Date objects returned are not, but
* these objects are cloned before being returned.
*
* @since 1.0
* @author Marco Barreno
* @author Seth Proctor
* @author Steve Hanna
*/
public class DateAttribute extends AttributeValue
{
/**
* Official name of this type
*/
public static final String identifier =
"http://www.w3.org/2001/XMLSchema#date";
/**
* URI version of name for this type
* * This field is initialized by a static initializer so that * we can catch any exceptions thrown by URI(String) and * transform them into a RuntimeException, since this should * never happen but should be reported properly if it ever does. *
* This object is used for synchronization whenever we need * protection across this whole class. */ private static URI identifierURI; /** * RuntimeException that wraps an Exception thrown during the * creation of identifierURI, null if none. */ private static RuntimeException earlyException; /** * Static initializer that initializes the identifierURI * class field so that we can catch any exceptions thrown * by URI(String) and transform them into a RuntimeException. * Such exceptions should never happen but should be reported * properly if they ever do. */ static { try { identifierURI = new URI(identifier); } catch (Exception e) { earlyException = new IllegalArgumentException(); earlyException.initCause(e); } }; /** * Parser for dates with no time zones *
* This field is only initialized if needed (by initParsers()). *
* NOTE: This object should only be accessed from code that * has synchronized on it, since SimpleDateFormat objects are not * thread-safe. If this is causing performance problems, we could * easily make this a method variable in methods that use it * instead of a class field. But that would mean we'd need to * spend a lot more time creating these objects. */ private static DateFormat simpleParser; /** * Parser for dates with RFC 822 time zones (like +0300) *
* This field is only initialized if needed (by initParsers()). *
* NOTE: This object should only be accessed from code that * has a lock on it, since SimpleDateFormat objects are not * thread-safe. */ private static DateFormat zoneParser; /** * Calendar for GMT *
* NOTE: This object should only be accessed from code that
* has a lock on it, since Calendar objects are not generally
* thread-safe.
*/
private static Calendar gmtCalendar;
/**
* Number of nanoseconds per millisecond
* (shared by other classes in this package)
*/
static final int NANOS_PER_MILLI = 1000000;
/**
* Number of milliseconds per second
* (shared by other classes in this package)
*/
static final int MILLIS_PER_SECOND = 1000;
/**
* Number of seconds in a minute
* (shared by other classes in this package)
*/
static final int SECONDS_PER_MINUTE = 60;
/**
* Number of minutes in an hour
* (shared by other classes in this package)
*/
static final int MINUTES_PER_HOUR = 60;
/**
* Number of hours in a day
* (shared by other classes in this package)
*/
static final int HOURS_PER_DAY = 24;
/**
* Number of nanoseconds per second
* (shared by other classes in this package)
*/
static final int NANOS_PER_SECOND = NANOS_PER_MILLI * MILLIS_PER_SECOND;
/**
* Number of milliseconds in a minute
* (shared by other classes in this package)
*/
static final int MILLIS_PER_MINUTE =
MILLIS_PER_SECOND * SECONDS_PER_MINUTE;
/**
* Number of milliseconds in an hour
* (shared by other classes in this package)
*/
static final int MILLIS_PER_HOUR =
MILLIS_PER_MINUTE * MINUTES_PER_HOUR;
/**
* Number of milliseconds in a day
* (shared by other classes in this package)
*/
static final long MILLIS_PER_DAY = MILLIS_PER_HOUR * HOURS_PER_DAY;
/**
* Time zone value that indicates that the time zone was not
* specified.
*/
public static final int TZ_UNSPECIFIED = -1000000;
/**
* The instant (in GMT) at which the specified date began (midnight)
* in the specified time zone. If no time zone was specified,
* the local time zone is used.
*/
private Date value;
/**
* The time zone specified for this object (or TZ_UNSPECIFIED if
* unspecified). The offset to GMT, in minutes.
*/
private int timeZone;
/**
* The time zone actually used for this object (if it was
* originally unspecified, the default time zone used).
* The offset to GMT, in minutes.
