com.rometools.rome.io.impl.DateParser Maven / Gradle / Ivy
/*
* Copyright 2004 Sun Microsystems, Inc.
*
* 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 com.rometools.rome.io.impl;
import java.text.DateFormat;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.TimeZone;
/**
* A helper class that parses Dates out of Strings with date time in RFC822 and W3CDateTime formats
* plus the variants Atom (0.3) and RSS (0.9, 0.91, 0.92, 0.93, 0.94, 1.0 and 2.0) specificators
* added to those formats.
*
* It uses the JDK java.text.SimpleDateFormat class attemtping the parse using a mask for each one
* of the possible formats.
*
*/
public class DateParser {
private static String[] ADDITIONAL_MASKS;
// order is like this because the SimpleDateFormat.parse does not fail with exception if it can
// parse a valid date out of a substring of the full string given the mask so we have to check
// the most complete format first, then it fails with exception
private static final String[] RFC822_MASKS = { "EEE, dd MMM yy HH:mm:ss z", "EEE, dd MMM yy HH:mm z", "dd MMM yy HH:mm:ss z", "dd MMM yy HH:mm z" };
// order is like this because the SimpleDateFormat.parse does not fail with exception if it can
// parse a valid date out of a substring of the full string given the mask so we have to check
// the most complete format first, then it fails with exception
private static final String[] W3CDATETIME_MASKS = { "yyyy-MM-dd'T'HH:mm:ss.SSSz", "yyyy-MM-dd't'HH:mm:ss.SSSz", "yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
"yyyy-MM-dd't'HH:mm:ss.SSS'z'", "yyyy-MM-dd'T'HH:mm:ssz", "yyyy-MM-dd't'HH:mm:ssz", "yyyy-MM-dd'T'HH:mm:ssZ", "yyyy-MM-dd't'HH:mm:ssZ",
"yyyy-MM-dd'T'HH:mm:ss'Z'", "yyyy-MM-dd't'HH:mm:ss'z'", "yyyy-MM-dd'T'HH:mmz", // together
// with
// logic
// in
// the
// parseW3CDateTime
// they
"yyyy-MM'T'HH:mmz", // handle W3C dates without time forcing them to
// be GMT
"yyyy'T'HH:mmz", "yyyy-MM-dd't'HH:mmz", "yyyy-MM-dd'T'HH:mm'Z'", "yyyy-MM-dd't'HH:mm'z'", "yyyy-MM-dd", "yyyy-MM", "yyyy" };
/**
* The masks used to validate and parse the input to this Atom date. These are a lot more
* forgiving than what the Atom spec allows. The forms that are invalid according to the spec
* are indicated.
*/
@SuppressWarnings("unused")
private static final String[] masks = { "yyyy-MM-dd'T'HH:mm:ss.SSSz", "yyyy-MM-dd't'HH:mm:ss.SSSz", // invalid
"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'", "yyyy-MM-dd't'HH:mm:ss.SSS'z'", // invalid
"yyyy-MM-dd'T'HH:mm:ssz", "yyyy-MM-dd't'HH:mm:ssz", // invalid
"yyyy-MM-dd'T'HH:mm:ss'Z'", "yyyy-MM-dd't'HH:mm:ss'z'", // invalid
"yyyy-MM-dd'T'HH:mmz", // invalid
"yyyy-MM-dd't'HH:mmz", // invalid
"yyyy-MM-dd'T'HH:mm'Z'", // invalid
"yyyy-MM-dd't'HH:mm'z'", // invalid
"yyyy-MM-dd", "yyyy-MM", "yyyy" };
static {
ADDITIONAL_MASKS = PropertiesLoader.getPropertiesLoader().getTokenizedProperty("datetime.extra.masks", "|");
}
/**
* Private constructor to avoid DateParser instances creation.
*/
private DateParser() {
}
/**
* Parses a Date out of a string using an array of masks.
*
* It uses the masks in order until one of them succedes or all fail.
*
*
* @param masks array of masks to use for parsing the string
* @param sDate string to parse for a date.
* @return the Date represented by the given string using one of the given masks. It returns
* null if it was not possible to parse the the string with any of the masks.
*
*/
private static Date parseUsingMask(final String[] masks, String sDate, final Locale locale) {
if (sDate != null) {
sDate = sDate.trim();
}
ParsePosition pp = null;
Date d = null;
for (int i = 0; d == null && i < masks.length; i++) {
final DateFormat df = new SimpleDateFormat(masks[i].trim(), locale);
// df.setLenient(false);
df.setLenient(true);
try {
pp = new ParsePosition(0);
d = df.parse(sDate, pp);
if (pp.getIndex() != sDate.length()) {
d = null;
}
} catch (final Exception ex1) {
}
}
return d;
}
/**
* Parses a Date out of a String with a date in RFC822 format.
