@Nullable
    public Long getExpireAfter(final TimeUnit timeUnit) {
        if (expireAfterSeconds == null) {
            return null;
        }
        return timeUnit.convert(expireAfterSeconds, TimeUnit.SECONDS);
    }
@Nullable
    public Long getExpireAfter(final TimeUnit timeUnit) {
        if (expireAfterSeconds == null) {
            return null;
        }
        return timeUnit.convert(expireAfterSeconds, TimeUnit.SECONDS);
    }
@ Nullable public Long getExpireAfter ( final TimeUnit timeUnit ) { if ( expireAfterSeconds == null ) { return null ; } return timeUnit . convert ( expireAfterSeconds , TimeUnit . SECONDS ) ; }
Gets the time to live for documents in the collection

@return the time to live for documents in the collection
@param timeUnit the time unit
@mongodb.driver.manual tutorial/expire-data TTL
Gets the time to live for documents in the collection