org.acegisecurity.ui.savedrequest.FastHttpDateFormat Maven / Gradle / Ivy
/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
*
* Licensed 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.
*/
package org.acegisecurity.ui.savedrequest;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Locale;
import java.util.TimeZone;
/**
* Utility class to generate HTTP dates.
* This class is based on code in Apache Tomcat.
*
* @author Remy Maucherat
* @author Andrey Grebnev
* @version $Id: FastHttpDateFormat.java 1496 2006-05-23 13:38:33Z benalex $
*/
public class FastHttpDateFormat {
//~ Static fields/initializers =====================================================================================
/** HTTP date format. */
protected static final SimpleDateFormat format = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US);
/** The set of SimpleDateFormat formats to use in getDateHeader()
. */
protected static final SimpleDateFormat[] formats = {
new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss zzz", Locale.US),
new SimpleDateFormat("EEEEEE, dd-MMM-yy HH:mm:ss zzz", Locale.US),
new SimpleDateFormat("EEE MMMM d HH:mm:ss yyyy", Locale.US)
};
/** GMT timezone - all HTTP dates are on GMT */
protected final static TimeZone gmtZone = TimeZone.getTimeZone("GMT");
static {
format.setTimeZone(gmtZone);
formats[0].setTimeZone(gmtZone);
formats[1].setTimeZone(gmtZone);
formats[2].setTimeZone(gmtZone);
}
/** Instant on which the currentDate object was generated. */
protected static long currentDateGenerated = 0L;
/** Current formatted date. */
protected static String currentDate = null;
/** Formatter cache. */
protected static final HashMap formatCache = new HashMap();
/** Parser cache. */
protected static final HashMap parseCache = new HashMap();
//~ Methods ========================================================================================================
/**
* Formats a specified date to HTTP format. If local format is not null
, it's used instead.
*
* @param value Date value to format
* @param threadLocalformat The format to use (or null
-- then HTTP format will be used)
*
* @return Formatted date
*/
public static final String formatDate(long value, DateFormat threadLocalformat) {
String cachedDate = null;
Long longValue = new Long(value);
try {
cachedDate = (String) formatCache.get(longValue);
} catch (Exception e) {}
if (cachedDate != null) {
return cachedDate;
}
String newDate = null;
Date dateValue = new Date(value);
if (threadLocalformat != null) {
newDate = threadLocalformat.format(dateValue);
synchronized (formatCache) {
updateCache(formatCache, longValue, newDate);
}
} else {
synchronized (formatCache) {
newDate = format.format(dateValue);
updateCache(formatCache, longValue, newDate);
}
}
return newDate;
}
/**
* Gets the current date in HTTP format.
*
* @return Current date in HTTP format
*/
public static final String getCurrentDate() {
long now = System.currentTimeMillis();
if ((now - currentDateGenerated) > 1000) {
synchronized (format) {
if ((now - currentDateGenerated) > 1000) {
currentDateGenerated = now;
currentDate = format.format(new Date(now));
}
}
}
return currentDate;
}
/**
* Parses date with given formatters.
*
* @param value The string to parse
* @param formats Array of formats to use
*
* @return Parsed date (or null
if no formatter mached)
*/
private static final Long internalParseDate(String value, DateFormat[] formats) {
Date date = null;
for (int i = 0; (date == null) && (i < formats.length); i++) {
try {
date = formats[i].parse(value);
} catch (ParseException e) {
;
}
}
if (date == null) {
return null;
}
return new Long(date.getTime());
}
/**
* Tries to parse the given date as an HTTP date. If local format list is not null
, it's used
* instead.
*
* @param value The string to parse
* @param threadLocalformats Array of formats to use for parsing. If null
, HTTP formats are used.
*
* @return Parsed date (or -1 if error occured)
*/
public static final long parseDate(String value, DateFormat[] threadLocalformats) {
Long cachedDate = null;
try {
cachedDate = (Long) parseCache.get(value);
} catch (Exception e) {}
if (cachedDate != null) {
return cachedDate.longValue();
}
Long date = null;
if (threadLocalformats != null) {
date = internalParseDate(value, threadLocalformats);
synchronized (parseCache) {
updateCache(parseCache, value, date);
}
} else {
synchronized (parseCache) {
date = internalParseDate(value, formats);
updateCache(parseCache, value, date);
}
}
if (date == null) {
return (-1L);
} else {
return date.longValue();
}
}
/**
* Updates cache.
*
* @param cache Cache to be updated
* @param key Key to be updated
* @param value New value
*/
private static final void updateCache(HashMap cache, Object key, Object value) {
if (value == null) {
return;
}
if (cache.size() > 1000) {
cache.clear();
}
cache.put(key, value);
}
}
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