聊聊PowerJob的TimingStrategyHandler

public interface TimingStrategyHandler {

    /**
     * 校验表达式
     *
     * @param timeExpression 时间表达式
     */
    void validate(String timeExpression);

    /**
     * 计算下次触发时间
     *
     * @param preTriggerTime 上次触发时间 (not null)
     * @param timeExpression 时间表达式
     * @param startTime      开始时间(include)
     * @param endTime        结束时间(include)
     * @return next trigger time
     */
    Long calculateNextTriggerTime(Long preTriggerTime, String timeExpression, Long startTime, Long endTime);

    /**
     * 支持的定时策略
     *
     * @return TimeExpressionType
     */
    TimeExpressionType supportType();


}

@Getter
@AllArgsConstructor
@ToString
public enum TimeExpressionType {

    API(1),
    CRON(2),
    FIXED_RATE(3),
    FIXED_DELAY(4),
    WORKFLOW(5),

    DAILY_TIME_INTERVAL(11);

    private final int v;

    public static final List<Integer> FREQUENT_TYPES = Collections.unmodifiableList(Lists.newArrayList(FIXED_RATE.v, FIXED_DELAY.v));
    /**
     * 首次计算触发时间时必须计算出一个有效值
     */
    public static final List<Integer> INSPECT_TYPES =  Collections.unmodifiableList(Lists.newArrayList(CRON.v, DAILY_TIME_INTERVAL.v));

    public static TimeExpressionType of(int v) {
        for (TimeExpressionType type : values()) {
            if (type.v == v) {
                return type;
            }
        }
        throw new IllegalArgumentException("unknown TimeExpressionType of " + v);
    }
}

public abstract class AbstractTimingStrategyHandler implements TimingStrategyHandler {
    @Override
    public void validate(String timeExpression) {
        // do nothing
    }

    @Override
    public Long calculateNextTriggerTime(Long preTriggerTime, String timeExpression, Long startTime, Long endTime) {
        // do nothing
        return null;
    }
}

@Component
public class ApiTimingStrategyHandler extends AbstractTimingStrategyHandler {
    @Override
    public TimeExpressionType supportType() {
        return TimeExpressionType.API;
    }
}

@Component
public class FixedRateTimingStrategyHandler extends AbstractTimingStrategyHandler {

    @Override
    public void validate(String timeExpression) {
        long delay;
        try {
            delay = Long.parseLong(timeExpression);
        } catch (Exception e) {
            throw new PowerJobException("invalid timeExpression!");
        }
        // 默认 120s ，超过这个限制应该使用考虑使用其他类型以减少资源占用
        int maxInterval = Integer.parseInt(System.getProperty(PowerJobDKey.FREQUENCY_JOB_MAX_INTERVAL, "120000"));
        if (delay > maxInterval) {
            throw new PowerJobException("the rate must be less than " + maxInterval + "ms");
        }
        if (delay <= 0) {
            throw new PowerJobException("the rate must be greater than 0 ms");
        }
    }

    @Override
    public Long calculateNextTriggerTime(Long preTriggerTime, String timeExpression, Long startTime, Long endTime) {
        long r = startTime != null && startTime > preTriggerTime
                ? startTime : preTriggerTime + Long.parseLong(timeExpression);
        return endTime != null && endTime < r ? null : r;
    }

    @Override
    public TimeExpressionType supportType() {
        return TimeExpressionType.FIXED_RATE;
    }
}

@Component
public class FixedDelayTimingStrategyHandler extends AbstractTimingStrategyHandler {

    @Override
    public void validate(String timeExpression) {
        long delay;
        try {
            delay = Long.parseLong(timeExpression);
        } catch (Exception e) {
            throw new PowerJobException("invalid timeExpression!");
        }
        // 默认 120s ，超过这个限制应该考虑使用其他类型以减少资源占用
        int maxInterval = Integer.parseInt(System.getProperty(PowerJobDKey.FREQUENCY_JOB_MAX_INTERVAL, "120000"));
        if (delay > maxInterval) {
            throw new PowerJobException("the delay must be less than " + maxInterval + "ms");
        }
        if (delay <= 0) {
            throw new PowerJobException("the delay must be greater than 0 ms");
        }
    }

