PublicationMigration.java

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/*
 * Turró i Cutiller Foundation. License notice.
 * Copyright (C) 2023 Lluis Turró Cutiller <http://www.turro.org/>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
package org.turro.publication.command;
 
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.ReentrantLock;
import java.util.stream.Stream;
import org.turro.jpa.Dao;
import org.turro.jpa.DaoUtil;
import org.turro.log.WebLoggers;
import org.turro.publication.db.PublicationPU;
import org.turro.publication.entity.PublicationCategory;
import org.turro.publication.entity.PublicationConstraint;
import org.turro.string.Strings;
 
public class PublicationMigration  implements Runnable {
  
  public static void migrate() {
    PublicationMigration migration = new PublicationMigration();
    if(migration.isNecessary()) new Thread(migration, "ElephantPublication migration").start();
  }
 
  private boolean isNecessary() {
    return DaoUtil.isEmpty(dao, "PublicationConstraint");
  }
 
  private void start() {
    try(Stream<PublicationCategory> categories = new PublicationPU().stream(PublicationCategory.class, "select p from PublicationCategory p")) {
      categories.forEach((category) -> {
        if(!Strings.isBlank(category.getConditionedBy())) {
          PublicationConstraint constraint = new PublicationConstraint();
          constraint.setPublicationCategory(category);
          constraint.setKeyId(category.getConditionedBy());
          constraint.setOptional(true);
          category.getConstraints().add(constraint);
          dao.saveObject(category);
        }
      });
    }
  }
 
  private final Dao dao;
  
  private PublicationMigration() {
    this.dao = new PublicationPU();
  }
 
  private static final ReentrantLock LOCK = new ReentrantLock();
 
  @Override
  public void run() {
    if(!LOCK.isLocked()) {
      try {
        if(LOCK.tryLock(0, TimeUnit.SECONDS)) {
          try {
            if(isNecessary()) {
              start();
            }
          } finally {
            LOCK.unlock();
          }
        }
      } catch (InterruptedException ex) {
        WebLoggers.severe(this).exception(ex).log();
      }
    }
  }
  
}