content: package act.db;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * Licensed 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.
   * #L%
   */
  
  import act.util.LogSupportedDestroyableBase;
  import org.osgl.$;
  
  import java.util.HashMap;
  import java.util.Map;
  
  public class DbManager extends LogSupportedDestroyableBase {
      private Map<String, DbPlugin> plugins = new HashMap<>();
      private Map<Class, TimestampGenerator> timestampGeneratorMap = new HashMap<>();
  
      synchronized void register(DbPlugin plugin) {
          plugins.put(plugin.getClass().getCanonicalName(), plugin);
      }
  
      synchronized void register(TimestampGenerator timestampGenerator) {
          timestampGeneratorMap.put(timestampGenerator.timestampType(), timestampGenerator);
      }
  
      public synchronized DbPlugin plugin(String type) {
          return plugins.get(type);
      }
  
      public synchronized boolean hasPlugin() {
          return !plugins.isEmpty();
      }
  
      public synchronized <TIMESTAMP_TYPE> TimestampGenerator<TIMESTAMP_TYPE> timestampGenerator(Class<? extends TIMESTAMP_TYPE> c) {
          return $.cast(timestampGeneratorMap.get(c));
      }
  
      /**
       * Returns the plugin if there is only One plugin inside
       * the register, otherwise return {@code null}
       */
      public synchronized DbPlugin theSolePlugin() {
          if (plugins.size() == 1) {
              return plugins.values().iterator().next();
          } else {
              return null;
          }
      }
  }
  