    @Override
    public TimeExpressionType supportType() {
        return TimeExpressionType.FIXED_DELAY;
    }
}

@Component
public class WorkflowTimingStrategyHandler extends AbstractTimingStrategyHandler {
    @Override
    public TimeExpressionType supportType() {
        return TimeExpressionType.WORKFLOW;
    }
}

@Component
public class CronTimingStrategyHandler implements TimingStrategyHandler {

    private final CronParser cronParser;

    /**
     * @see CronDefinitionBuilder#instanceDefinitionFor
     * <p>
     * Enhanced quartz cron，Support for specifying both a day-of-week and a day-of-month parameter.
     * https://github.com/PowerJob/PowerJob/issues/382
     */
    public CronTimingStrategyHandler() {
        CronDefinition cronDefinition = CronDefinitionBuilder.defineCron()
                .withSeconds().withValidRange(0, 59).and()
                .withMinutes().withValidRange(0, 59).and()
                .withHours().withValidRange(0, 23).and()
                .withDayOfMonth().withValidRange(1, 31).supportsL().supportsW().supportsLW().supportsQuestionMark().and()
                .withMonth().withValidRange(1, 12).and()
                .withDayOfWeek().withValidRange(1, 7).withMondayDoWValue(2).supportsHash().supportsL().supportsQuestionMark().and()
                .withYear().withValidRange(1970, 2099).withStrictRange().optional().and()
                .instance();
        this.cronParser = new CronParser(cronDefinition);
    }


    @Override
    public void validate(String timeExpression) {
        cronParser.parse(timeExpression);
    }

    @Override
    public Long calculateNextTriggerTime(Long preTriggerTime, String timeExpression, Long startTime, Long endTime) {
        Cron cron = cronParser.parse(timeExpression);
        ExecutionTime executionTime = ExecutionTime.forCron(cron);
        if (startTime != null && startTime > System.currentTimeMillis() && preTriggerTime < startTime) {
            // 需要计算出离 startTime 最近的一次真正的触发时间
            Optional<ZonedDateTime> zonedDateTime = executionTime.lastExecution(ZonedDateTime.ofInstant(Instant.ofEpochMilli(startTime), ZoneId.systemDefault()));
            preTriggerTime = zonedDateTime.map(dateTime -> dateTime.toEpochSecond() * 1000).orElse(startTime);
        }
        Instant instant = Instant.ofEpochMilli(preTriggerTime);
        ZonedDateTime preZonedDateTime = ZonedDateTime.ofInstant(instant, ZoneId.systemDefault());
        Optional<ZonedDateTime> opt = executionTime.nextExecution(preZonedDateTime);
        if (opt.isPresent()) {
            long nextTriggerTime = opt.get().toEpochSecond() * 1000;
            if (endTime != null && endTime < nextTriggerTime) {
                return null;
            }
            return nextTriggerTime;
        }
        return null;
    }

    @Override
    public TimeExpressionType supportType() {
        return TimeExpressionType.CRON;
    }
}

@Component
public class DailyTimeIntervalStrategyHandler implements TimingStrategyHandler {

    /**
     * 使用中国星期！！！
     */
    private static final Set<Integer> ALL_DAY = Sets.newHashSet(1, 2, 3, 4, 5, 6, 7);

    @Override
    public TimeExpressionType supportType() {
        return TimeExpressionType.DAILY_TIME_INTERVAL;
    }

    @Override
    @SneakyThrows
    public void validate(String timeExpression) {
        DailyTimeIntervalExpress ep = JsonUtils.parseObject(timeExpression, DailyTimeIntervalExpress.class);
        CommonUtils.requireNonNull(ep.interval, "interval can't be null or empty in DailyTimeIntervalExpress");
        CommonUtils.requireNonNull(ep.startTimeOfDay, "startTimeOfDay can't be null or empty in DailyTimeIntervalExpress");
        CommonUtils.requireNonNull(ep.endTimeOfDay, "endTimeOfDay can't be null or empty in DailyTimeIntervalExpress");

