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 */ addFilter(Filter newFilter)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 */ getFilter()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 */ clearFilters()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 */ close()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 */ doAppend(LoggingEvent event)70 public void doAppend(LoggingEvent event); 71 72 /** 73 * Get the name of this appender. The name uniquely identifies the 74 * appender. 75 */ getName()76 public String getName(); 77 78 /** 79 * Set the {@link ErrorHandler} for this appender. 80 * 81 * @since 0.9.0 82 */ setErrorHandler(ErrorHandler errorHandler)83 public void setErrorHandler(ErrorHandler errorHandler); 84 85 /** 86 * Returns the {@link ErrorHandler} for this appender. 87 * 88 * @since 1.1 89 */ getErrorHandler()90 public ErrorHandler getErrorHandler(); 91 92 /** 93 * Set the {@link Layout} for this appender. 94 * 95 * @since 0.8.1 96 */ setLayout(Layout layout)97 public void setLayout(Layout layout); 98 99 /** 100 * Returns this appenders layout. 101 * 102 * @since 1.1 103 */ getLayout()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 */ setName(String name)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 */ requiresLayout()130 public boolean requiresLayout(); 131 } 132