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.janusgraph.diskstorage.rdbms.dao;
  
  import org.janusgraph.diskstorage.rdbms.RdbmsTransaction;
  
  import javax.persistence.EntityManager;
  
  /**
   * Base DAO to access entities stored in RDBMS
   *
   */
  public abstract class BaseDao<T> {
      protected final EntityManager em;
  
      protected BaseDao(RdbmsTransaction trx) {
          this.em = trx.getEntityManager();
      }
  
      protected BaseDao(EntityManager em) {
          this.em = em;
      }
  
      public T create(T obj) {
          em.persist(obj);
  
          return obj;
      }
  
      protected Long toLong(Object obj) {
          return (obj instanceof Long) ? (Long) obj : null;
      }
  
      protected byte[] toByteArray(Object obj) {
          return (obj instanceof byte[]) ? (byte[]) obj : null;
      }
  }
  