        TimeOfDay startTime = TimeOfDay.from(ep.startTimeOfDay);
        TimeOfDay endTime = TimeOfDay.from(ep.endTimeOfDay);

        if (endTime.before(startTime)) {
            throw new IllegalArgumentException("endTime should after startTime!");
        }

        if (StringUtils.isNotEmpty(ep.intervalUnit)) {
            TimeUnit.valueOf(ep.intervalUnit);
        }
    }

    @Override
    @SneakyThrows
    public Long calculateNextTriggerTime(Long preTriggerTime, String timeExpression, Long startTime, Long endTime) {
        DailyTimeIntervalExpress ep = JsonUtils.parseObject(timeExpression, DailyTimeIntervalExpress.class);

        // 未开始状态下，用起点算调度时间
        if (startTime != null && startTime > System.currentTimeMillis() && preTriggerTime < startTime) {
            return calculateInRangeTime(startTime, ep);
        }

        // 间隔时间
        TimeUnit timeUnit = Optional.ofNullable(ep.intervalUnit).map(TimeUnit::valueOf).orElse(TimeUnit.SECONDS);
        long interval = timeUnit.toMillis(ep.interval);

        Long ret = calculateInRangeTime(preTriggerTime + interval, ep);
        if (ret == null || ret <= Optional.ofNullable(endTime).orElse(Long.MAX_VALUE)) {
            return ret;
        }
        return null;
    }

    /**
     * 计算最近一次在范围中的时间
     * @param time 当前时间基准，可能直接返回该时间作为结果
     * @param ep 表达式
     * @return 最近一次在范围中的时间
     */
    static Long calculateInRangeTime(Long time, DailyTimeIntervalExpress ep) {

        Calendar calendar = Calendar.getInstance();
        calendar.setTime(new Date(time));

        int year = calendar.get(Calendar.YEAR);
        // 月份 + 1，转为熟悉的 1～12 月
        int month = calendar.get(Calendar.MONTH) + 1;
        int day = calendar.get(Calendar.DAY_OF_MONTH);

        // 判断是否符合"日"的执行条件
        int week = TimeUtils.calculateWeek(year, month, day);
        Set<Integer> targetDays = CollectionUtils.isEmpty(ep.daysOfWeek) ? ALL_DAY : ep.daysOfWeek;
        // 未包含情况下，将时间改写为符合条件日的 00:00 分，重新开始递归（这部分应该有性能更优的写法，不过这个调度模式应该很难触发瓶颈，先简单好用的实现）
        if (!targetDays.contains(week)) {
            simpleSetCalendar(calendar, 0, 0, 0);
            Date tomorrowZero = DateUtils.addDays(calendar.getTime(), 1);
            return calculateInRangeTime(tomorrowZero.getTime(), ep);
        }

        // 范围的开始时间
        TimeOfDay rangeStartTime = TimeOfDay.from(ep.startTimeOfDay);
        simpleSetCalendar(calendar, rangeStartTime.getHour(), rangeStartTime.getMinute(), rangeStartTime.getSecond());
        long todayStartTs = calendar.getTimeInMillis();

        // 未开始
        if (time < todayStartTs) {
            return todayStartTs;
        }

        TimeOfDay rangeEndTime = TimeOfDay.from(ep.endTimeOfDay);
        simpleSetCalendar(calendar, rangeEndTime.getHour(), rangeEndTime.getMinute(), rangeEndTime.getSecond());
        long todayEndTs = calendar.getTimeInMillis();

        // 范围之间
        if (time <= todayEndTs) {
            return time;
        }

        // 已结束，重新计算第二天时间
        simpleSetCalendar(calendar, 0, 0, 0);
        return calculateInRangeTime(DateUtils.addDays(calendar.getTime(), 1).getTime(), ep);
    }

