content: /*
   * 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.bookkeeper.slogger.slf4j;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import java.util.Optional;
  import org.apache.bookkeeper.slogger.AbstractSlogger;
  import org.apache.bookkeeper.slogger.Slogger;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import org.slf4j.MDC;
  
  /**
   * Slf4j implementation of slogger.
   */
  public class Slf4jSlogger extends AbstractSlogger {
      private ThreadLocal<List<String>> mdcKeysTls = new ThreadLocal<List<String>>() {
              @Override
              protected List<String> initialValue() {
                  return new ArrayList<>();
              }
          };
  
      private final Logger log;
  
      public Slf4jSlogger(Class<?> clazz) {
          this(clazz, Collections.emptyList());
      }
  
      Slf4jSlogger() {
          this(Slf4jSlogger.class);
      }
  
      Slf4jSlogger(Class<?> clazz, Iterable<Object> parent) {
          super(parent);
          this.log = LoggerFactory.getLogger(clazz);
      }
  
      @Override
      protected Slogger newSlogger(Optional<Class<?>> clazz, Iterable<Object> parent) {
          return new Slf4jSlogger(clazz.orElse(Slf4jSlogger.class), parent);
      }
  
      @Override
      protected void doLog(Level level, Enum<?> event, String message,
                           Throwable throwable, List<Object> keyValues) {
          List<String> mdcKeys = mdcKeysTls.get();
          mdcKeys.clear();
          try {
              if (event != null) {
                  MDC.put("event", event.toString());
                  mdcKeys.add("event");
              }
  
              for (int i = 0; i < keyValues.size(); i += 2) {
                  MDC.put(keyValues.get(i).toString(), keyValues.get(i + 1).toString());
                  mdcKeys.add(keyValues.get(i).toString());
              }
  
              String msg = message == null ? event.toString() : message;
              switch (level) {
              case INFO:
                  log.info(msg);
                  break;
              case WARN:
                  if (throwable != null) {
                      log.warn(msg, throwable);
                  } else {
                      log.warn(msg);
                  }
                  break;
              default:
              case ERROR:
                  if (throwable != null) {
                      log.error(msg, throwable);
                  } else {
                      log.error(msg);
                  }
                  break;
              }
          } finally {
              for (String key : mdcKeys) {
                  MDC.remove(key);
              }
              mdcKeys.clear();
          }
      }
  }
  