package org.alfresco.schedule;

import org.alfresco.repo.lock.JobLockService;
import org.quartz.JobExecutionContext;
import org.quartz.JobExecutionException;
import org.springframework.scheduling.quartz.QuartzJobBean;

/**
 * 
 * This class should be extended any time a scheduled job needs to be
 * implemented to be executed using
 * {@link org.alfresco.repo.lock.JobLockService JobLockService}. It makes the
 * cluster aware locking of the job transparent to the implementation. On the
 * job's spring {@link org.quartz.JobExecutionContext JobExecutionContext} it
 * will still always have to be passed as parameter the
 * {@link org.alfresco.repo.lock.JobLockService jobLockService}. The name to be
 * used for locking of the job is optional, if none is passed a name will be
 * composed using the simple name of the implementation class. In general if it
 * may make sense to have more than one job setup using the same class you
 * should always use a different name on each
 * {@link org.quartz.JobExecutionContext JobExecutionContext} to differentiate
 * the jobs, unless you want the lock to be shared between the different instances.
 * <p/>
 * The only method to be implemented when extending this class is {@link #executeJob(JobExecutionContext)}.
 * 
 * @author Rui Fernandes
 * @since 4.1.5
 */
public abstract class AbstractScheduledLockedJob extends QuartzJobBean
{
    private ScheduledJobLockExecuter locker;

    @Override
    protected synchronized final void executeInternal(final JobExecutionContext jobContext)
            throws JobExecutionException
    {
        if (locker == null)
        {
            JobLockService jobLockServiceBean = (JobLockService) jobContext.getJobDetail()
                    .getJobDataMap().get("jobLockService");
            if (jobLockServiceBean == null)
                throw new JobExecutionException("Missing setting for bean jobLockService");
            String name = (String) jobContext.getJobDetail().getJobDataMap().get("name");
            String jobName = name == null ? this.getClass().getSimpleName() : name;
            locker = new ScheduledJobLockExecuter(jobLockServiceBean, jobName, this);
        }
        locker.execute(jobContext);
    }

    /**
     * This is the method that should be implemented by any extension of the
     * abstract class. It won't need to worry about any lockings of the job and
     * can focus only on its specific task.
     * 
     * @param jobContext                context of the execution for retrieving services, etc
     * @throws JobExecutionException    if a job fails to execute
     */
    public abstract void executeJob(JobExecutionContext jobContext) throws JobExecutionException;
}