org.apache.log4j.Appender Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.log4j;
import org.apache.log4j.spi.ErrorHandler;
import org.apache.log4j.spi.Filter;
import org.apache.log4j.spi.LoggingEvent;
/**
* Implement this interface for your own strategies for outputting log
* statements.
*/
public interface Appender {
/**
* Add a filter to the end of the filter list.
* @param newFilter The filter to add.
*
* @since 0.9.0
*/
void addFilter(Filter newFilter);
/**
* Returns the head Filter. The Filters are organized in a linked list
* and so all Filters on this Appender are available through the result.
*
* @return the head Filter or null, if no Filters are present
* @since 1.1
*/
Filter getFilter();
/**
* Clear the list of filters by removing all the filters in it.
*
* @since 0.9.0
*/
void clearFilters();
/**
* Release any resources allocated within the appender such as file
* handles, network connections, etc.
*
* It is a programming error to append to a closed appender.
*
*
* @since 0.8.4
*/
void close();
/**
* Log in Appender specific way. When appropriate,
* Loggers will call the doAppend method of appender
* implementations in order to log.
* @param event The LoggingEvent.
*/
void doAppend(LoggingEvent event);
/**
* Get the name of this appender.
*
* @return name, may be null.
*/
String getName();
/**
* Set the {@link ErrorHandler} for this appender.
* @param errorHandler The error handler.
*
* @since 0.9.0
*/
void setErrorHandler(ErrorHandler errorHandler);
/**
* Returns the {@link ErrorHandler} for this appender.
* @return The error handler.
*
* @since 1.1
*/
ErrorHandler getErrorHandler();
/**
* Set the {@link Layout} for this appender.
* @param layout The Layout.
*
* @since 0.8.1
*/
void setLayout(Layout layout);
/**
* Returns this appenders layout.
* @return the Layout.
*
* @since 1.1
*/
Layout getLayout();
/**
* Set the name of this appender. The name is used by other
* components to identify this appender.
* @param name The appender name.
*
* @since 0.8.1
*/
void setName(String name);
/**
* Configurators call this method to determine if the appender
* requires a layout. If this method returns {@code true},
* meaning that layout is required, then the configurator will
* configure an layout using the configuration information at its
* disposal. If this method returns {@code false}, meaning that
* a layout is not required, then layout configuration will be
* skipped even if there is available layout configuration
* information at the disposal of the configurator..
*
* In the rather exceptional case, where the appender
* implementation admits a layout but can also work without it, then
* the appender should return {@code true}.
*
* @return true if a Layout is required.
*
* @since 0.8.4
*/
boolean requiresLayout();
}