Apache Log4j Core Implementation provides the functional components of the logging system. Users are free to create their own plugins and include them in the logging configuration. Apache Log4j Core is a required module to use Apache Log4j.

Bytecode (Java 8) for Apache Log4j Core Implementation is provided in a separate JAR file like log4j-core-2.14.1.jar.

Source Code files for Apache Log4j API are provided in both binary packge like apache-log4j-2.14.1-bin.zip and source package like apache-log4j-2.14.1-src.zip. You can download them at Apache Log4j Website.

You can also browse Source Code files for Apache Log4j Core Implementation 2.14.1 below.

⏎ org/apache/logging/log4j/core/config/plugins/PluginAttribute.java

/*
 * 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.logging.log4j.core.config.plugins;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.apache.logging.log4j.core.config.plugins.visitors.PluginAttributeVisitor;
import org.apache.logging.log4j.util.Strings;

/**
 * Identifies a Plugin Attribute and its default value. Note that only one of the defaultFoo attributes will be
 * used based on the type this annotation is attached to. Thus, for primitive types, the default<i>Type</i>
 * attribute will be used for some <i>Type</i>. However, for more complex types (including enums), the default
 * string value is used instead and should correspond to the string that would correctly convert to the appropriate
 * enum value using {@link Enum#valueOf(Class, String) Enum.valueOf}.
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.PARAMETER, ElementType.FIELD})
@PluginVisitorStrategy(PluginAttributeVisitor.class)
public @interface PluginAttribute {

    /**
     * Specifies the default boolean value to use.
     */
    boolean defaultBoolean() default false;

    /**
     * Specifies the default byte value to use.
     */
    byte defaultByte() default 0;

    /**
     * Specifies the default byte value to use.
     */
    char defaultChar() default 0;

    /**
     * Specifies the default {@link Class} value to use.
     */
    Class<?> defaultClass() default Object.class;

    /**
     * Specifies the default double floating point value to use.
     */
    double defaultDouble() default 0.0d;

    /**
     * Specifies the default floating point value to use.
     */
    float defaultFloat() default 0.0f;

    /**
     * Specifies the default integer value to use.
     */
    int defaultInt() default 0;

    /**
     * Specifies the default long value to use.
     */
    long defaultLong() default 0L;

    /**
     * Specifies the default long value to use.
     */
    short defaultShort() default 0;

    /**
     * Specifies the default value this attribute should use if none is provided or if the provided value is invalid.
     */
    String defaultString() default Strings.EMPTY;

    // TODO: could we allow a blank value and infer the attribute name through reflection?
    /**
     * Specifies the name of the attribute (case-insensitive) this annotation corresponds to.
     */
    String value();

    /**
     * Indicates that this attribute is a sensitive one that shouldn't be logged directly. Such attributes will instead
     * be output as a hashed value.
     */
    boolean sensitive() default false;

}

⏎ org/apache/logging/log4j/core/config/plugins/PluginAttribute.java

Or download all of them as a single archive file:

File name: log4j-core-2.14.1-sources.jar
File size: 1281358 bytes
Release date: 2021-03-06
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