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Apache HttpComponents Client
/*
* ====================================================================
* 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
* asctime() format.
*/
public static final String PATTERN_ASCTIME = "EEE MMM d HH:mm:ss yyyy";
private static final String[] DEFAULT_PATTERNS = new String[] {
PATTERN_RFC1123,
PATTERN_RFC1036,
PATTERN_ASCTIME
};
private static final Date DEFAULT_TWO_DIGIT_YEAR_START;
public static final TimeZone GMT = TimeZone.getTimeZone("GMT");
static {
final 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 or null if input could not be parsed
*/
public static Date parseDate(final String dateValue) {
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 or null if input could not be parsed
*/
public static Date parseDate(final String dateValue, final String[] dateFormats) {
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
* startDate to startDate + 100 years. This value may
* be null. When null is given as a parameter, year
* 2000 will be used.
*
* @return the parsed date or null if input could not be parsed
*/
public static Date parseDate(
final String dateValue,
final String[] dateFormats,
final Date startDate) {
Args.notNull(dateValue, "Date value");
final String[] localDateFormats = dateFormats != null ? dateFormats : DEFAULT_PATTERNS;
final Date localStartDate = startDate != null ? startDate : DEFAULT_TWO_DIGIT_YEAR_START;
String v = dateValue;
// trim single quotes around date if present
// see issue #5279
if (v.length() > 1 && v.startsWith("'") && v.endsWith("'")) {
v = v.substring (1, v.length() - 1);
}
for (final String dateFormat : localDateFormats) {
final SimpleDateFormat dateParser = DateFormatHolder.formatFor(dateFormat);
dateParser.set2DigitYearStart(localStartDate);
final ParsePosition pos = new ParsePosition(0);
final Date result = dateParser.parse(v, pos);
if (pos.getIndex() != 0) {
return result;
}
}
return null;
}
/**
* 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(final 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(final Date date, final String pattern) {
Args.notNull(date, "Date");
Args.notNull(pattern, "Pattern");
final SimpleDateFormat formatter = DateFormatHolder.formatFor(pattern);
return formatter.format(date);
}
/**
* Clears thread-local variable containing {@link java.text.DateFormat} cache.
*
* @since 4.3
*/
public static void clearThreadLocal() {
DateFormatHolder.clearThreadLocal();
}
/** 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}.
*
*/
final static class DateFormatHolder {
private static final ThreadLocal>>
THREADLOCAL_FORMATS = new ThreadLocal>>() {
@Override
protected SoftReference> initialValue() {
return new SoftReference>(
new HashMap());
}
};
/**
* creates a {@link SimpleDateFormat} for the requested format string.
*
* @param pattern
* a non-null format String according to
* {@link SimpleDateFormat}. The format is not checked against
* null 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(final String pattern) {
final SoftReference> ref = THREADLOCAL_FORMATS.get();
Map formats = ref.get();
if (formats == null) {
formats = new HashMap();
THREADLOCAL_FORMATS.set(
new SoftReference>(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;
}
public static void clearThreadLocal() {
THREADLOCAL_FORMATS.remove();
}
}
}