JodaTime年表缓存

BasicChronology

YearInfo

getYearInfo

YearInfo

/**
 * Caching class for first-day-of-year millis.
 *
 */
private static final class YearInfo {

    /**
     * Cache setup for first-day-of-year milliseconds.
     */
    private static final int CACHE_SIZE = 1 << 10;
    private static final int CACHE_MASK = CACHE_SIZE - 1;
    private static transient final YearInfo[] YEAR_INFO_CACHE = new YearInfo[CACHE_SIZE];

    /**
     * Storage variables for cache.
     */
    private final int year;
    private final long firstDayMillis;
    private final boolean isLeapYear;


    /**
     * Create the stored year information.
     * 
     * @param inYear The year to store info about.
     */
    private YearInfo(final int inYear) {
        this.firstDayMillis = calculateFirstDayOfYearMillis(inYear);
        this.isLeapYear = calculateLeapYear(inYear);
        this.year = inYear;
    }

    /**
     * Get year information.
     * 
     * @param year The given year.
     * 
     * @return Year information.
     */
    private static YearInfo getYearInfo(final int year) {
        YearInfo info = YEAR_INFO_CACHE[year & CACHE_MASK];
        if (info == null || info.year != year) {
            info = new YearInfo(year);
            YEAR_INFO_CACHE[year & CACHE_MASK] = info;
        }
        return info;
    }
}

BasicChronology