package com.atlassian.scheduler.quartz2;
   
   import org.quartz.JobDetail;
   import org.quartz.JobPersistenceException;
   import org.quartz.impl.jdbcjobstore.JobStoreTX;
   import org.quartz.spi.OperableTrigger;
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
  import javax.annotation.Nullable;
  import java.sql.Connection;
  import java.util.concurrent.locks.ReentrantLock;
  
  import static com.atlassian.scheduler.core.util.LogWarn.logWarn;
  
  /**
   * Quartz breaks if a bad job class is seen during scheduler recovery (at startup),
   * leading to the scheduler failing to start.  This patches the normal {@code JobStoreTX}
   * to avoid the problem by logging a warning instead of failing to start the scheduler.
   */
  public class Quartz2HardenedJobStore extends JobStoreTX {
      private static final Logger LOG = LoggerFactory.getLogger(Quartz2HardenedJobStore.class);
  
      private final ReentrantLock recoverJobsLock = new ReentrantLock();
  
      @Override
      protected void recoverJobs() throws JobPersistenceException {
          recoverJobsLock.lock();
          try {
              super.recoverJobs();
          } finally {
              recoverJobsLock.unlock();
          }
      }
  
      @Override
      protected void storeTrigger(Connection conn, OperableTrigger newTrigger, @Nullable JobDetail job,
                                  boolean replaceExisting, String state, boolean forceState, boolean recovering)
              throws JobPersistenceException {
          try {
              super.storeTrigger(conn, newTrigger, job, replaceExisting, state, forceState, recovering);
          } catch (JobPersistenceException jpe) {
              // We don't actually expect this lock to ever be contended.  We just need to know if this thread
              // has traversed "recoverJobs" on the way here, and lock ownership is a convenient way to find out.
              if (!recoverJobsLock.isHeldByCurrentThread()) {
                  throw jpe;
              }
              logWarn(LOG, "Caught an exception storing trigger during scheduler recovery", jpe);
          }
      }
  }