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.cache;
  
  import java.util.Objects;
  import java.util.Set;
  import java.util.concurrent.locks.Lock;
  import java.util.concurrent.locks.ReentrantLock;
  
  import org.hibernate.HibernateException;
  import org.hibernate.Session;
  import org.n52.series.db.old.HibernateSessionStore;
  import org.n52.shetland.util.CollectionHelper;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   *
   * @author <a href="mailto:c.autermann@52north.org">Christian Autermann</a>
   *
   * @since 4.0.0
   */
  public class ThreadLocalSessionFactory {
  
      private static final Logger LOGGER = LoggerFactory.getLogger(ThreadLocalSessionFactory.class);
      private final HibernateSessionStore sessionStore;
      private final Lock lock = new ReentrantLock();
      private final Set<Session> createdSessions = CollectionHelper.synchronizedSet();
      private final ThreadLocal<Session> threadLocal;
      private boolean closed;
  
      public ThreadLocalSessionFactory(HibernateSessionStore sessionStore) {
          this.sessionStore = Objects.requireNonNull(sessionStore);
          this.threadLocal = ThreadLocal.withInitial(this::createConnection);
      }
  
      private Session createConnection() {
          try {
              return this.sessionStore.getSession();
          } catch (HibernateException he) {
              LOGGER.error("Error while getting initialValue for ThreadLocalSessionFactory!", he);
              throw new RuntimeException(he);
          }
      }
  
      public Session getSession() {
          lock.lock();
          try {
              if (isClosed()) {
                  throw new IllegalStateException("factory already closed");
              }
              Session session = this.threadLocal.get();
              this.createdSessions.add(session);
              return session;
          } finally {
              lock.unlock();
          }
      }
  
      public void close() {
          setClosed();
          returnSessions();
      }
  
      protected void setClosed() {
          this.lock.lock();
          try {
              this.closed = true;
          } finally {
              this.lock.unlock();
          }
      }
  
      protected boolean isClosed() {
          this.lock.lock();
          try {
              return this.closed;
          } finally {
              this.lock.unlock();
          }
      }
  
      protected void returnSessions() {
          this.lock.lock();
          try {
              this.createdSessions
                  .forEach(this.sessionStore::returnSession);
          } catch (Exception e) {
              LOGGER.error("Error while returning connection after cache update!", e);
          } finally {
              this.lock.unlock();
          }
      }
  }
  