Java日期迭代器工厂，具有规定如何计算间隔的规则

问题描述

我正在寻找一个Java类，在那里我可以指定一组日期规则，例如每3个星期日和每隔一个星期一的第一次出现。我想要能够得到类似无限迭代器的东西（.next（）将返回匹配规则集的下一个日期）。

I am looking for a Java class where I can specify a set of date rules, such as "every 3rd sunday" and "the first occurrence of a monday every second month". I want to be able to get something like an infinite iterator out of it (.next() would return the next date matching the rules set).

我想我'能够自己建立 - 但日历是一件麻烦，感觉就像已经存在的东西一样。我讨厌成为一个重新开发一个crappier轮。

I think I'd be able to build it myself - but calendars are a hassle, and it feels like something similar should exist already. I hate being the one to reinvent a crappier wheel.

有人知道这样的事情吗？我一直在看JODA，它似乎为此打下了基础，但似乎没有给出我想要的全部功能。

Is anyone aware of something like this? I have been looking at JODA, and it seems to lay the groundwork for it, but does not appear to give the full functionality I want..

推荐答案

我认为没有任何容易的迭代器用于joda-time或Java Calendar API，但是对于joda来说，这么简单就可以了。例如，在几个月后，我重新熟悉自己，我在大约10分钟内完成了这个工作：

I don't think there's any readily made iterators for joda-time or Java Calendar API for that matter, however with joda it's so easy that you should just go with it. For example after re-familiarizing myself with joda after a few months pause I made this in about 10 minutes:

public class InstantIterator implements Iterator<Instant>,
                                        Iterable<Instant> {

    private Instant current;
    private final Instant original;
    private Duration skip;
    private List<Instant> skipThese;

    public InstantIterator(Instant startFrom, Duration skip) {
        this.current = original = startFrom;
        this.skip = skip;
        skipThese = new Vector<Instant>();
    }

    public boolean hasNext() {
        return true;
    }

    public Instant next() {
        Instant currentNext = current.toInstant();
        current = current.plus(skip);
        while (skipThese.contains(currentNext)) {
            currentNext = current.toInstant();
            current = current.plus(skip);
        }
        return currentNext;
    }

    public void remove() {
        skipThese.add(current.toInstant());
    }

    public Iterator<Instant> iterator() {
        return this;
    }

    public void rewind() {
        current = original.toInstant();
    }

    public void resetRemoved() {
        skipThese.clear();
    }

    public void resetIterator() {
        rewind();
        resetRemoved();
    }
}

Joda时间真棒： - ）

Joda Time is awesome :-)

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