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.ParseException;
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.getInteger("org.apache.tomcat.util.http.FastHttpDateFormat.CACHE_SIZE", 1000).intValue();
// HTTP date formats
private static final String DATE_RFC5322 = "EEE, dd MMM yyyy HH:mm:ss z";
private static final String DATE_OBSOLETE_RFC850 = "EEEEEE, dd-MMM-yy HH:mm:ss zzz";
private static final String DATE_OBSOLETE_ASCTIME = "EEE MMMM d HH:mm:ss yyyy";
private static final ConcurrentDateFormat FORMAT_RFC5322;
private static final ConcurrentDateFormat FORMAT_OBSOLETE_RFC850;
private static final ConcurrentDateFormat FORMAT_OBSOLETE_ASCTIME;
private static final ConcurrentDateFormat[] httpParseFormats;
static {
// All the formats that use a timezone use GMT
TimeZone tz = TimeZone.getTimeZone("GMT");
FORMAT_RFC5322 = new ConcurrentDateFormat(DATE_RFC5322, Locale.US, tz);
FORMAT_OBSOLETE_RFC850 = new ConcurrentDateFormat(DATE_OBSOLETE_RFC850, Locale.US, tz);
FORMAT_OBSOLETE_ASCTIME = new ConcurrentDateFormat(DATE_OBSOLETE_ASCTIME, Locale.US, tz);
httpParseFormats =
new ConcurrentDateFormat[] { FORMAT_RFC5322, FORMAT_OBSOLETE_RFC850, FORMAT_OBSOLETE_ASCTIME };
}
/**
* 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 String getCurrentDate() {
long now = System.currentTimeMillis();
// Handle case where time moves backwards (e.g. system time corrected)
if (Math.abs(now - currentDateGenerated) > 1000) {
currentDate = FORMAT_RFC5322.format(new Date(now));
currentDateGenerated = now;
}
return currentDate;
}
/**
* Get the HTTP format of the specified date.
*
* @param value The date
*
* @return the HTTP date
*/
public static String formatDate(long value) {
Long longValue = Long.valueOf(value);
String cachedDate = formatCache.get(longValue);
if (cachedDate != null) {
return cachedDate;
}
String newDate = FORMAT_RFC5322.format(new Date(value));
updateFormatCache(longValue, newDate);
return newDate;
}
/**
* Try to parse the given date as an HTTP date.
*
* @param value The HTTP date
*
* @return the date as a long or -1 if the value cannot be parsed
*/
public static long parseDate(String value) {
Long cachedDate = parseCache.get(value);
if (cachedDate != null) {
return cachedDate.longValue();
}
long date = -1;
for (int i = 0; (date == -1) && (i < httpParseFormats.length); i++) {
try {
date = httpParseFormats[i].parse(value).getTime();
updateParseCache(value, Long.valueOf(date));
} catch (ParseException e) {
// Ignore
}
}
return date;
}
/**
* 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);
}
}