/*
* $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk/module-client/src/main/java/org/apache/http/impl/cookie/DateUtils.java $
* $Revision: 677240 $
* $Date: 2008-07-16 04:25:47 -0700 (Wed, 16 Jul 2008) $
*
* ====================================================================
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.http.impl.cookie;
import java.lang.ref.SoftReference;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.TimeZone;
/**
* A utility class for parsing and formatting HTTP dates as used in cookies and
* other headers. This class handles dates as defined by RFC 2616 section
* 3.3.1 as well as some other common non-standard formats.
*
* @author Christopher Brown
* @author Michael Becke
*/
public final class DateUtils {
/**
* Date format pattern used to parse HTTP date headers in RFC 1123 format.
*/
public static final String PATTERN_RFC1123 = "EEE, dd MMM yyyy HH:mm:ss zzz";
/**
* Date format pattern used to parse HTTP date headers in RFC 1036 format.
*/
public static final String PATTERN_RFC1036 = "EEEE, dd-MMM-yy HH:mm:ss zzz";
/**
* Date format pattern used to parse HTTP date headers in ANSI C
* <code>asctime()</code> format.
*/
public static final String PATTERN_ASCTIME = "EEE MMM d HH:mm:ss yyyy";
private static final String[] DEFAULT_PATTERNS = new String[] {
PATTERN_RFC1036,
PATTERN_RFC1123,
PATTERN_ASCTIME
};
private static final Date DEFAULT_TWO_DIGIT_YEAR_START;
public static final TimeZone GMT = TimeZone.getTimeZone("GMT");
static {
Calendar calendar = Calendar.getInstance();
calendar.setTimeZone(GMT);
calendar.set(2000, Calendar.JANUARY, 1, 0, 0, 0);
calendar.set(Calendar.MILLISECOND, 0);
DEFAULT_TWO_DIGIT_YEAR_START = calendar.getTime();
}
/**
* Parses a date value. The formats used for parsing the date value are retrieved from
* the default http params.
*
* @param dateValue the date value to parse
*
* @return the parsed date
*
* @throws DateParseException if the value could not be parsed using any of the
* supported date formats
*/
public static Date parseDate(String dateValue) throws DateParseException {
return parseDate(dateValue, null, null);
}
/**
* Parses the date value using the given date formats.
*
* @param dateValue the date value to parse
* @param dateFormats the date formats to use
*
* @return the parsed date
*
* @throws DateParseException if none of the dataFormats could parse the dateValue
*/
public static Date parseDate(final String dateValue, String[] dateFormats)
throws DateParseException {
return parseDate(dateValue, dateFormats, null);
}
/**
* Parses the date value using the given date formats.
*
* @param dateValue the date value to parse
* @param dateFormats the date formats to use
* @param startDate During parsing, two digit years will be placed in the range
* <code>startDate</code> to <code>startDate + 100 years</code>. This value may
* be <code>null</code>. When <code>null</code> is given as a parameter, year
* <code>2000</code> will be used.
*
* @return the parsed date
*
* @throws DateParseException if none of the dataFormats could parse the dateValue
*/
public static Date parseDate(
String dateValue,
String[] dateFormats,
Date startDate
) throws DateParseException {
if (dateValue == null) {
throw new IllegalArgumentException("dateValue is null");
}
if (dateFormats == null) {
dateFormats = DEFAULT_PATTERNS;
}
if (startDate == null) {
startDate = DEFAULT_TWO_DIGIT_YEAR_START;
}
// trim single quotes around date if present
// see issue #5279
if (dateValue.length() > 1
&& dateValue.startsWith("'")
&& dateValue.endsWith("'")
) {
dateValue = dateValue.substring (1, dateValue.length() - 1);
}
for (String dateFormat : dateFormats) {
SimpleDateFormat dateParser = DateFormatHolder.formatFor(dateFormat);
dateParser.set2DigitYearStart(startDate);
try {
return dateParser.parse(dateValue);
} catch (ParseException pe) {
// ignore this exception, we will try the next format
}
}
// we were unable to parse the date
throw new DateParseException("Unable to parse the date " + dateValue);
}
/**
* Formats the given date according to the RFC 1123 pattern.
*
* @param date The date to format.
* @return An RFC 1123 formatted date string.
*
* @see #PATTERN_RFC1123
*/
public static String formatDate(Date date) {
return formatDate(date, PATTERN_RFC1123);
}
/**
* Formats the given date according to the specified pattern. The pattern
* must conform to that used by the {@link SimpleDateFormat simple date
* format} class.
*
* @param date The date to format.
* @param pattern The pattern to use for formatting the date.
* @return A formatted date string.
*
* @throws IllegalArgumentException If the given date pattern is invalid.
*
* @see SimpleDateFormat
*/
public static String formatDate(Date date, String pattern) {
if (date == null) throw new IllegalArgumentException("date is null");
if (pattern == null) throw new IllegalArgumentException("pattern is null");
SimpleDateFormat formatter = DateFormatHolder.formatFor(pattern);
return formatter.format(date);
}
/** This class should not be instantiated. */
private DateUtils() {
}
/**
* A factory for {@link SimpleDateFormat}s. The instances are stored in a
* threadlocal way because SimpleDateFormat is not threadsafe as noted in
* {@link SimpleDateFormat its javadoc}.
*
* @author Daniel Mueller
*/
final static class DateFormatHolder {
private static final ThreadLocal<SoftReference<Map<String, SimpleDateFormat>>>
THREADLOCAL_FORMATS = new ThreadLocal<SoftReference<Map<String, SimpleDateFormat>>>() {
@Override
protected SoftReference<Map<String, SimpleDateFormat>> initialValue() {
return new SoftReference<Map<String, SimpleDateFormat>>(
new HashMap<String, SimpleDateFormat>());
}
};
/**
* creates a {@link SimpleDateFormat} for the requested format string.
*
* @param pattern
* a non-<code>null</code> format String according to
* {@link SimpleDateFormat}. The format is not checked against
* <code>null</code> since all paths go through
* {@link DateUtils}.
* @return the requested format. This simple dateformat should not be used
* to {@link SimpleDateFormat#applyPattern(String) apply} to a
* different pattern.
*/
public static SimpleDateFormat formatFor(String pattern) {
SoftReference<Map<String, SimpleDateFormat>> ref = THREADLOCAL_FORMATS.get();
Map<String, SimpleDateFormat> formats = ref.get();
if (formats == null) {
formats = new HashMap<String, SimpleDateFormat>();
THREADLOCAL_FORMATS.set(
new SoftReference<Map<String, SimpleDateFormat>>(formats));
}
SimpleDateFormat format = formats.get(pattern);
if (format == null) {
format = new SimpleDateFormat(pattern, Locale.US);
format.setTimeZone(TimeZone.getTimeZone("GMT"));
formats.put(pattern, format);
}
return format;
}
}
}
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