Date objects returned are not, but
* these objects are cloned before being returned.
*
* @since 1.0
* @author Steve Hanna
*/
public class YearMonthDurationAttribute extends AttributeValue
{
/**
* Official name of this type
*/
public static final String identifier =
"http://www.w3.org/TR/2002/WD-xquery-operators-20020816#" +
"yearMonthDuration";
/**
* 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.
*/
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);
}
};
/**
* Regular expression for yearMonthDuration (a la java.util.regex)
*/
private static final String patternString =
"(\\-)?P((\\d+)?Y)?((\\d+)?M)?";
/**
* The index of the capturing group for the negative sign.
*/
private static final int GROUP_SIGN = 1;
/**
* The index of the capturing group for the number of years.
*/
private static final int GROUP_YEARS = 3;
/**
* The index of the capturing group for the number of months.
*/
private static final int GROUP_MONTHS = 5;
/**
* Static BigInteger values. We only use these if one of
* the components is bigger than Integer.MAX_LONG and we
* want to detect overflow, so we don't initialize these
* until they're needed.
*/
private static BigInteger big12;
private static BigInteger bigMaxLong;
/**
* A shared Pattern object, only initialized if needed
*/
private static Pattern pattern;
/**
* Negative flag. true if duration is negative, false otherwise
*/
private boolean negative;
/**
* Number of years
*/
private long years;
/**
* Number of months
*/
private long months;
/**
* Total number of months (used for equals)
*/
private long totalMonths;
/**
* Cached encoded value (null if not cached yet).
*/
private String encodedValue = null;
/**
* Creates a new YearMonthDurationAttribute that represents
* the duration supplied.
*
* @param negative true if the duration is negative, false otherwise
* @param years the number of years in the duration (must be positive)
* @param months the number of months in the duration (must be positive)
* @throws IllegalArgumentException if the total number of months
* exceeds Long.MAX_LONG or the number
* of months or years is negative
*/
public YearMonthDurationAttribute(boolean negative, long years,
long months)
throws IllegalArgumentException {
super(identifierURI);
// Shouldn't happen, but just in case...
if (earlyException != null)
throw earlyException;
this.negative = negative;
this.years = years;
this.months = months;
// Convert all the components except nanoseconds to milliseconds
// If any of the components is big (too big to be an int),
// use the BigInteger class to do the math so we can detect
// overflow.
if ((years > Integer.MAX_VALUE) || (months > Integer.MAX_VALUE)) {
if (big12 == null) {
big12 = BigInteger.valueOf(12);
bigMaxLong = BigInteger.valueOf(Long.MAX_VALUE);
}
BigInteger bigMonths = BigInteger.valueOf(months);
BigInteger bigYears = BigInteger.valueOf(years);
BigInteger bigTotal = bigYears.multiply(big12).add(bigMonths);
// If the result is bigger than Long.MAX_VALUE, we have an
// overflow. Indicate an error (should be a processing error,
// since it can be argued that we should handle gigantic
// values for this).
if (bigTotal.compareTo(bigMaxLong) == 1)
throw new IllegalArgumentException("total number of " +
"months " +
"exceeds Long.MAX_VALUE");
// If no overflow, convert to a long.
totalMonths = bigTotal.longValue();
if (negative)
totalMonths = - totalMonths;
} else {
// The numbers are small, so do it the fast way.
totalMonths = ((years * 12) + months) * (negative ? -1 : 1);
}
}
/**
* Returns a new YearMonthDurationAttribute that represents
* the xf:yearMonthDuration at a particular DOM node.
*
* @param root the Node that contains the desired value
* @return a new YearMonthDurationAttribute representing the
* appropriate value
* @throws ParsingException if any problems occurred while parsing
*/
public static YearMonthDurationAttribute getInstance(Node root)
throws ParsingException
{
return getInstance(root.getFirstChild().getNodeValue());
}
/**
* Returns the long value for the capturing group groupNumber.
