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