fastdateformat.java

基于Jabber协议的即时消息服务器

/* ====================================================================
 * Trove - Copyright (c) 1997-2001 Walt Disney Internet Group
 * ====================================================================
 * The Tea Software License, Version 1.1
 *
 * Copyright (c) 2000 Walt Disney Internet Group. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Walt Disney Internet Group (http://opensource.go.com/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Tea", "TeaServlet", "Kettle", "Trove" and "BeanDoc" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Tea",
 *    "TeaServlet", "Kettle" or "Trove", nor may "Tea", "TeaServlet",
 *    "Kettle", "Trove" or "BeanDoc" appear in their name, without prior
 *    written permission of the Walt Disney Internet Group.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE WALT DISNEY INTERNET GROUP OR ITS
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * For more information about Tea, please see http://opensource.go.com/.
 */

package org.jivesoftware.util;

import java.util.Date;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;
import java.text.DateFormatSymbols;
import java.text.DateFormat;
import java.text.SimpleDateFormat;

/**
 * <p>Similar to {@link java.text.SimpleDateFormat}, but faster and thread-safe.
 * Only formatting is supported, but all patterns are compatible with
 * SimpleDateFormat.</p>
 *
 * <p>Note, this class is from the open source Tea project (http://sourceforge.net/projects/teatrove/).</p>
 *
 * @author Brian S O'Neill
 */
public class FastDateFormat {
    /** Style pattern */
    public static final Object
        FULL = new Integer(SimpleDateFormat.FULL),
        LONG = new Integer(SimpleDateFormat.LONG),
        MEDIUM = new Integer(SimpleDateFormat.MEDIUM),
        SHORT = new Integer(SimpleDateFormat.SHORT);

    private static final double LOG_10 = Math.log(10);

    private static String cDefaultPattern;
    private static TimeZone cDefaultTimeZone = TimeZone.getDefault();

    private static Map cTimeZoneDisplayCache = new HashMap();

    private static Map cInstanceCache = new HashMap(7);
    private static Map cDateInstanceCache = new HashMap(7);
    private static Map cTimeInstanceCache = new HashMap(7);
    private static Map cDateTimeInstanceCache = new HashMap(7);

    public static FastDateFormat getInstance() {
        return getInstance(getDefaultPattern(), null, null, null);
    }

    /**
     * @param pattern {@link java.text.SimpleDateFormat} compatible pattern
     */
    public static FastDateFormat getInstance(String pattern)
        throws IllegalArgumentException
    {
        return getInstance(pattern, null, null, null);
    }

    /**
     * @param pattern {@link java.text.SimpleDateFormat} compatible pattern
     * @param timeZone optional time zone, overrides time zone of formatted
     * date
     */
    public static FastDateFormat getInstance
        (String pattern, TimeZone timeZone) throws IllegalArgumentException
    {
        return getInstance(pattern, timeZone, null, null);
    }

    /**
     * @param pattern {@link java.text.SimpleDateFormat} compatible pattern
     * @param locale optional locale, overrides system locale
     */
    public static FastDateFormat getInstance
        (String pattern, Locale locale) throws IllegalArgumentException
    {
        return getInstance(pattern, null, locale, null);
    }

    /**
     * @param pattern {@link java.text.SimpleDateFormat} compatible pattern
     * @param symbols optional date format symbols, overrides symbols for
     * system locale
     */
    public static FastDateFormat getInstance
        (String pattern, DateFormatSymbols symbols)
        throws IllegalArgumentException
    {
        return getInstance(pattern, null, null, symbols);
    }

    /**
     * @param pattern {@link java.text.SimpleDateFormat} compatible pattern
     * @param timeZone optional time zone, overrides time zone of formatted
     * date
     * @param locale optional locale, overrides system locale
     */
    public static FastDateFormat getInstance
        (String pattern, TimeZone timeZone, Locale locale)
        throws IllegalArgumentException
    {
        return getInstance(pattern, timeZone, locale, null);
    }

    /**
     * @param pattern {@link java.text.SimpleDateFormat} compatible pattern
     * @param timeZone optional time zone, overrides time zone of formatted
     * date
     * @param locale optional locale, overrides system locale
     * @param symbols optional date format symbols, overrides symbols for
     * provided locale
     */
    public static synchronized FastDateFormat getInstance
        (String pattern, TimeZone timeZone, Locale locale,
         DateFormatSymbols symbols)
        throws IllegalArgumentException
    {
        Object key = pattern;

        if (timeZone != null) {
            key = new Pair(key, timeZone);
        }
        if (locale != null) {
            key = new Pair(key, locale);
        }
        if (symbols != null) {
            key = new Pair(key, symbols);
        }

        FastDateFormat format = (FastDateFormat)cInstanceCache.get(key);
        if (format == null) {
            if (locale == null) {
                locale = Locale.getDefault();
            }
            if (symbols == null) {
                symbols = new DateFormatSymbols(locale);
            }
            format = new FastDateFormat(pattern, timeZone, locale, symbols);
            cInstanceCache.put(key, format);
        }
        return format;
    }

    /**
     * @param style date style: FULL, LONG, MEDIUM, or SHORT
     * @param timeZone optional time zone, overrides time zone of formatted
     * date
     * @param locale optional locale, overrides system locale
     */
    public static synchronized FastDateFormat getDateInstance
        (Object style, TimeZone timeZone, Locale locale)
        throws IllegalArgumentException
    {
        Object key = style;

        if (timeZone != null) {
            key = new Pair(key, timeZone);
        }
        if (locale == null) {
            key = new Pair(key, locale);
        }

