/*
    * 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 java.util.Enumeration;
  
  import org.apache.log4j.helpers.NullEnumeration;
  import org.apache.log4j.legacy.core.ContextUtil;
  import org.apache.log4j.spi.HierarchyEventListener;
  import org.apache.log4j.spi.LoggerFactory;
  import org.apache.log4j.spi.LoggerRepository;
  import org.apache.log4j.spi.RepositorySelector;
  import org.apache.logging.log4j.spi.LoggerContext;
  import org.apache.logging.log4j.util.Strings;
  
  /**
   *
   */
  public final class LogManager {
  
      /**
       * @deprecated This variable is for internal use only. It will
       * become package protected in future versions.
       * */
      @Deprecated
      public static final String DEFAULT_CONFIGURATION_FILE = "log4j.properties";
  
      /**
       * @deprecated This variable is for internal use only. It will
       * become private in future versions.
       * */
      @Deprecated
      public static final String DEFAULT_CONFIGURATION_KEY = "log4j.configuration";
  
      /**
       * @deprecated This variable is for internal use only. It will
       * become private in future versions.
       * */
      @Deprecated
      public static final String CONFIGURATOR_CLASS_KEY = "log4j.configuratorClass";
  
      /**
       * @deprecated This variable is for internal use only. It will
       * become private in future versions.
       */
      @Deprecated
      public static final String DEFAULT_INIT_OVERRIDE_KEY = "log4j.defaultInitOverride";
  
      static final String DEFAULT_XML_CONFIGURATION_FILE = "log4j.xml";
  
      private static final LoggerRepository REPOSITORY = new Repository();
  
      private static final boolean isLog4jCore;
  
      static {
          boolean core = false;
          try {
              if (Class.forName("org.apache.logging.log4j.core.LoggerContext") != null) {
                  core = true;
              }
          } catch (Exception ex) {
              // Ignore the exception;
          }
          isLog4jCore = core;
      }
  
      private LogManager() {
      }
  
      public static Logger getRootLogger() {
          return Category.getInstance(PrivateManager.getContext(), Strings.EMPTY);
      }
  
      public static Logger getLogger(final String name) {
          return Category.getInstance(PrivateManager.getContext(), name);
      }
  
      public static Logger getLogger(final Class<?> clazz) {
          return Category.getInstance(PrivateManager.getContext(), clazz.getName());
      }
  
      public static Logger getLogger(final String name, final LoggerFactory factory) {
          return Category.getInstance(PrivateManager.getContext(), name);
      }
  
     public static Logger exists(final String name) {
         final LoggerContext ctx = PrivateManager.getContext();
         if (!ctx.hasLogger(name)) {
             return null;
         }
         return Logger.getLogger(name);
     }
 
     @SuppressWarnings("rawtypes")
     public static Enumeration getCurrentLoggers() {
         return NullEnumeration.getInstance();
     }
 
     static void reconfigure() {
         if (isLog4jCore) {
             final LoggerContext ctx = PrivateManager.getContext();
             ContextUtil.reconfigure(ctx);
         }
     }
 
     /**
      * No-op implementation.
      */
     public static void shutdown() {
     }
 
     /**
      * No-op implementation.
      */
     public static void resetConfiguration() {
     }
 
     /**
      * No-op implementation.
      * @param selector The RepositorySelector.
      * @param guard prevents calls at the incorrect time.
      * @throws IllegalArgumentException if a parameter is invalid.
      */
     public static void setRepositorySelector(final RepositorySelector selector, final Object guard)
         throws IllegalArgumentException {
     }
 
     public static LoggerRepository getLoggerRepository() {
         return REPOSITORY;
     }
 
     /**
      * The Repository.
      */
     private static class Repository implements LoggerRepository {
         @Override
         public void addHierarchyEventListener(final HierarchyEventListener listener) {
 
         }
 
         @Override
         public boolean isDisabled(final int level) {
             return false;
         }
 
         @Override
         public void setThreshold(final Level level) {
 
         }
 
         @Override
         public void setThreshold(final String val) {
 
         }
 
         @Override
         public void emitNoAppenderWarning(final Category cat) {
 
         }
 
         @Override
         public Level getThreshold() {
             return Level.OFF;
         }
 
         @Override
         public Logger getLogger(final String name) {
             return Category.getInstance(PrivateManager.getContext(), name);
         }
 
         @Override
         public Logger getLogger(final String name, final LoggerFactory factory) {
             return Category.getInstance(PrivateManager.getContext(), name);
         }
 
         @Override
         public Logger getRootLogger() {
             return Category.getRoot(PrivateManager.getContext());
         }
 
         @Override
         public Logger exists(final String name) {
             return LogManager.exists(name);
         }
 
         @Override
         public void shutdown() {
         }
 
         @Override
         @SuppressWarnings("rawtypes")
         public Enumeration getCurrentLoggers() {
             return NullEnumeration.getInstance();
         }
 
         @Override
         @SuppressWarnings("rawtypes")
         public Enumeration getCurrentCategories() {
             return NullEnumeration.getInstance();
         }
 
         @Override
         public void fireAddAppenderEvent(final Category logger, final Appender appender) {
         }
 
         @Override
         public void resetConfiguration() {
         }
     }
 
     /**
      * Internal LogManager.
      */
     private static class PrivateManager extends org.apache.logging.log4j.LogManager {
         private static final String FQCN = LogManager.class.getName();
 
         public static LoggerContext getContext() {
             return getContext(FQCN, false);
         }
 
         public static org.apache.logging.log4j.Logger getLogger(final String name) {
             return getLogger(FQCN, name);
         }
     }
 }