*/
private int defaultedTimeZone;
/**
* Cached encoded value (null if not cached yet).
*/
private String encodedValue = null;
/**
* Creates a new TimeAttribute that represents
* the current date in the default time zone.
*/
public DateAttribute() {
super(identifierURI);
// Get the current time and GMT offset
Date currDate = new Date();
int currOffset = DateTimeAttribute.getDefaultTZOffset(currDate);
long millis = currDate.getTime();
// Now find out the last time it was midnight local time
// (actually the last time it was midnight with the current
// GMT offset, but that's good enough).
// Skip back by time zone offset.
millis += currOffset * MILLIS_PER_MINUTE;
// Reset to last GMT midnight
millis -= millis % MILLIS_PER_DAY;
// Skip forward by time zone offset.
millis -= currOffset * MILLIS_PER_MINUTE;
currDate.setTime(millis);
init(currDate, currOffset, currOffset);
}
/**
* Creates a new DateAttribute that represents
* the date supplied.
*
* @param date a Date object representing the
* instant at which the specified date began (midnight)
* in the specified time zone
* @param timeZone the time zone specified for this object
* (or TZ_UNSPECIFIED if unspecified). The
* offset to GMT, in minutes.
* @param defaultedTimeZone the time zone actually used for this
* object (if it was originally unspecified,
* the default time zone used).
* The offset to GMT, in minutes.
*/
public DateAttribute(Date date, int timeZone, int defaultedTimeZone) {
super(identifierURI);
init(date, timeZone, defaultedTimeZone);
}
/**
* Initialization code shared by constructors.
*
* @param date a Date object representing the
* instant at which the specified date began (midnight)
* in the specified time zone.
* @param timeZone the time zone specified for this object
* (or TZ_UNSPECIFIED if unspecified). The
* offset to GMT, in minutes.
* @param defaultedTimeZone the time zone actually used for this
* object (if it was originally unspecified,
* the default time zone used).
* The offset to GMT, in minutes.
*/
private void init(Date date, int timeZone, int defaultedTimeZone) {
// Shouldn't happen, but just in case...
if (earlyException != null)
throw earlyException;
this.value = (Date) date.clone();
this.timeZone = timeZone;
this.defaultedTimeZone = defaultedTimeZone;
}
/**
* Returns a new DateAttribute that represents
* the xs:date at a particular DOM node.
*
* @param root the Node that contains the desired value
* @return a new DateAttribute representing the
* appropriate value (null if there is a parsing error)
*/
public static DateAttribute getInstance(Node root)
throws ParseException
{
return getInstance(root.getFirstChild().getNodeValue());
}
/**
* Returns a new DateAttribute that represents
* the xs:date value indicated by the string provided.
*
* @param value a string representing the desired value
* @return a new DateAttribute representing the
* desired value (null if there is a parsing error)
*/
public static DateAttribute getInstance(String value)
throws ParseException
{
Date dateValue = null;
int timeZone;
int defaultedTimeZone;
if (simpleParser == null)
initParsers();
// If string ends with Z, it's in GMT. Chop off the Z and
// add +0000 to make the time zone explicit, then parse it
// with the timezone parser.
if (value.endsWith("Z")) {
value = value.substring(0, value.length()-1) + "+0000";
dateValue = strictParse(zoneParser, value);
timeZone = 0;
defaultedTimeZone = 0;
} else {
// If string ends with :XX, it must have a time zone
// or be invalid. Strip off the possible time zone and
// make sure what's left is a valid simple date. If so,
// reformat the time zone by stripping out the colon
// and parse the whole thing with the timezone parser.
int len = value.length();
if ((len > 6) && (value.charAt(len-3) == ':')) {
Date gmtValue = strictParse(zoneParser,
value.substring(0,len-6) +
"+0000");
value = value.substring(0, len-3) +
value.substring(len-2, len);
dateValue = strictParse(zoneParser, value);
timeZone =
(int) (gmtValue.getTime() - dateValue.getTime());
timeZone = timeZone / 60000;
defaultedTimeZone = timeZone;
} else {
// No funny business. This must be a simple date.
dateValue = strictParse(simpleParser, value);
timeZone = TZ_UNSPECIFIED;
Date gmtValue = strictParse(zoneParser, value + "+0000");
defaultedTimeZone =
(int) (gmtValue.getTime() - dateValue.getTime());
defaultedTimeZone = defaultedTimeZone / 60000;
}
}
// If parsing went OK, create a new DateAttribute object and
// return it.
