public static Specification<JpaTarget> isOverdue(final long overdueTimestamp) {
        return (targetRoot, query, cb) -> cb.lessThanOrEqualTo(targetRoot.get(JpaTarget_.lastTargetQuery),
                overdueTimestamp);
    }
public static Specification < JpaTarget > isOverdue ( final long overdueTimestamp ) { return ( targetRoot , query , cb ) -> cb . lessThanOrEqualTo ( targetRoot . get ( JpaTarget_ . lastTargetQuery ) , overdueTimestamp ) ; }
{@link Specification} for retrieving {@link Target}s that are overdue. A
target is overdue if it did not respond during the configured
intervals:<br>
<em>poll_itvl + overdue_itvl</em>

@param overdueTimestamp
the calculated timestamp to compare with the last respond of a
target (lastTargetQuery).<br>
The <code>overdueTimestamp</code> has to be calculated with
the following expression:<br>
<em>overdueTimestamp = nowTimestamp - poll_itvl -
overdue_itvl</em>

@return the {@link Target} {@link Specification}