【设计模式系列（一）】彻底搞懂工厂模式

/**
 * @author daijiyong
 */
public class CourseFactory {
    public static ICourse create(Class<? extends ICourse> clazz) {
        try {
            if (null != clazz) {
                return clazz.newInstance();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

/**
 * @author daijiyong
 */
public class Test {
    public static void main(String[] args) {
        ICourse course = CourseFactory.create(JavaCourse.class);
        if (course != null) {
            course.play();
        }
    }
}

    /**
     * Gets a calendar with the specified time zone and locale.
     * The <code>Calendar</code> returned is based on the current time
     * in the given time zone with the given locale.
     *
     * @param zone    the time zone to use
     * @param aLocale the locale for the week data
     * @return a Calendar.
     */
    public static Calendar getInstance(TimeZone zone,
                                       Locale aLocale) {
        return createCalendar(zone, aLocale);
    }
    private static Calendar createCalendar(TimeZone zone,
                                           Locale aLocale) {
        CalendarProvider provider =
                LocaleProviderAdapter.getAdapter(CalendarProvider.class, aLocale)
                        .getCalendarProvider();
        if (provider != null) {
            try {
                return provider.getInstance(zone, aLocale);
            } catch (IllegalArgumentException iae) {
                // fall back to the default instantiation
            }
        }
        Calendar cal = null;
        if (aLocale.hasExtensions()) {
            String caltype = aLocale.getUnicodeLocaleType("ca");
            if (caltype != null) {
                switch (caltype) {
                    case "buddhist":
                        cal = new BuddhistCalendar(zone, aLocale);
                        break;
                    case "japanese":
                        cal = new JapaneseImperialCalendar(zone, aLocale);
                        break;
                    case "gregory":
                        cal = new GregorianCalendar(zone, aLocale);
                        break;
                }
            }
        }
        if (cal == null) {
            // If no known calendar type is explicitly specified,
            // perform the traditional way to create a Calendar:
            // create a BuddhistCalendar for th_TH locale,
            // a JapaneseImperialCalendar for ja_JP_JP locale, or
            // a GregorianCalendar for any other locales.
            // NOTE: The language, country and variant strings are interned.
            if (aLocale.getLanguage() == "th" && aLocale.getCountry() == "TH") {
                cal = new BuddhistCalendar(zone, aLocale);
            } else if (aLocale.getVariant() == "JP" && aLocale.getLanguage() == "ja"
                    && aLocale.getCountry() == "JP") {
                cal = new JapaneseImperialCalendar(zone, aLocale);
            } else {
                cal = new GregorianCalendar(zone, aLocale);
            }
        }
        return cal;
    }

/**
 * @author daijiyong
 */
public class Test {
    public static void main(String[] args) {
        ICourseFactory courseFactory = new JavaCourseFactory();
        ICourse course = courseFactory.create();
        course.play();
    }
}