Question

我正在寻找一种在Java中表示一组支持mathematical sets操作（联合，交集等）的独立时间段的方法。

请注意，我期望作为此类操作结果的集合将合并为连续时间段（尽可能多）。

示例：

假设我有两个假设集：

// imaginary constructor. numbers are unix times
TimeSet a = [(0,2), (3,6)]; 
TimeSet b = [(1,4), (5,7)];

现在让我们对它们执行一些操作：

a.union(b);     // result = [(0,7)]
a.minus(b);     // result = [(0,1), (4,5)]
b.minus(a);     // result = [(2,3), (6,7)]
a.intersect(b); // result = [(1,2), (3,4), (5,6)]
a.diff(b);      // result = [(0,1), (2,3), (4,5), (6,7)]

Answer 1

我发现的最好的是JodaTime的能力。

http://joda-time.sourceforge.net/apidocs/org/joda/time/Interval.html

该间隔允许使用＆＃34; abuts＆＃34;，＆＃34; gap＆＃34;和＆＃34;重叠＆＃34;等方法，这可能需要额外的条件算法。

Answer 2

由于缺乏对Java中此类间隔功能的一般支持，我决定使用我的库Time4J实现它：

Moment d0 = Moment.of(0, TimeScale.POSIX);
Moment d1 = Moment.of(1, TimeScale.POSIX);
Moment d2 = Moment.of(2, TimeScale.POSIX);
Moment d3 = Moment.of(3, TimeScale.POSIX);
Moment d4 = Moment.of(4, TimeScale.POSIX);
Moment d5 = Moment.of(5, TimeScale.POSIX);
Moment d6 = Moment.of(6, TimeScale.POSIX);
Moment d7 = Moment.of(7, TimeScale.POSIX);

MomentInterval i1 = MomentInterval.between(d0,  d2);
MomentInterval i2 = MomentInterval.between(d3,  d6);
IntervalCollection<Moment> a = IntervalCollection.onMomentAxis().plus(i1).plus(i2);

MomentInterval i3 = MomentInterval.between(d1,  d4);
MomentInterval i4 = MomentInterval.between(d5,  d7);
IntervalCollection<Moment> b = IntervalCollection.onMomentAxis().plus(i3).plus(i4);

System.out.println(a.plus(b));
// {[1970-01-01T00:00:00Z/1970-01-01T00:00:02Z),[1970-01-01T00:00:01Z/1970-01-01T00:00:04Z),[1970-01-01T00:00:03Z/1970-01-01T00:00:06Z),[1970-01-01T00:00:05Z/1970-01-01T00:00:07Z)}

System.out.println(a.union(b));
// {[1970-01-01T00:00:00Z/1970-01-01T00:00:07Z)}

System.out.println(a.minus(b));
// {[1970-01-01T00:00:00Z/1970-01-01T00:00:01Z),[1970-01-01T00:00:04Z/1970-01-01T00:00:05Z)}

System.out.println(b.minus(a));
// {[1970-01-01T00:00:02Z/1970-01-01T00:00:03Z),[1970-01-01T00:00:06Z/1970-01-01T00:00:07Z)}

System.out.println(a.intersect(b)); 
// {[1970-01-01T00:00:01Z/1970-01-01T00:00:02Z),[1970-01-01T00:00:03Z/1970-01-01T00:00:04Z),[1970-01-01T00:00:05Z/1970-01-01T00:00:06Z)}

System.out.println(a.xor(b)); // your diff operator
// {[1970-01-01T00:00:00Z/1970-01-01T00:00:01Z),[1970-01-01T00:00:02Z/1970-01-01T00:00:03Z),[1970-01-01T00:00:04Z/1970-01-01T00:00:05Z),[1970-01-01T00:00:06Z/1970-01-01T00:00:07Z)}

数学时间段？

2 个答案: