org.apache.tomcat.util.http.FastHttpDateFormat Maven / Gradle / Ivy
/*
* 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.
*/
package org.apache.tomcat.util.http;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.Map;
import java.util.TimeZone;
import java.util.concurrent.ConcurrentHashMap;
/**
* Utility class to generate HTTP dates.
*
* @author Remy Maucherat
*/
public final class FastHttpDateFormat {
// -------------------------------------------------------------- Variables
private static final int CACHE_SIZE =
Integer.parseInt(System.getProperty("org.apache.tomcat.util.http.FastHttpDateFormat.CACHE_SIZE", "1000"));
/**
* The only date format permitted when generating HTTP headers.
*/
public static final String RFC1123_DATE =
"EEE, dd MMM yyyy HH:mm:ss zzz";
private static final SimpleDateFormat format =
new SimpleDateFormat(RFC1123_DATE, Locale.US);
private static final TimeZone gmtZone = TimeZone.getTimeZone("GMT");
/**
* GMT timezone - all HTTP dates are on GMT
*/
static {
format.setTimeZone(gmtZone);
}
/**
* Instant on which the currentDate object was generated.
*/
private static volatile long currentDateGenerated = 0L;
/**
* Current formatted date.
*/
private static String currentDate = null;
/**
* Formatter cache.
*/
private static final Map formatCache = new ConcurrentHashMap<>(CACHE_SIZE);
/**
* Parser cache.
*/
private static final Map parseCache = new ConcurrentHashMap<>(CACHE_SIZE);
// --------------------------------------------------------- Public Methods
/**
* Get the current date in HTTP format.
* @return the HTTP date
*/
public static final String getCurrentDate() {
long now = System.currentTimeMillis();
if ((now - currentDateGenerated) > 1000) {
synchronized (format) {
if ((now - currentDateGenerated) > 1000) {
currentDate = format.format(new Date(now));
currentDateGenerated = now;
}
}
}
return currentDate;
}
/**
* Get the HTTP format of the specified date.
* @param value The date
* @param threadLocalformat Local format to avoid synchronization
* @return the HTTP date
*/
public static final String formatDate
(long value, DateFormat threadLocalformat) {
Long longValue = Long.valueOf(value);
String cachedDate = formatCache.get(longValue);
if (cachedDate != null) {
return cachedDate;
}
String newDate = null;
Date dateValue = new Date(value);
if (threadLocalformat != null) {
newDate = threadLocalformat.format(dateValue);
updateFormatCache(longValue, newDate);
} else {
synchronized (format) {
newDate = format.format(dateValue);
}
updateFormatCache(longValue, newDate);
}
return newDate;
}
/**
* Try to parse the given date as a HTTP date.
* @param value The HTTP date
* @param threadLocalformats Local format to avoid synchronization
* @return the date as a long
*/
public static final long parseDate(String value,
DateFormat[] threadLocalformats) {
Long cachedDate = parseCache.get(value);
if (cachedDate != null) {
return cachedDate.longValue();
}
Long date = null;
if (threadLocalformats != null) {
date = internalParseDate(value, threadLocalformats);
updateParseCache(value, date);
} else {
throw new IllegalArgumentException();
}
if (date == null) {
return (-1L);
}
return date.longValue();
}
/**
* Parse date with given formatters.
*/
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) {
// Ignore
}
}
if (date == null) {
return null;
}
return Long.valueOf(date.getTime());
}
/**
* Update cache.
*/
private static void updateFormatCache(Long key, String value) {
if (value == null) {
return;
}
if (formatCache.size() > CACHE_SIZE) {
formatCache.clear();
}
formatCache.put(key, value);
}
/**
* Update cache.
*/
private static void updateParseCache(String key, Long value) {
if (value == null) {
return;
}
if (parseCache.size() > CACHE_SIZE) {
parseCache.clear();
}
parseCache.put(key, value);
}
}