/*
    * 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.lookup;
  
  import java.util.MissingResourceException;
  import java.util.ResourceBundle;
  
  import org.apache.logging.log4j.Logger;
  import org.apache.logging.log4j.Marker;
  import org.apache.logging.log4j.MarkerManager;
  import org.apache.logging.log4j.core.LogEvent;
  import org.apache.logging.log4j.core.config.plugins.Plugin;
  import org.apache.logging.log4j.status.StatusLogger;
  
  /**
   * Looks up keys from resource bundles.
   */
  @Plugin(name = "bundle", category = StrLookup.CATEGORY)
  public class ResourceBundleLookup extends AbstractLookup {
  
      private static final Logger LOGGER = StatusLogger.getLogger();
      private static final Marker LOOKUP = MarkerManager.getMarker("LOOKUP");
  
      /**
       * Looks up the value for the key in the format "BundleName:BundleKey".
       *
       * For example: "com.domain.messages:MyKey".
       *
       * @param event
       *            The current LogEvent.
       * @param key
       *            the key to be looked up, may be null
       * @return The value associated with the key.
       */
      @Override
      public String lookup(final LogEvent event, final String key) {
          if (key == null) {
              return null;
          }
          final String[] keys = key.split(":");
          final int keyLen = keys.length;
          if (keyLen != 2) {
              LOGGER.warn(LOOKUP, "Bad ResourceBundle key format [{}]. Expected format is BundleName:KeyName.", key);
              return null;
          }
          final String bundleName = keys[0];
          final String bundleKey = keys[1];
          try {
              // The ResourceBundle class caches bundles, no need to cache here.
              return ResourceBundle.getBundle(bundleName).getString(bundleKey);
          } catch (final MissingResourceException e) {
              LOGGER.warn(LOOKUP, "Error looking up ResourceBundle [{}].", bundleName, e);
              return null;
          }
      }
  }