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    1   /*
    2    * Licensed to the Apache Software Foundation (ASF) under one or more
    3    * contributor license agreements. See the NOTICE file distributed with
    4    * this work for additional information regarding copyright ownership.
    5    * The ASF licenses this file to You under the Apache license, Version 2.0
    6    * (the "License"); you may not use this file except in compliance with
    7    * the License. You may obtain a copy of the License at
    8    *
    9    *      http://www.apache.org/licenses/LICENSE-2.0
    10   *
    11   * Unless required by applicable law or agreed to in writing, software
    12   * distributed under the License is distributed on an "AS IS" BASIS,
    13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    14   * See the license for the specific language governing permissions and
    15   * limitations under the license.
    16   */
    17  package org.apache.logging.log4j.web;
    18
    19  import org.apache.logging.log4j.spi.LoggerContext;
    20
    21  /**
    22   * Specifies an interface for setting and clearing a thread-bound {@link LoggerContext} in a Java EE web application.
    23   * Also defines constants for context parameter and attribute names. In most cases you will never need to use this
    24   * directly because the Log4j filter handles this task automatically. However, in async operations you should wrap
    25   * code that executes in separate threads with {@link #setLoggerContext} and {@link #clearLoggerContext}.
    26   *
    27   * <p>
    28   * You can obtain the instance of this for your web application by retrieving the {@link javax.servlet.ServletContext}
    29   * attribute named {@code org.apache.logging.log4j.core.web.Log4jWebSupport.INSTANCE}. If needed, you can also obtain
    30   * the {@link LoggerContext} instance for your web application by retrieving the {@code ServletContext} attribute named
    31   * {@code org.apache.logging.log4j.spi.LoggerContext.INSTANCE}.
    32   * </p>
    33   */
    34  public interface Log4jWebSupport {
    35      /**
    36       * The {@link javax.servlet.ServletContext} parameter name for the name of the
    37       * {@link org.apache.logging.log4j.core.LoggerContext}.
    38       */
    39      String LOG4J_CONTEXT_NAME = "log4jContextName";
    40
    41      /**
    42       * The {@link javax.servlet.ServletContext} parameter name for the location of the configuration.
    43       */
    44      String LOG4J_CONFIG_LOCATION = "log4jConfiguration";
    45
    46      /**
    47       * The {@link javax.servlet.ServletContext} parameter name for the JNDI flag.
    48       */
    49      String IS_LOG4J_CONTEXT_SELECTOR_NAMED = "isLog4jContextSelectorNamed";
    50
    51      /**
    52       * The {@link javax.servlet.ServletContext} parameter name for the flag that disables Log4j's auto-initialization
    53       * in Servlet 3.0+ web applications. Set a context parameter with this name to "true" to disable
    54       * auto-initialization.
    55       */
    56      String IS_LOG4J_AUTO_INITIALIZATION_DISABLED = "isLog4jAutoInitializationDisabled";
    57
    58      /**
    59       * The attribute key for the {@link javax.servlet.ServletContext} attribute that the singleton support instance
    60       * is stored in.
    61       */
    62      String SUPPORT_ATTRIBUTE = Log4jWebSupport.class.getName() + ".INSTANCE";
    63
    64      /**
    65       * The attribute key for the {@link javax.servlet.ServletContext} attribute that the {@link LoggerContext}
    66       * is stored in.
    67       */
    68      String CONTEXT_ATTRIBUTE = LoggerContext.class.getName() + ".INSTANCE";
    69
    70      /**
    71       * Sets the logger context so that code executing afterwards can easily and quickly access loggers via
    72       * {@link org.apache.logging.log4j.LogManager#getLogger}.
    73       */
    74      void setLoggerContext();
    75
    76      /**
    77       * Clears the logger context set up in {@link #setLoggerContext}.
    78       */
    79      void clearLoggerContext();
    80
    81      /**
    82       * Sets the logger context by calling {@link #setLoggerContext}, executes the runnable argument, then clears the
    83       * logger context by calling {@link #clearLoggerContext}.
    84       *
    85       * @param runnable The runnable to execute wrapped with a configured logger context
    86       */
    87      void wrapExecution(Runnable runnable);
    88  }