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.stats;
  
  import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
  import java.lang.reflect.Constructor;
  import java.lang.reflect.InvocationTargetException;
  import org.apache.commons.configuration2.Configuration;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * An umbrella class for loading stats provider.
   */
  public class Stats {
      static final Logger LOG = LoggerFactory.getLogger(Stats.class);
      public static final String STATS_PROVIDER_CLASS = "statsProviderClass";
  
      static StatsProvider prov = new NullStatsProvider();
  
      public static void loadStatsProvider(Configuration conf) {
          String className = conf.getString(STATS_PROVIDER_CLASS);
          loadStatsProvider(className);
      }
  
      public static void loadStatsProvider(String className) {
          if (className != null) {
              try {
                  Class cls = Class.forName(className);
                  @SuppressWarnings("unchecked")
                  Constructor<? extends StatsProvider> cons =
                      (Constructor<? extends StatsProvider>) cls.getDeclaredConstructor();
                  prov = cons.newInstance();
              } catch (ClassNotFoundException cnfe) {
                  LOG.error("Couldn't find configured class(" + className + ")", cnfe);
              } catch (NoSuchMethodException nsme) {
                  LOG.error("Couldn't find default constructor for class (" + className + ")", nsme);
              } catch (InstantiationException ie) {
                  LOG.error("Couldn't construct class (" + className + ")", ie);
              } catch (IllegalAccessException iae) {
                  LOG.error("Couldn't construct class (" + className + "),"
                            + " Is the constructor private?", iae);
              } catch (InvocationTargetException ite) {
                  LOG.error("Constructor threw an exception. It should not have.", ite);
              }
          }
      }
  
      @SuppressFBWarnings("EI_EXPOSE_REP2")
      public static StatsProvider get() {
          return prov;
      }
  }
  