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.atlas.hive.hook;
  
  
  import org.apache.atlas.plugin.classloader.AtlasPluginClassLoader;
  import org.apache.hadoop.hive.ql.hooks.ExecuteWithHookContext;
  import org.apache.hadoop.hive.ql.hooks.HookContext;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Hive hook used for atlas entity registration.
   */
  public class HiveHook implements ExecuteWithHookContext {
      private static final Logger LOG = LoggerFactory.getLogger(HiveHook.class);
  
      private static final String ATLAS_PLUGIN_TYPE = "hive";
      private static final String ATLAS_HIVE_HOOK_IMPL_CLASSNAME = "org.apache.atlas.hive.hook.HiveHook";
  
      private AtlasPluginClassLoader atlasPluginClassLoader = null;
      private ExecuteWithHookContext hiveHookImpl = null;
  
      public HiveHook() {
          this.initialize();
      }
  
      @Override
      public void run(final HookContext hookContext) throws Exception {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveHook.run({})", hookContext);
          }
  
          try {
              activatePluginClassLoader();
              hiveHookImpl.run(hookContext);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveHook.run({})", hookContext);
          }
      }
  
      private void initialize() {
          if (LOG.isDebugEnabled()) {
              LOG.debug("==> HiveHook.initialize()");
          }
  
          try {
              atlasPluginClassLoader = AtlasPluginClassLoader.getInstance(ATLAS_PLUGIN_TYPE, this.getClass());
  
              @SuppressWarnings("unchecked")
              Class<ExecuteWithHookContext> cls = (Class<ExecuteWithHookContext>) Class
                      .forName(ATLAS_HIVE_HOOK_IMPL_CLASSNAME, true, atlasPluginClassLoader);
  
              activatePluginClassLoader();
  
              hiveHookImpl = cls.newInstance();
          } catch (Exception excp) {
              LOG.error("Error instantiating Atlas hook implementation", excp);
          } finally {
              deactivatePluginClassLoader();
          }
  
          if (LOG.isDebugEnabled()) {
              LOG.debug("<== HiveHook.initialize()");
          }
      }
  
      private void activatePluginClassLoader() {
          if (atlasPluginClassLoader != null) {
              atlasPluginClassLoader.activate();
          }
      }
  
      private void deactivatePluginClassLoader() {
          if (atlasPluginClassLoader != null) {
              atlasPluginClassLoader.deactivate();
          }
      }
  }
  