michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *   http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib.impl.cookie;
michael@0: 
michael@0: import java.lang.ref.SoftReference;
michael@0: import java.text.ParseException;
michael@0: import java.text.SimpleDateFormat;
michael@0: import java.util.Calendar;
michael@0: import java.util.Date;
michael@0: import java.util.HashMap;
michael@0: import java.util.Locale;
michael@0: import java.util.Map;
michael@0: import java.util.TimeZone;
michael@0: 
michael@0: import ch.boye.httpclientandroidlib.annotation.Immutable;
michael@0: 
michael@0: /**
michael@0:  * A utility class for parsing and formatting HTTP dates as used in cookies and
michael@0:  * other headers.  This class handles dates as defined by RFC 2616 section
michael@0:  * 3.3.1 as well as some other common non-standard formats.
michael@0:  *
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: @Immutable
michael@0: public final class DateUtils {
michael@0: 
michael@0:     /**
michael@0:      * Date format pattern used to parse HTTP date headers in RFC 1123 format.
michael@0:      */
michael@0:     public static final String PATTERN_RFC1123 = "EEE, dd MMM yyyy HH:mm:ss zzz";
michael@0: 
michael@0:     /**
michael@0:      * Date format pattern used to parse HTTP date headers in RFC 1036 format.
michael@0:      */
michael@0:     public static final String PATTERN_RFC1036 = "EEEE, dd-MMM-yy HH:mm:ss zzz";
michael@0: 
michael@0:     /**
michael@0:      * Date format pattern used to parse HTTP date headers in ANSI C
michael@0:      * <code>asctime()</code> format.
michael@0:      */
michael@0:     public static final String PATTERN_ASCTIME = "EEE MMM d HH:mm:ss yyyy";
michael@0: 
michael@0:     private static final String[] DEFAULT_PATTERNS = new String[] {
michael@0:         PATTERN_RFC1036,
michael@0:         PATTERN_RFC1123,
michael@0:         PATTERN_ASCTIME
michael@0:     };
michael@0: 
michael@0:     private static final Date DEFAULT_TWO_DIGIT_YEAR_START;
michael@0: 
michael@0:     public static final TimeZone GMT = TimeZone.getTimeZone("GMT");
michael@0: 
michael@0:     static {
michael@0:         Calendar calendar = Calendar.getInstance();
michael@0:         calendar.setTimeZone(GMT);
michael@0:         calendar.set(2000, Calendar.JANUARY, 1, 0, 0, 0);
michael@0:         calendar.set(Calendar.MILLISECOND, 0);
michael@0:         DEFAULT_TWO_DIGIT_YEAR_START = calendar.getTime();
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Parses a date value.  The formats used for parsing the date value are retrieved from
michael@0:      * the default http params.
michael@0:      *
michael@0:      * @param dateValue the date value to parse
michael@0:      *
michael@0:      * @return the parsed date
michael@0:      *
michael@0:      * @throws DateParseException if the value could not be parsed using any of the
michael@0:      * supported date formats
michael@0:      */
michael@0:     public static Date parseDate(String dateValue) throws DateParseException {
michael@0:         return parseDate(dateValue, null, null);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Parses the date value using the given date formats.
michael@0:      *
michael@0:      * @param dateValue the date value to parse
michael@0:      * @param dateFormats the date formats to use
michael@0:      *
michael@0:      * @return the parsed date
michael@0:      *
michael@0:      * @throws DateParseException if none of the dataFormats could parse the dateValue
michael@0:      */
michael@0:     public static Date parseDate(final String dateValue, String[] dateFormats)
michael@0:         throws DateParseException {
michael@0:         return parseDate(dateValue, dateFormats, null);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Parses the date value using the given date formats.
michael@0:      *
michael@0:      * @param dateValue the date value to parse
michael@0:      * @param dateFormats the date formats to use
michael@0:      * @param startDate During parsing, two digit years will be placed in the range
michael@0:      * <code>startDate</code> to <code>startDate + 100 years</code>. This value may
michael@0:      * be <code>null</code>. When <code>null</code> is given as a parameter, year
michael@0:      * <code>2000</code> will be used.
