001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.logging.log4j.core.config.plugins;
018
019import java.lang.annotation.Documented;
020import java.lang.annotation.ElementType;
021import java.lang.annotation.Retention;
022import java.lang.annotation.RetentionPolicy;
023import java.lang.annotation.Target;
024
025import org.apache.logging.log4j.util.Strings;
026
027/**
028 * Annotation that identifies a Class as a Plugin.
029 */
030@Documented
031@Retention(RetentionPolicy.RUNTIME)
032@Target(ElementType.TYPE)
033public @interface Plugin {
034
035    /**
036     * Value of the elementType when none is specified.
037     */
038    String EMPTY = Strings.EMPTY;
039
040    /**
041     * Name of the plugin. Note that this name is case-insensitive.
042     */
043    String name();
044
045    /**
046     * Category to place the plugin under. Category names are case-sensitive.
047     */
048    String category();
049
050    /**
051     * Name of the corresponding category of elements this plugin belongs under. For example, {@code appender} would
052     * indicate an {@link org.apache.logging.log4j.core.Appender} plugin which would be in the
053     * {@code <Appenders/>} element of a {@link org.apache.logging.log4j.core.config.Configuration}.
054     */
055    String elementType() default EMPTY;
056
057    /**
058     * Indicates if the plugin class implements a useful {@link Object#toString()} method for use in log messages.
059     */
060    boolean printObject() default false;
061
062    boolean deferChildren() default false;
063}