content: /*
   * Copyright (C) 2012-2023 52°North Spatial Information Research GmbH
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 as published
   * by the Free Software Foundation.
   *
   * If the program is linked with libraries which are licensed under one of
   * the following licenses, the combination of the program with the linked
   * library is not considered a "derivative work" of the program:
   *
   *     - Apache License, version 2.0
   *     - Apache Software License, version 1.0
   *     - GNU Lesser General Public License, version 3
   *     - Mozilla Public License, versions 1.0, 1.1 and 2.0
   *     - Common Development and Distribution License (CDDL), version 1.0
   *
   * Therefore the distribution of the program linked with libraries licensed
   * under the aforementioned licenses, is permitted by the copyright holders
   * if the distribution is compliant with both the GNU General Public
   * License version 2 and the aforementioned licenses.
   *
   * This program is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
   * Public License for more details.
   */
  package org.n52.sos.ds.hibernate.util;
  
  import java.util.Objects;
  import java.util.Optional;
  import java.util.function.Consumer;
  import java.util.function.Function;
  
  import org.hibernate.Session;
  import org.hibernate.SessionFactory;
  import org.hibernate.Transaction;
  
  import org.n52.janmayen.function.ThrowingConsumer;
  import org.n52.janmayen.function.ThrowingFunction;
  
  /**
   * TODO JavaDoc
   *
   * @author Christian Autermann
   */
  public abstract class AbstractSessionDao {
  
      private final SessionFactory sessionFactory;
  
      public AbstractSessionDao(SessionFactory sessionFactory) {
          this.sessionFactory = Objects.requireNonNull(sessionFactory);
      }
  
      protected <T, X extends Exception> Optional<T> throwingQueryOptional(ThrowingFunction<Session, T, X> query)
              throws X {
          T throwingQuery = throwingQuery(query);
          return Optional.ofNullable(throwingQuery);
      }
  
      protected <T, X extends Exception> T throwingQuery(ThrowingFunction<Session, T, X> query) throws X {
          Objects.requireNonNull(query);
          Session session = this.sessionFactory.openSession();
          Transaction tx;
          try {
              tx = getTransaction(session);
              T result = query.apply(session);
              tx.commit();
              return result;
          } finally {
              if (session != null) {
                  session.close();
              }
          }
      }
  
      private Transaction getTransaction(Session session) {
          return session.getTransaction().isActive() ? session.getTransaction() : session.beginTransaction();
      }
  
      protected <X extends Exception> void throwingStatement(ThrowingConsumer<Session, X> statement) throws X {
          Objects.requireNonNull(statement);
          throwingQuery(s -> {
              statement.accept(s);
              return null;
          });
      }
  
      @SuppressWarnings(value = "unchecked")
      protected <T> T query(Function<Session, T> query) {
          return throwingQuery(s -> query.apply(s));
      }
  
      @SuppressWarnings(value = "unchecked")
      protected <T> Optional<T> queryOptional(Function<Session, ?> query) {
          return throwingQueryOptional(s -> (T) query.apply(s));
      }
  
      protected void statement(Consumer<Session> statement) {
          Objects.requireNonNull(statement);
          query(s -> {
              statement.accept(s);
              return null;
          });
      }
  }
  