michael@0:      *
michael@0:      * @return the parsed date
michael@0:      *
michael@0:      * @throws DateParseException if none of the dataFormats could parse the dateValue
michael@0:      */
michael@0:     public static Date parseDate(
michael@0:         String dateValue,
michael@0:         String[] dateFormats,
michael@0:         Date startDate
michael@0:     ) throws DateParseException {
michael@0: 
michael@0:         if (dateValue == null) {
michael@0:             throw new IllegalArgumentException("dateValue is null");
michael@0:         }
michael@0:         if (dateFormats == null) {
michael@0:             dateFormats = DEFAULT_PATTERNS;
michael@0:         }
michael@0:         if (startDate == null) {
michael@0:             startDate = DEFAULT_TWO_DIGIT_YEAR_START;
michael@0:         }
michael@0:         // trim single quotes around date if present
michael@0:         // see issue #5279
michael@0:         if (dateValue.length() > 1
michael@0:             && dateValue.startsWith("'")
michael@0:             && dateValue.endsWith("'")
michael@0:         ) {
michael@0:             dateValue = dateValue.substring (1, dateValue.length() - 1);
michael@0:         }
michael@0: 
michael@0:         for (String dateFormat : dateFormats) {
michael@0:             SimpleDateFormat dateParser = DateFormatHolder.formatFor(dateFormat);
michael@0:             dateParser.set2DigitYearStart(startDate);
michael@0: 
michael@0:             try {
michael@0:                 return dateParser.parse(dateValue);
michael@0:             } catch (ParseException pe) {
michael@0:                 // ignore this exception, we will try the next format
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         // we were unable to parse the date
michael@0:         throw new DateParseException("Unable to parse the date " + dateValue);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Formats the given date according to the RFC 1123 pattern.
michael@0:      *
michael@0:      * @param date The date to format.
michael@0:      * @return An RFC 1123 formatted date string.
michael@0:      *
michael@0:      * @see #PATTERN_RFC1123
michael@0:      */
michael@0:     public static String formatDate(Date date) {
michael@0:         return formatDate(date, PATTERN_RFC1123);
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Formats the given date according to the specified pattern.  The pattern
michael@0:      * must conform to that used by the {@link SimpleDateFormat simple date
michael@0:      * format} class.
michael@0:      *
michael@0:      * @param date The date to format.
michael@0:      * @param pattern The pattern to use for formatting the date.
michael@0:      * @return A formatted date string.
michael@0:      *
michael@0:      * @throws IllegalArgumentException If the given date pattern is invalid.
michael@0:      *
michael@0:      * @see SimpleDateFormat
michael@0:      */
michael@0:     public static String formatDate(Date date, String pattern) {
michael@0:         if (date == null) throw new IllegalArgumentException("date is null");
michael@0:         if (pattern == null) throw new IllegalArgumentException("pattern is null");
michael@0: 
michael@0:         SimpleDateFormat formatter = DateFormatHolder.formatFor(pattern);
michael@0:         return formatter.format(date);
michael@0:     }
michael@0: 
michael@0:     /** This class should not be instantiated. */
michael@0:     private DateUtils() {
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * A factory for {@link SimpleDateFormat}s. The instances are stored in a
michael@0:      * threadlocal way because SimpleDateFormat is not threadsafe as noted in
michael@0:      * {@link SimpleDateFormat its javadoc}.
michael@0:      *
michael@0:      */
michael@0:     final static class DateFormatHolder {
michael@0: 
michael@0:         private static final ThreadLocal<SoftReference<Map<String, SimpleDateFormat>>>
michael@0:             THREADLOCAL_FORMATS = new ThreadLocal<SoftReference<Map<String, SimpleDateFormat>>>() {
michael@0: 
michael@0:             @Override
michael@0:             protected SoftReference<Map<String, SimpleDateFormat>> initialValue() {
michael@0:                 return new SoftReference<Map<String, SimpleDateFormat>>(
michael@0:                         new HashMap<String, SimpleDateFormat>());
michael@0:             }
michael@0: 
michael@0:         };
michael@0: 
michael@0:         /**
michael@0:          * creates a {@link SimpleDateFormat} for the requested format string.
michael@0:          *
michael@0:          * @param pattern
michael@0:          *            a non-<code>null</code> format String according to
michael@0:          *            {@link SimpleDateFormat}. The format is not checked against
michael@0:          *            <code>null</code> since all paths go through
michael@0:          *            {@link DateUtils}.
michael@0:          * @return the requested format. This simple dateformat should not be used
michael@0:          *         to {@link SimpleDateFormat#applyPattern(String) apply} to a
michael@0:          *         different pattern.
michael@0:          */
michael@0:         public static SimpleDateFormat formatFor(String pattern) {
michael@0:             SoftReference<Map<String, SimpleDateFormat>> ref = THREADLOCAL_FORMATS.get();
michael@0:             Map<String, SimpleDateFormat> formats = ref.get();
michael@0:             if (formats == null) {
michael@0:                 formats = new HashMap<String, SimpleDateFormat>();
michael@0:                 THREADLOCAL_FORMATS.set(
michael@0:                         new SoftReference<Map<String, SimpleDateFormat>>(formats));
michael@0:             }
michael@0: 
michael@0:             SimpleDateFormat format = formats.get(pattern);
michael@0:             if (format == null) {
michael@0:                 format = new SimpleDateFormat(pattern, Locale.US);
michael@0:                 format.setTimeZone(TimeZone.getTimeZone("GMT"));
michael@0:                 formats.put(pattern, format);
michael@0:             }
michael@0: 
michael@0:             return format;
michael@0:         }
michael@0: 
michael@0:     }
michael@0: 
michael@0: }