001/*
002 * This library is part of OpenCms -
003 * the Open Source Content Management System
004 *
005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
006 *
007 * This library is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * This library is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 * Lesser General Public License for more details.
016 *
017 * For further information about Alkacon Software GmbH & Co. KG, please see the
018 * company website: http://www.alkacon.com
019 *
020 * For further information about OpenCms, please see the
021 * project website: http://www.opencms.org
022 *
023 * You should have received a copy of the GNU Lesser General Public
024 * License along with this library; if not, write to the Free Software
025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
026 */
027
028package org.opencms.util;
029
030import org.opencms.i18n.CmsLocaleManager;
031
032import java.text.DateFormat;
033import java.text.ParseException;
034import java.text.SimpleDateFormat;
035import java.util.Calendar;
036import java.util.Date;
037import java.util.GregorianCalendar;
038import java.util.Locale;
039import java.util.TimeZone;
040
041/**
042 *
043 * Utilities to get and set formated dates in OpenCms.<p>
044 *
045 * @since 6.0.0
046 */
047public final class CmsDateUtil {
048
049    /** The "GMT" time zone, used when formatting http headers. */
050    protected static final TimeZone GMT_TIMEZONE = TimeZone.getTimeZone("GMT");
051
052    /** The default format to use when formatting http headers. */
053    protected static final DateFormat HEADER_DEFAULT = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US);
054
055    /** The default format to use when formatting old cookies. */
056    protected static final DateFormat OLD_COOKIE = new SimpleDateFormat("EEE, dd-MMM-yyyy HH:mm:ss z", Locale.US);
057
058    /**
059     * Hides the public constructor.<p>
060     */
061    private CmsDateUtil() {
062
063        // noop
064    }
065
066    /**
067     * Returns a formated date String from a Date value,
068     * the formatting based on the provided options.<p>
069     *
070     * @param date the Date object to format as String
071     * @param format the format to use, see {@link DateFormat} for possible values
072     * @param locale the locale to use
073     * @return the formatted date
074     */
075    public static String getDate(Date date, int format, Locale locale) {
076
077        DateFormat df = DateFormat.getDateInstance(format, locale);
078        return df.format(date);
079    }
080
081    /**
082     * Returns a formated date String form a timestamp value,
083     * the formatting based on the OpenCms system default locale
084     * and the {@link DateFormat#SHORT} date format.<p>
085     *
086     * @param time the time value to format as date
087     * @return the formatted date
088     */
089    public static String getDateShort(long time) {
090
091        return getDate(new Date(time), DateFormat.SHORT, CmsLocaleManager.getDefaultLocale());
092    }
093
094    /**
095     * Returns a formated date and time String from a Date value,
096     * the formatting based on the provided options.<p>
097     *
098     * @param date the Date object to format as String
099     * @param format the format to use, see {@link DateFormat} for possible values
100     * @param locale the locale to use
101     * @return the formatted date
102     */
103    public static String getDateTime(Date date, int format, Locale locale) {
104
105        DateFormat df = DateFormat.getDateInstance(format, locale);
106        DateFormat tf = DateFormat.getTimeInstance(format, locale);
107        StringBuffer buf = new StringBuffer();
108        buf.append(df.format(date));
109        buf.append(" ");
110        buf.append(tf.format(date));
111        return buf.toString();
112    }
113
114    /**
115     * Returns a formated date and time String form a timestamp value,
116     * the formatting based on the OpenCms system default locale
117     * and the {@link DateFormat#SHORT} date format.<p>
118     *
119     * @param time the time value to format as date
120     * @return the formatted date
121     */
122    public static String getDateTimeShort(long time) {
123
124        return getDateTime(new Date(time), DateFormat.SHORT, CmsLocaleManager.getDefaultLocale());
125    }
126
127    /**
128     * Returns the number of days passed since a specific date.<p>
129     *
130     * @param dateLastModified the date to compute the passed days from
131     *
132     * @return the number of days passed since a specific date
133     */
134    public static int getDaysPassedSince(Date dateLastModified) {
135
136        GregorianCalendar now = new GregorianCalendar();
137        GregorianCalendar lastModified = (GregorianCalendar)now.clone();
138        lastModified.setTimeInMillis(dateLastModified.getTime());
139        return (now.get(Calendar.DAY_OF_YEAR) - lastModified.get(Calendar.DAY_OF_YEAR))
140            + ((now.get(Calendar.YEAR) - lastModified.get(Calendar.YEAR)) * 365);
141    }
142
143    /**
144     * Returns a formated date and time String form a timestamp value based on the
145     * HTTP-Header date format.<p>
146     *
147     * @param time the time value to format as date
148     * @return the formatted date
149     */
150    synchronized public static String getHeaderDate(long time) {
151
152        if (HEADER_DEFAULT.getTimeZone() != GMT_TIMEZONE) {
153            // ensure GMT is used as time zone for the header generation
154            HEADER_DEFAULT.setTimeZone(GMT_TIMEZONE);
155        }
156
157        return HEADER_DEFAULT.format(new Date(time));
158    }
159
160    /**
161     * Returns a formatted date and time String form a timestamp value based on the
162     * (old) Netscape cookie date format.<p>
163     *
164     * @param time the time value to format as date
165     * @return the formatted date
166     */
167    synchronized public static String getOldCookieDate(long time) {
168
169        if (OLD_COOKIE.getTimeZone() != GMT_TIMEZONE) {
170            // ensure GMT is used as time zone for the header generation
171            OLD_COOKIE.setTimeZone(GMT_TIMEZONE);
172        }
173
174        try {
175            return OLD_COOKIE.format(new Date(time));
176        } catch (Throwable t) {
177            return OLD_COOKIE.format(new Date());
178        }
179    }
180
181    /**
182     * Returns the long value of a date created by the given integer values.<p>
183     *
184     * @param year the integer value of year
185     * @param month the integer value of month
186     * @param date the integer value of date
187     *
188     * @return the long value of a date created by the given integer values
189     */
190    public static long parseDate(int year, int month, int date) {
191
192        Calendar calendar = Calendar.getInstance();
193        calendar.set(year, month, date);
194        return calendar.getTime().getTime();
195    }
196
197    /**
198     * Parses a formated date and time string in HTTP-Header date format and returns the
199     * time value.<p>
200     *
201     * @param timestamp the timestamp in HTTP-Header date format
202     * @return time value as long
203     * @throws ParseException if parsing fails
204     */
205    synchronized public static long parseHeaderDate(String timestamp) throws ParseException {
206
207        return HEADER_DEFAULT.parse(timestamp).getTime();
208    }
209}