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//revised from skaringa
import java.text.DateFormat;
import java.text.FieldPosition;
import java.text.ParsePosition;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
/**
* Format and parse an ISO 8601 DateTimeFormat used in XML documents.
* This lexical representation is the ISO 8601
* extended format CCYY-MM-DDThh:mm:ss
* where "CC" represents the century, "YY" the year, "MM" the month
* and "DD" the day,
* preceded by an optional leading "-" sign to indicate a negative number.
* If the sign is omitted, "+" is assumed.
* The letter "T" is the date/time separator
* and "hh", "mm", "ss" represent hour, minute and second respectively.
* This representation may be immediately followed by a "Z" to indicate
* Coordinated Universal Time (UTC) or, to indicate the time zone,
* i.e. the difference between the local time and Coordinated Universal Time,
* immediately followed by a sign, + or -,
* followed by the difference from UTC represented as hh:mm.
*
*/
public class ISO8601DateTimeFormat extends DateFormat {
/**
* Construct a new ISO8601DateTimeFormat using the default time zone.
*
*/
public ISO8601DateTimeFormat() {
setCalendar(Calendar.getInstance());
}
/**
* Construct a new ISO8601DateTimeFormat using a specific time zone.
* @param tz The time zone used to format and parse the date.
*/
public ISO8601DateTimeFormat(TimeZone tz) {
setCalendar(Calendar.getInstance(tz));
}
/**
* @see DateFormat#parse(String, ParsePosition)
*/
public Date parse(String text, ParsePosition pos) {
int i = pos.getIndex();
try {
int year = Integer.valueOf(text.substring(i, i + 4)).intValue();
i += 4;
if (text.charAt(i) != '-') {
throw new NumberFormatException();
}
i++;
int month = Integer.valueOf(text.substring(i, i + 2)).intValue() - 1;
i += 2;
if (text.charAt(i) != '-') {
throw new NumberFormatException();
}
i++;
int day = Integer.valueOf(text.substring(i, i + 2)).intValue();
i += 2;
if (text.charAt(i) != 'T') {
throw new NumberFormatException();
}
i++;
int hour = Integer.valueOf(text.substring(i, i + 2)).intValue();
i += 2;
if (text.charAt(i) != ':') {
throw new NumberFormatException();
}
i++;
int mins = Integer.valueOf(text.substring(i, i + 2)).intValue();
i += 2;
int secs = 0;
if (i < text.length() && text.charAt(i) == ':') {
// handle seconds flexible
i++;
secs = Integer.valueOf(text.substring(i, i + 2)).intValue();
i += 2;
}
calendar.set(year, month, day, hour, mins, secs);
calendar.set(Calendar.MILLISECOND, 0); // no parts of a second
i = parseTZ(i, text);
}
catch (NumberFormatException ex) {
pos.setErrorIndex(i);
return null;
}
catch (IndexOutOfBoundsException ex) {
pos.setErrorIndex(i);
return null;
}
finally {
pos.setIndex(i);
}
return calendar.getTime();
}
/**
* Parse the time zone.
* @param i The position to start parsing.
* @param text The text to parse.
* @return The position after parsing has finished.
*/
protected final int parseTZ(int i, String text) {
if (i < text.length()) {
// check and handle the zone/dst offset
int offset = 0;
if (text.charAt(i) == 'Z') {
offset = 0;
i++;
}
else {
int sign = 1;
if (text.charAt(i) == '-') {
sign = -1;
}
else if (text.charAt(i) != '+') {
throw new NumberFormatException();
}
i++;
int offsetHour = Integer.valueOf(text.substring(i, i + 2)).intValue();
i += 2;
if (text.charAt(i) != ':') {
throw new NumberFormatException();
}
i++;
int offsetMin = Integer.valueOf(text.substring(i, i + 2)).intValue();
i += 2;
offset = ((offsetHour * 60) + offsetMin) * 60000 * sign;
}
int offsetCal =
calendar.get(Calendar.ZONE_OFFSET) + calendar.get(Calendar.DST_OFFSET);
calendar.add(Calendar.MILLISECOND, offsetCal - offset);
}
return i;
}
/**
* @see DateFormat#format(Date, StringBuffer, FieldPosition)
*/
public StringBuffer format(
Date date,
StringBuffer sbuf,
FieldPosition fieldPosition) {
calendar.setTime(date);
writeCCYYMM(sbuf);
sbuf.append('T');
writehhmmss(sbuf);
writeTZ(sbuf);
return sbuf;
}
/**
* Write the time zone string.
* @param sbuf The buffer to append the time zone.
*/
protected final void writeTZ(StringBuffer sbuf) {
int offset =
calendar.get(Calendar.ZONE_OFFSET) + calendar.get(Calendar.DST_OFFSET);
if (offset == 0) {
sbuf.append('Z');
}
else {
int offsetHour = offset / 3600000;
int offsetMin = (offset % 3600000) / 60000;
if (offset >= 0) {
sbuf.append('+');
}
else {
sbuf.append('-');
offsetHour = 0 - offsetHour;
offsetMin = 0 - offsetMin;
}
appendInt(sbuf, offsetHour, 2);
sbuf.append(':');
appendInt(sbuf, offsetMin, 2);
}
}
/**
* Write hour, minutes, and seconds.
* @param sbuf The buffer to append the string.
*/
protected final void writehhmmss(StringBuffer sbuf) {
int hour = calendar.get(Calendar.HOUR_OF_DAY);
appendInt(sbuf, hour, 2);
sbuf.append(':');
int mins = calendar.get(Calendar.MINUTE);
appendInt(sbuf, mins, 2);
sbuf.append(':');
int secs = calendar.get(Calendar.SECOND);
appendInt(sbuf, secs, 2);
}
/**
* Write century, year, and months.
* @param sbuf The buffer to append the string.
*/
protected final void writeCCYYMM(StringBuffer sbuf) {
int year = calendar.get(Calendar.YEAR);
appendInt(sbuf, year, 4);
String month;
switch (calendar.get(Calendar.MONTH)) {
case Calendar.JANUARY :
month = "-01-";
break;
case Calendar.FEBRUARY :
month = "-02-";
break;
case Calendar.MARCH :
month = "-03-";
break;
case Calendar.APRIL :
month = "-04-";
break;
case Calendar.MAY :
month = "-05-";
break;
case Calendar.JUNE :
month = "-06-";
break;
case Calendar.JULY :
month = "-07-";
break;
case Calendar.AUGUST :
month = "-08-";
break;
case Calendar.SEPTEMBER :
month = "-09-";
break;
case Calendar.OCTOBER :
month = "-10-";
break;
case Calendar.NOVEMBER :
month = "-11-";
break;
case Calendar.DECEMBER :
month = "-12-";
break;
default :
month = "-NA-";
break;
}
sbuf.append(month);
int day = calendar.get(Calendar.DAY_OF_MONTH);
appendInt(sbuf, day, 2);
}
/**
* Write an integer value with leading zeros.
* @param buf The buffer to append the string.
* @param value The value to write.
* @param length The length of the string to write.
*/
protected final void appendInt(StringBuffer buf, int value, int length) {
int len1 = buf.length();
buf.append(value);
int len2 = buf.length();
for (int i = len2; i < len1 + length; ++i) {
buf.insert(len1, '0');
}
}
}
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