    //......
}    

@Slf4j
@Service
public class TimingStrategyService {

    private static final int NEXT_N_TIMES = 5;

    private static final List<String> TIPS = Collections.singletonList("It is valid, but has not trigger time list!");


    private final Map<TimeExpressionType, TimingStrategyHandler> strategyContainer;

    public TimingStrategyService(List<TimingStrategyHandler> timingStrategyHandlers) {
        // init
        strategyContainer = new EnumMap<>(TimeExpressionType.class);
        for (TimingStrategyHandler timingStrategyHandler : timingStrategyHandlers) {
            strategyContainer.put(timingStrategyHandler.supportType(), timingStrategyHandler);
        }
    }

    /**
     * 计算接下来几次的调度时间
     *
     * @param timeExpressionType 定时表达式类型
     * @param timeExpression     表达式
     * @param startTime          起始时间(include)
     * @param endTime            结束时间(include)
     * @return 调度时间列表
     */
    public List<String> calculateNextTriggerTimes(TimeExpressionType timeExpressionType, String timeExpression, Long startTime, Long endTime) {

        TimingStrategyHandler timingStrategyHandler = getHandler(timeExpressionType);
        List<Long> triggerTimeList = new ArrayList<>(NEXT_N_TIMES);
        Long nextTriggerTime = System.currentTimeMillis();
        do {
            nextTriggerTime = timingStrategyHandler.calculateNextTriggerTime(nextTriggerTime, timeExpression, startTime, endTime);
            if (nextTriggerTime == null) {
                break;
            }
            triggerTimeList.add(nextTriggerTime);
        } while (triggerTimeList.size() < NEXT_N_TIMES);

        if (triggerTimeList.isEmpty()) {
            return TIPS;
        }
        return triggerTimeList.stream().map(t -> DateFormatUtils.format(t, OmsConstant.TIME_PATTERN)).collect(Collectors.toList());
    }

    /**
     * 计算下次的调度时间
     *
     * @param preTriggerTime     上次触发时间(nullable)
     * @param timeExpressionType 定时表达式类型
     * @param timeExpression     表达式
     * @param startTime          起始时间(include)
     * @param endTime            结束时间(include)
     * @return 下次的调度时间
     */
    public Long calculateNextTriggerTime(Long preTriggerTime, TimeExpressionType timeExpressionType, String timeExpression, Long startTime, Long endTime) {
        if (preTriggerTime == null || preTriggerTime < System.currentTimeMillis()) {
            preTriggerTime = System.currentTimeMillis();
        }
        return getHandler(timeExpressionType).calculateNextTriggerTime(preTriggerTime, timeExpression, startTime, endTime);
    }


    /**
     * 计算下次的调度时间并检查校验规则
     *
     * @param timeExpressionType 定时表达式类型
     * @param timeExpression     表达式
     * @param startTime          起始时间(include)
     * @param endTime            结束时间(include)
     * @return 下次的调度时间
     */
    public Long calculateNextTriggerTimeWithInspection( TimeExpressionType timeExpressionType, String timeExpression, Long startTime, Long endTime) {
        Long nextTriggerTime = calculateNextTriggerTime(null, timeExpressionType, timeExpression, startTime, endTime);
        if (TimeExpressionType.INSPECT_TYPES.contains(timeExpressionType.getV()) && nextTriggerTime == null) {
            throw new PowerJobException("time expression is out of date: " + timeExpression);
        }
        return nextTriggerTime;
    }


    public void validate(TimeExpressionType timeExpressionType, String timeExpression, Long startTime, Long endTime) {
        if (endTime != null) {
            if (endTime <= System.currentTimeMillis()) {
                throw new PowerJobException("lifecycle is out of date!");
            }
            if (startTime != null && startTime > endTime) {
                throw new PowerJobException("lifecycle is invalid! start time must earlier then end time.");
            }
        }
        getHandler(timeExpressionType).validate(timeExpression);
    }


    private TimingStrategyHandler getHandler(TimeExpressionType timeExpressionType) {
        TimingStrategyHandler timingStrategyHandler = strategyContainer.get(timeExpressionType);
        if (timingStrategyHandler == null) {
            throw new PowerJobException("No matching TimingStrategyHandler for this TimeExpressionType:" + timeExpressionType);
        }
        return timingStrategyHandler;
    }

}