DateAttribute attr = new DateAttribute(dateValue, timeZone,
defaultedTimeZone);
return attr;
}
/**
* Parse a String using a DateFormat parser, requiring that
* the entire String be consumed by the parser. On success,
* return a Date. On failure, throw a ParseException.
*
* Synchronize on the parser object when using it, since we
* assume they're the shared static objects in this class.
*/
private static Date strictParse(DateFormat parser, String str)
throws ParseException {
ParsePosition pos = new ParsePosition(0);
Date ret;
synchronized (parser) {
ret = parser.parse(str, pos);
}
if (pos.getIndex() != str.length())
throw new ParseException("", 0);
return ret;
}
/**
* Initialize the parser objects.
*/
private static void initParsers() {
// If simpleParser is already set, we're done.
if (simpleParser != null)
return;
// Make sure that identifierURI is not null
if (earlyException != null)
throw earlyException;
// Synchronize on identifierURI while initializing parsers
// so we don't end up using a half-way initialized parser
synchronized (identifierURI) {
// This simple parser has no time zone
simpleParser = new SimpleDateFormat("yyyy-MM-dd");
simpleParser.setLenient(false);
// This parser has a four digit offset to GMT with sign
zoneParser = new SimpleDateFormat("yyyy-MM-ddZ");
zoneParser.setLenient(false);
}
}
/**
* Gets the date represented by this object. The return value is
* a Date object representing the
* instant at which the specified date began (midnight)
* in the time zone.
*
* NOTE: The Date object is cloned before it
* is returned to avoid unauthorized changes.
*
* @return a Date object representing the instant
* at which the date began
*/
public Date getValue() {
return (Date) value.clone();
}
/**
* Gets the specified time zone of this object (or
* TZ_UNSPECIFIED if unspecified).
*
* @return the offset to GMT in minutes (positive or negative)
*/
public int getTimeZone() {
return timeZone;
}
/**
* Gets the time zone actually used for this object (if it was
* originally unspecified, the default time zone used).
*
* @return the offset to GMT in minutes (positive or negative)
*/
public int getDefaultedTimeZone() {
return defaultedTimeZone;
}
/**
* Returns true if the input is an instance of this class and if its
* value equals the value contained in this class.
*
* Two DateAttributes are equal if and only if the
* instant on which the date began is equal. This means that they
* must have the same time zone.
*
* @param o the object to compare
*
* @return true if this object and the input represent the same value
*/
public boolean equals(Object o) {
if (! (o instanceof DateAttribute))
return false;
DateAttribute other = (DateAttribute)o;
return value.equals(other.value);
}
/**
* Returns the hashcode value used to index and compare this object with
* others of the same type.
*
* @return the object's hashcode value
*/
public int hashCode() {
// Only the value field is considered by the equals method, so only
// that field should be considered by this method.
return value.hashCode();
}
/**
* Converts to a String representation.
*
* @return the String representation
*/
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("DateAttribute: [\n");
sb.append(" Date: " + value + " local time");
sb.append(" TimeZone: " + timeZone);
sb.append(" Defaulted TimeZone: " + defaultedTimeZone);
sb.append("]");
return sb.toString();
}
/**
* Encodes the value in a form suitable for including in XML data like
* a request or an obligation. This must return a value that could in
* turn be used by the factory to create a new instance with the same
* value.
*
* @return a String form of the value
*/
public String encode() {
if (encodedValue != null)
return encodedValue;
if (timeZone == TZ_UNSPECIFIED) {
// If no time zone was specified, format Date value in
// local time with no time zone string.
initParsers();
synchronized (simpleParser) {
encodedValue = simpleParser.format(value);
}
} else {
// If a time zone was specified, don't use SimpleParser
// because it can only format dates in the local (default)
// time zone. And the offset between that time zone and the
// time zone we need to display can vary in complicated ways.