*
* It parsers the following formats:
*
* - "EEE, dd MMM yyyy HH:mm:ss z"
* - "EEE, dd MMM yyyy HH:mm z"
* - "EEE, dd MMM yy HH:mm:ss z"
* - "EEE, dd MMM yy HH:mm z"
* - "dd MMM yyyy HH:mm:ss z"
* - "dd MMM yyyy HH:mm z"
* - "dd MMM yy HH:mm:ss z"
* - "dd MMM yy HH:mm z"
*
*
* Refer to the java.text.SimpleDateFormat javadocs for details on the format of each element.
*
*
* @param sDate string to parse for a date.
* @return the Date represented by the given RFC822 string. It returns null if it was not
* possible to parse the given string into a Date.
*
*/
public static Date parseRFC822(String sDate, final Locale locale) {
sDate = convertUnsupportedTimeZones(sDate);
return parseUsingMask(RFC822_MASKS, sDate, locale);
}
private static String convertUnsupportedTimeZones(String sDate) {
final List unsupportedZeroOffsetTimeZones = Arrays.asList("UT", "Z");
for (String timeZone : unsupportedZeroOffsetTimeZones) {
if (sDate.endsWith(timeZone)) {
return replaceLastOccurrence(sDate, timeZone, "UTC");
}
}
return sDate;
}
private static String replaceLastOccurrence(String original, String target, String replacement) {
final int lastIndexOfTarget = original.lastIndexOf(target);
if (lastIndexOfTarget == -1) {
return original;
} else {
return new StringBuilder(original)
.replace(lastIndexOfTarget, lastIndexOfTarget + target.length(), replacement)
.toString();
}
}
/**
* Parses a Date out of a String with a date in W3C date-time format.
*
* It parsers the following formats:
*
* - "yyyy-MM-dd'T'HH:mm:ssz"
* - "yyyy-MM-dd'T'HH:mmz"
* - "yyyy-MM-dd"
* - "yyyy-MM"
* - "yyyy"
*
*
* Refer to the java.text.SimpleDateFormat javadocs for details on the format of each element.
*
*
* @param sDate string to parse for a date.
* @return the Date represented by the given W3C date-time string. It returns null if it
* was not possible to parse the given string into a Date.
*
*/
public static Date parseW3CDateTime(String sDate, final Locale locale) {
// if sDate has time on it, it injects 'GTM' before de TZ displacement to allow the
// SimpleDateFormat parser to parse it properly
final int tIndex = sDate.indexOf("T");
if (tIndex > -1) {
if (sDate.endsWith("Z")) {
sDate = sDate.substring(0, sDate.length() - 1) + "+00:00";
}
int tzdIndex = sDate.indexOf("+", tIndex);
if (tzdIndex == -1) {
tzdIndex = sDate.indexOf("-", tIndex);
}
if (tzdIndex > -1) {
String pre = sDate.substring(0, tzdIndex);
final int secFraction = pre.indexOf(",");
if (secFraction > -1) {
pre = pre.substring(0, secFraction);
}
final String post = sDate.substring(tzdIndex);
sDate = pre + "GMT" + post;
}
} else {
sDate += "T00:00GMT";
}
return parseUsingMask(W3CDATETIME_MASKS, sDate, locale);
}
/**
* Parses a Date out of a String with a date in W3C date-time format or in a RFC822 format.
*
*
* @param sDate string to parse for a date.
* @return the Date represented by the given W3C date-time string. It returns null if it
* was not possible to parse the given string into a Date.
*
* */
public static Date parseDate(final String sDate, final Locale locale) {
Date date = null;
if (ADDITIONAL_MASKS.length > 0) {
date = parseUsingMask(ADDITIONAL_MASKS, sDate, locale);
if (date != null) {
return date;
}
}
date = parseW3CDateTime(sDate, locale);
if (date == null) {
date = parseRFC822(sDate, locale);
}
return date;
}
/**
* create a RFC822 representation of a date.
*
* Refer to the java.text.SimpleDateFormat javadocs for details on the format of each element.
*
*
* @param date Date to parse
* @return the RFC822 represented by the given Date It returns null if it was not
* possible to parse the date.
*
*/
public static String formatRFC822(final Date date, final Locale locale) {
final SimpleDateFormat dateFormater = new SimpleDateFormat("EEE, dd MMM yyyy HH:mm:ss 'GMT'", locale);
dateFormater.setTimeZone(TimeZone.getTimeZone("GMT"));
return dateFormater.format(date);
}
/**
* create a W3C Date Time representation of a date.
*
* Refer to the java.text.SimpleDateFormat javadocs for details on the format of each element.
*
*
* @param date Date to parse
* @return the W3C Date Time represented by the given Date It returns null if it was not
* possible to parse the date.
*
*/
public static String formatW3CDateTime(final Date date, final Locale locale) {
final SimpleDateFormat dateFormater = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'", locale);
dateFormater.setTimeZone(TimeZone.getTimeZone("GMT"));
return dateFormater.format(date);
}
}
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