+/*
+ * 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.Filter;
+import org.apache.log4j.spi.ErrorHandler;
+import org.apache.log4j.spi.LoggingEvent;
+
+/**
+ Implement this interface for your own strategies for outputting log
+ statements.
+
+ @author Ceki Gülcü
+*/
+public interface Appender {
+
+ /**
+ Add a filter to the end of the filter list.
+
+ @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
+ */
+ public
+ Filter getFilter();
+
+ /**
+ Clear the list of filters by removing all the filters in it.
+
+ @since 0.9.0
+ */
+ public
+ void clearFilters();
+
+ /**
+ Release any resources allocated within the appender such as file
+ handles, network connections, etc.
+
+ <p>It is a programming error to append to a closed appender.
+
+ @since 0.8.4
+ */
+ public
+ void close();
+
+ /**
+ Log in <code>Appender</code> specific way. When appropriate,
+ Loggers will call the <code>doAppend</code> method of appender
+ implementations in order to log. */
+ public
+ void doAppend(LoggingEvent event);
+
+
+ /**
+ Get the name of this appender.
+ @return name, may be null.*/
+ public
+ String getName();
+
+
+ /**
+ Set the {@link ErrorHandler} for this appender.
+
+ @since 0.9.0
+ */
+ public
+ void setErrorHandler(ErrorHandler errorHandler);
+
+ /**
+ Returns the {@link ErrorHandler} for this appender.
+
+ @since 1.1
+ */
+ public
+ ErrorHandler getErrorHandler();
+
+ /**
+ Set the {@link Layout} for this appender.
+
+ @since 0.8.1
+ */
+ public
+ void setLayout(Layout layout);
+
+ /**
+ Returns this appenders layout.
+
+ @since 1.1
+ */
+ public
+ Layout getLayout();
+
+
+ /**
+ Set the name of this appender. The name is used by other
+ components to identify this appender.
+
+ @since 0.8.1
+ */
+ public
+ void setName(String name);
+
+ /**
+ Configurators call this method to determine if the appender
+ requires a layout. If this method returns <code>true</code>,
+ 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</code>, 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..
+
+ <p>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</code>.
+
+ @since 0.8.4 */
+ public
+ boolean requiresLayout();
+}