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. 78 @return name, may be null.*/ 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 }