        FastDateFormat format = (FastDateFormat)cDateInstanceCache.get(key);

        if (format == null) {
            int ds;
            try {
                ds = ((Integer)style).intValue();
            }
            catch (ClassCastException e) {
                throw new IllegalArgumentException
                    ("Illegal date style: " + style);
            }

            if (locale == null) {
                locale = Locale.getDefault();
            }

            try {
                String pattern = ((SimpleDateFormat)DateFormat.getDateInstance(ds, locale)).toPattern();
                format = getInstance(pattern, timeZone, locale);
                cDateInstanceCache.put(key, format);
            }
            catch (ClassCastException e) {
                throw new IllegalArgumentException
                    ("No date pattern for locale: " + locale);
            }
        }

        return format;
    }

    /**
     * @param style time style: FULL, LONG, MEDIUM, or SHORT
     * @param timeZone optional time zone, overrides time zone of formatted
     * date
     * @param locale optional locale, overrides system locale
     */
    public static synchronized FastDateFormat getTimeInstance
        (Object style, TimeZone timeZone, Locale locale)
        throws IllegalArgumentException
    {
        Object key = style;

        if (timeZone != null) {
            key = new Pair(key, timeZone);
        }
        if (locale != null) {
            key = new Pair(key, locale);
        }

        FastDateFormat format = (FastDateFormat)cTimeInstanceCache.get(key);

        if (format == null) {
            int ts;
            try {
                ts = ((Integer)style).intValue();
            }
            catch (ClassCastException e) {
                throw new IllegalArgumentException
                    ("Illegal time style: " + style);
            }

            if (locale == null) {
                locale = Locale.getDefault();
            }

            try {
                String pattern = ((SimpleDateFormat)DateFormat.getTimeInstance(ts, locale)).toPattern();
                format = getInstance(pattern, timeZone, locale);
                cTimeInstanceCache.put(key, format);
            }
            catch (ClassCastException e) {
                throw new IllegalArgumentException
                    ("No date pattern for locale: " + locale);
            }
        }

        return format;
    }

    /**
     * @param dateStyle date style: FULL, LONG, MEDIUM, or SHORT
     * @param timeStyle time style: FULL, LONG, MEDIUM, or SHORT
     * @param timeZone optional time zone, overrides time zone of formatted
     * date
     * @param locale optional locale, overrides system locale
     */
    public static synchronized FastDateFormat getDateTimeInstance
        (Object dateStyle, Object timeStyle, TimeZone timeZone, Locale locale)
        throws IllegalArgumentException
    {
        Object key = new Pair(dateStyle, timeStyle);

        if (timeZone != null) {
            key = new Pair(key, timeZone);
        }
        if (locale != null) {
            key = new Pair(key, locale);
        }

        FastDateFormat format =
            (FastDateFormat)cDateTimeInstanceCache.get(key);

        if (format == null) {
            int ds;
            try {
                ds = ((Integer)dateStyle).intValue();
            }
            catch (ClassCastException e) {
                throw new IllegalArgumentException
                    ("Illegal date style: " + dateStyle);
            }

            int ts;
            try {
                ts = ((Integer)timeStyle).intValue();
            }
            catch (ClassCastException e) {
                throw new IllegalArgumentException
                    ("Illegal time style: " + timeStyle);
            }

            if (locale == null) {
                locale = Locale.getDefault();
            }

            try {
                String pattern = ((SimpleDateFormat)DateFormat.getDateTimeInstance(ds, ts, locale)).toPattern();
                format = getInstance(pattern, timeZone, locale);
                cDateTimeInstanceCache.put(key, format);
            }
            catch (ClassCastException e) {
                throw new IllegalArgumentException
                    ("No date time pattern for locale: " + locale);
            }
        }

        return format;
    }

    static synchronized String getTimeZoneDisplay(TimeZone tz,
                                                  boolean daylight,
                                                  int style,
                                                  Locale locale) {
        Object key = new TimeZoneDisplayKey(tz, daylight, style, locale);
        String value = (String)cTimeZoneDisplayCache.get(key);
        if (value == null) {
            // This is a very slow call, so cache the results.
            value = tz.getDisplayName(daylight, style, locale);
            cTimeZoneDisplayCache.put(key, value);
        }
        return value;
    }

    private static synchronized String getDefaultPattern() {
        if (cDefaultPattern == null) {
            cDefaultPattern = new SimpleDateFormat().toPattern();
        }
        return cDefaultPattern;
    }

    /**
     * Returns a list of Rules.
     */
    private static List parse(String pattern, TimeZone timeZone, Locale locale,
                              DateFormatSymbols symbols) {
        List rules = new ArrayList();

        String[] ERAs = symbols.getEras();
        String[] months = symbols.getMonths();
        String[] shortMonths = symbols.getShortMonths();
        String[] weekdays = symbols.getWeekdays();
        String[] shortWeekdays = symbols.getShortWeekdays();
        String[] AmPmStrings = symbols.getAmPmStrings();

        int length = pattern.length();
        int[] indexRef = new int[1];

        for (int i=0; i<length; i++) {
            indexRef[0] = i;
            String token = parseToken(pattern, indexRef);
            i = indexRef[0];

            int tokenLen = token.length();
            if (tokenLen == 0) {