1 /*
2 * Copyright 2001-2004 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 package org.apache.log4j;
18
19 import org.apache.log4j.spi.Filter;
20 import org.apache.log4j.spi.ErrorHandler;
21 import org.apache.log4j.spi.Layout;
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 Filter getFilter();
47
48 /**
49 * Clear the list of filters by removing all the filters in it.
50 *
51 * @since 0.9.0
52 */
53 public void clearFilters();
54
55 /**
56 * Release any resources allocated within the appender such as file
57 * handles, network connections, etc.
58 * <p/>
59 * <p>It is a programming error to append to a closed appender.
60 *
61 * @since 0.8.4
62 */
63 public void close();
64
65 /**
66 * Log in <code>Appender</code> specific way. When appropriate,
67 * Loggers will call the <code>doAppend</code> method of appender
68 * implementations in order to log.
69 */
70 public void doAppend(LoggingEvent event);
71
72 /**
73 * Get the name of this appender. The name uniquely identifies the
74 * appender.
75 */
76 public String getName();
77
78 /**
79 * Set the {@link ErrorHandler} for this appender.
80 *
81 * @since 0.9.0
82 */
83 public void setErrorHandler(ErrorHandler errorHandler);
84
85 /**
86 * Returns the {@link ErrorHandler} for this appender.
87 *
88 * @since 1.1
89 */
90 public ErrorHandler getErrorHandler();
91
92 /**
93 * Set the {@link Layout} for this appender.
94 *
95 * @since 0.8.1
96 */
97 public void setLayout(Layout layout);
98
99 /**
100 * Returns this appenders layout.
101 *
102 * @since 1.1
103 */
104 public Layout getLayout();
105
106 /**
107 * Set the name of this appender. The name is used by other
108 * components to identify this appender.
109 *
110 * @since 0.8.1
111 */
112 public void setName(String name);
113
114 /**
115 * Configurators call this method to determine if the appender
116 * requires a layout. If this method returns <code>true</code>,
117 * meaning that layout is required, then the configurator will
118 * configure an layout using the configuration information at its
119 * disposal. If this method returns <code>false</code>, meaning that
120 * a layout is not required, then layout configuration will be
121 * skipped even if there is available layout configuration
122 * information at the disposal of the configurator..
123 * <p/>
124 * <p>In the rather exceptional case, where the appender
125 * implementation admits a layout but can also work without it, then
126 * the appender should return <code>true</code>.
127 *
128 * @since 0.8.4
129 */
130 public boolean requiresLayout();
131 }