// Instead, do it ourselves using our formatDateWithTZ method.
encodedValue = formatDateWithTZ();
}
return encodedValue;
}
/**
* Encodes the value of this object as an xsi:date.
* Only for use when the time zone is specified.
*
* @return a String form of the value
*/
private String formatDateWithTZ() {
if (gmtCalendar == null) {
TimeZone gmtTimeZone = TimeZone.getTimeZone("GMT");
// Locale doesn't make much difference here. We don't use
// any of the strings in the Locale and we don't do anything
// that depends on week count conventions. We use the US
// locale because it's always around and it ensures that we
// will always get a Gregorian calendar, which is necessary
// for compliance with ISO 8501.
gmtCalendar = Calendar.getInstance(gmtTimeZone, Locale.US);
}
// "YYYY-MM-DD+hh:mm".length() = 16
// Length may be longer if years < -999 or > 9999
StringBuffer buf = new StringBuffer(16);
synchronized (gmtCalendar) {
// Start with the GMT instant when the date started in the
// specified time zone (would be 7:00 PM the preceding day
// if the specified time zone was +0500).
gmtCalendar.setTime(value);
// Bump by the timeZone (so we get the right date/time that
// that we want to format)
gmtCalendar.add(Calendar.MINUTE, timeZone);
// Now, assemble the string
int year = gmtCalendar.get(Calendar.YEAR);
buf.append(zeroPadInt(year, 4));
buf.append('-');
// JANUARY is 0
int month = gmtCalendar.get(Calendar.MONTH) + 1;
buf.append(zeroPadInt(month, 2));
buf.append('-');
int dom = gmtCalendar.get(Calendar.DAY_OF_MONTH);
buf.append(zeroPadInt(dom, 2));
}
int tzNoSign = timeZone;
if (timeZone < 0) {
tzNoSign = -tzNoSign;
buf.append('-');
} else
buf.append('+');
int tzHours = tzNoSign / 60;
buf.append(zeroPadInt(tzHours, 2));
buf.append(':');
int tzMinutes = tzNoSign % 60;
buf.append(zeroPadInt(tzMinutes, 2));
return buf.toString();
}
/**
* Takes a String representation of an integer (an optional
* sign followed by digits) and pads it with zeros on the left
* until it has at least the specified number of digits.
* Note that this function will work for an integer of
* any size: int, long, etc.
*
* @param unpadded the unpadded String
* (must have length of at least one)
* @param minDigits the minimum number of digits desired
* @return the padded String
*/
static String zeroPadIntString(String unpadded, int minDigits) {
int len = unpadded.length();
// Get the sign character (or 0 if none)
char sign = unpadded.charAt(0);
if ((sign != '-') && (sign != '+'))
sign = 0;
// The number of characters required is the number of digits,
// plus one for the sign if present.
int minChars = minDigits;
if (sign != 0)
minChars++;
// If we already have that many characters, we're done.
if (len >= minChars)
return unpadded;
// Otherwise, create the buffer
StringBuffer buf = new StringBuffer();
// Copy in the sign first, if present
if (sign != 0) {
buf.append(sign);
}
// Add the zeros
int zerosNeeded = minChars - len;
while (zerosNeeded-- != 0)
buf.append('0');
// Copy the rest of the unpadded string
if (sign != 0) {
// Skip sign
buf.append(unpadded.substring(1, len));
} else {
buf.append(unpadded);
}
return buf.toString();
}
/**
* Converts an integer to a base 10 string and pads it with
* zeros on the left until it has at least the specified
* number of digits. Note that the length of the resulting
* string will be greater than minDigits if the number is
* negative since the string will start with a minus sign.
*
* @param intValue the integer to convert
* @param minDigits the minimum number of digits desired
* @return the padded String
*/
static String zeroPadInt(int intValue, int minDigits) {
return zeroPadIntString(Integer.toString(intValue), minDigits);
}
}