Loggers will call the <code>doAppend</code> method of appender
71 implementations in order to log. */
72 public
73 void doAppend(LoggingEvent event);
74
75
76 /**
77 Get the name of this appender. The name uniquely identifies the
78 appender. */
79 public
80 String getName();
81
82
83 /**
84 Set the {@link ErrorHandler} for this appender.
85
86 @since 0.9.0
87 */
88 public
89 void setErrorHandler(ErrorHandler errorHandler);
90
91 /**
92 Returns the {@link ErrorHandler} for this appender.
93
94 @since 1.1
95 */
96 public
97 ErrorHandler getErrorHandler();
98
99 /**
100 Set the {@link Layout} for this appender.
101
102 @since 0.8.1
103 */
104 public
105 void setLayout(Layout layout);
106
107 /**
108 Returns this appenders layout.
109
110 @since 1.1
111 */
112 public
113 Layout getLayout();
114
115
116 /**
117 Set the name of this appender. The name is used by other
118 components to identify this appender.
119
120 @since 0.8.1
121 */
122 public
123 void setName(String name);
124
125 /**
126 Configurators call this method to determine if the appender
127 requires a layout. If this method returns <code>true</code>,
128 meaning that layout is required, then the configurator will
129 configure an layout using the configuration information at its
130 disposal. If this method returns <code>false</code>, meaning that
131 a layout is not required, then layout configuration will be
132 skipped even if there is available layout configuration
133 information at the disposal of the configurator..
134
135 <p>In the rather exceptional case, where the appender
136 implementation admits a layout but can also work without it, then
137 the appender should return <code>true</code>.
138
139 @since 0.8.4 */
140 public
141 boolean requiresLayout();
142 }
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