net.fortuna.ical4j.transform.recurrence.ByMonthDayRule Maven / Gradle / Ivy

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A Java library for reading and writing iCalendar (*.ics) files
There is a newer version: 4.0.8
package net.fortuna.ical4j.transform.recurrence;

import net.fortuna.ical4j.model.Recur;
import net.fortuna.ical4j.model.Recur.Frequency;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.time.YearMonth;
import java.time.temporal.Temporal;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import java.util.Optional;
import java.util.function.Function;

import static java.time.temporal.ChronoField.DAY_OF_MONTH;
import static net.fortuna.ical4j.model.Recur.Frequency.MONTHLY;
import static net.fortuna.ical4j.model.Recur.Frequency.YEARLY;

/**
 * Applies BYMONTHDAY rules specified in this Recur instance to the specified date list. If no BYMONTHDAY rules are
 * specified the date list is returned unmodified.
 */
public class ByMonthDayRule extends AbstractDateExpansionRule {

    private transient Logger log = LoggerFactory.getLogger(ByMonthDayRule.class);

    private final List monthDayList;

    public ByMonthDayRule(List monthDayList, Frequency frequency) {
        super(frequency);
        this.monthDayList = monthDayList;
    }

    @Override
    public List transform(List dates) {
        if (monthDayList.isEmpty()) {
            return dates;
        }
        final List monthDayDates = new ArrayList<>();
        for (final T date : dates) {
            if (EnumSet.of(MONTHLY, YEARLY).contains(getFrequency())) {
                monthDayDates.addAll(new ExpansionFilter().apply(date));
            } else {
                Optional limit = new LimitFilter().apply(date);
                limit.ifPresent(monthDayDates::add);
            }
        }
        return monthDayDates;
    }

    private class LimitFilter implements Function> {
        @Override
        public Optional apply(T date) {
            if (monthDayList.contains(getDayOfMonth(date))) {
                return Optional.of(date);
            }
            return Optional.empty();
        }
    }

    private class ExpansionFilter implements Function> {
        @Override
        public List apply(T date) {
            List retVal = new ArrayList<>();
            // construct a list of possible month days..
            final int numDaysInMonth = YearMonth.of(getYear(date), getMonth(date)).lengthOfMonth();
            for (final int monthDay : monthDayList) {
                if (monthDay == 0 || monthDay < -numDaysInMonth || monthDay > numDaysInMonth) {
                    if (log.isTraceEnabled()) {
                        log.trace("Invalid day of month: " + monthDay);
                    }
                    continue;
                }
                T candidate;
                if (monthDay > 0) {
//                    if (numDaysInMonth < monthDay) {
//                        continue;
//                    }
                    candidate = withTemporalField(date, DAY_OF_MONTH, monthDay);
                } else {
                    if (numDaysInMonth < -monthDay) {
                        continue;
                    }
                    candidate = withTemporalField(date, DAY_OF_MONTH, numDaysInMonth + 1 + monthDay);
                }
                retVal.add(candidate);
            }
            return retVal;
        }
    }

    /**
     * @param stream
     * @throws IOException
     * @throws ClassNotFoundException
     */
    private void readObject(final java.io.ObjectInputStream stream) throws IOException, ClassNotFoundException {
        stream.defaultReadObject();
        log = LoggerFactory.getLogger(Recur.class);
    }
}