* This method takes a Matcher that has been used to match a
* Pattern against a String, fetches the value for the specified
* capturing group, converts that value to an long, and returns
* the value. If that group did not match, 0 is returned.
* If the matched value is not a valid long, NumberFormatException
* is thrown.
*
* @param matcher the Matcher from which to fetch the group
* @param groupNumber the group number to fetch
* @return the long value for that groupNumber
* @throws NumberFormatException if the string value for that
* groupNumber is not a valid long
*/
private static long parseGroup(Matcher matcher, int groupNumber)
throws NumberFormatException {
long groupLong = 0;
if (matcher.start(groupNumber) != -1) {
String groupString = matcher.group(groupNumber);
groupLong = Long.parseLong(groupString);
}
return groupLong;
}
/**
* Returns a new YearMonthDurationAttribute that represents
* the xf:yearMonthDuration value indicated by the string provided.
*
* @param value a string representing the desired value
*
* @return a new YearMonthDurationAttribute representing the
* desired value
*
* @throws ParsingException if any problems occurred while parsing
*/
public static YearMonthDurationAttribute getInstance(String value)
throws ParsingException
{
boolean negative = false;
long years = 0;
long months = 0;
// Compile the pattern, if not already done.
if (pattern == null) {
try {
pattern = Pattern.compile(patternString);
} catch (PatternSyntaxException e) {
// This should never happen
throw new ParsingException("unexpected pattern syntax error");
}
}
// See if the value matches the pattern.
Matcher matcher = pattern.matcher(value);
boolean matches = matcher.matches();
// If not, syntax error!
if (!matches) {
throw new ParsingException("Syntax error in yearMonthDuration");
}
// If the negative group matched, the value is negative.
if (matcher.start(GROUP_SIGN) != -1)
negative = true;
try {
// If the years group matched, parse that value.
years = parseGroup(matcher, GROUP_YEARS);
// If the months group matched, parse that value.
months = parseGroup(matcher, GROUP_MONTHS);
} catch (NumberFormatException e) {
// If we run into a number that's too big to be a long
// that's an error. Really, it's a processing error,
// since one can argue that we should handle that.
throw new ParsingException("Unable to handle number size");
}
// If parsing went OK, create a new YearMonthDurationAttribute
// object and return it.
return new YearMonthDurationAttribute(negative, years, months);
}
/**
* Returns true if the duration is negative.
*
* @return true if the duration is negative, false otherwise
*/
public boolean isNegative() {
return negative;
}
/**
* Gets the number of years.
*
* @return the number of years
*/
public long getYears() {
return years;
}
/**
* Gets the number of months.
*
* @return the number of months
*/
public long getMonths() {
return months;
}
/**
* Returns true if the input is an instance of this class and if its
* value equals the value contained in this class.
*
* @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 YearMonthDurationAttribute))
return false;
YearMonthDurationAttribute other = (YearMonthDurationAttribute)o;
return (totalMonths == other.totalMonths);
}
/**
* Returns the hashcode value used to index and compare this object with
* others of the same type. Typically this is the hashcode of the backing
* data object.
*
* @return the object's hashcode value
*/
public int hashCode() {
return (int) totalMonths ^ (int) (totalMonths >> 32);
}
/**
* Converts to a String representation.
*
* @return the String representation
*/
public String toString() {
StringBuffer sb = new StringBuffer();
sb.append("YearMonthDurationAttribute: [\n");
sb.append(" Negative: " + negative);
sb.append(" Years: " + years);
sb.append(" Months: " + months);
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;
// Length is variable
StringBuffer buf = new StringBuffer(10);
if (negative)
buf.append('-');
buf.append('P');
if ((years != 0) || (months == 0)) {
buf.append(Long.toString(years));
buf.append('Y');
}
if (months != 0) {
buf.append(Long.toString(months));
buf.append('M');
}
encodedValue = buf.toString();
return encodedValue;
}
}