java - 如何使用 Joda Time 检查 DateTime 是否发生重复事件？

Question

我有一个 DateTime 表示重复事件的开始。 天(每日周期)将代表循环周期。我认为这种重复发生的事件永远不会停止。

from = "2013-06-27"  
period = 3 days
nextOccurence will be "2013-06-30", "2013-07-03", "2013-07-06", and so on.
"2013-07-03" is an occurence but "2013-07-04" isn't an occurence.

我想知道就性能而言确定 DateTime 是否发生重复事件的最佳方法是什么？从长远来看，程序将需要检查“2014-07-03”或“2015-07-03”是否出现。

Answer 1

这会在我的机器上在 180 毫秒内运行所有五项检查。或者每秒检查 27 次，即检查 300 年后的日期。

@Test
public void isOccurrence() {
    long startTime = System.currentTimeMillis();

    assertTrue(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2010, 1, 19, 0, 0)));
    assertFalse(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2010, 1, 18, 0, 0)));

    assertTrue(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2310, 1, 19, 0, 0)));
    assertFalse(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2310, 1, 20, 0, 0)));

    assertTrue(isOccurrence(new DateMidnight(2010, 1, 10), 3, new DateTime(2010, 1, 10, 0, 0)));

    System.out.println("elapsed=" + (System.currentTimeMillis() - startTime));
}

public boolean isOccurrence(DateMidnight startDate, int dayIncrement, DateTime testTime) {
    DateMidnight testDateMidnight = testTime.toDateMidnight();
    while (startDate.isBefore(testDateMidnight)) {
        startDate = startDate.plusDays(dayIncrement);
    }
    return startDate.equals(testDateMidnight);
}