plugins/org.eclipse.bpel.ui/src/org/eclipse/bpel/ui/util/BPELDateTimeHelpers.java - bpel/org.eclipse.bpel - Git at Google

 /*******************************************************************************
  * Copyright (c) 2005, 2012 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.bpel.ui.util;

 import java.util.Calendar;
 import java.util.GregorianCalendar;
 import java.util.TimeZone;

 import org.eclipse.bpel.ui.properties.DateTimeSelector;


 /**
  * Helpers for interacting with DateTimeSelector and DurationSelector widgets, and
  * serializing their values to XPath.
  */
 public class BPELDateTimeHelpers {

 	// TODO: order must match the DateTimeSelector and DurationSelector values..
 	protected static final int YEAR = 0;
 	protected static final int MONTH = 1;
 	protected static final int DAY = 2;
 	protected static final int HOUR = 3;
 	protected static final int MINUTE = 4;
 	protected static final int SECOND = 5;

 	protected static final String[] dateTimeFormats = {
 		"yyyy","MM","dd","HH","mm","ss" //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$ //$NON-NLS-6$
 	};
 	protected static String dateTimeFormat = "yyyy-MM-ddTHH:mm:ss"; //$NON-NLS-1$

 	// these values are used to populate the Year combo of the DateTimeSelector.
 	// they are also used directly by some helpers below.
 	public static final int yearMin = 2002;
 	public static final int yearMax = Calendar.getInstance().get(Calendar.YEAR) + 5;

 	// Returns the number of consecutive ASCII zeroes in s beginning at position start.
 	protected static int numZeroes(String s, int start) {
 		int i; for (i = start; i<s.length(); i++) if (s.charAt(i) != '0') break;
 		return i-start;
 	}

 	// Returns the number of consecutive ASCII digits in s beginning at position start.
 	protected static int numDigits(String s, int start) {
 		int i; for (i = start; i<s.length(); i++) {
 			char c = s.charAt(i); if ((c < '0') || (c > '9')) break;
 		}
 		return i-start;
 	}

 	protected static int fQuotient(int a, int b) {
 		return (int)Math.floor((double)a/(double)b);
 	}
 	protected static int modulo(int a, int b) {
 		return a-fQuotient(a,b)*b;
 	}
 	protected static int fQuotient3(int a, int low, int high) {
 		return fQuotient(a-low, high-low);
 	}
 	protected static int modulo3(int a, int low, int high) {
 		return modulo(a-low, high-low) + low;
 	}
 	protected static int maximumDayInMonthFor(int yearValue, int monthValue) {
 		int month = modulo3(monthValue, 1, 13);
 		int year = yearValue + fQuotient3(monthValue, 1, 13);
 		return DateTimeSelector.daysInMonth(month-1, year);
 	}

 	public static int[] dateTimePlusDuration(int[] dateTime, int[] duration) {
 		int[] result = new int[6];
 		// This algorithm from XML Schema spec:
 		//http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#adding-durations-to-dateTimes

 	    // months
 		int temp = dateTime[MONTH] + duration[MONTH];
 		result[MONTH] = modulo3(temp, 1, 13);
 		int carry = fQuotient3(temp, 1, 13);
 		// years
 		result[YEAR] = dateTime[YEAR] + duration[YEAR] + carry;
 		// seconds
 		temp = dateTime[SECOND] + duration[SECOND];
 		result[SECOND] = modulo(temp,60);
 		carry = fQuotient(temp,60);
 		// minutes
 		temp = dateTime[MINUTE] + duration[MINUTE] + carry;
 		result[MINUTE] = modulo(temp,60);
 		carry = fQuotient(temp,60);
 		// hours
 		temp = dateTime[HOUR] + duration[HOUR] + carry;
 		result[HOUR] = modulo(temp,24);
 		carry = fQuotient(temp,24);
 		// days

 		int tempDays;
 		if (dateTime[DAY] > maximumDayInMonthFor(result[YEAR], result[MONTH])) {
 			tempDays = maximumDayInMonthFor(result[YEAR], result[MONTH]);
 		} else if (dateTime[DAY] < 1) {
 			tempDays = 1;
 		} else {
 			tempDays = dateTime[DAY];
 		}
 		result[DAY] = tempDays + duration[DAY] + carry;
 		for (;;) {
 			if (result[DAY] < 1) {
 				result[DAY] = result[DAY] + maximumDayInMonthFor(result[YEAR],result[MONTH]-1);
 				carry = -1;
 			} else if (result[DAY] > maximumDayInMonthFor(result[YEAR], result[MONTH])) {
 				result[DAY] = result[DAY] - maximumDayInMonthFor(result[YEAR], result[MONTH]);
 				carry = 1;
 			} else break;
 			temp = result[MONTH] + carry;
 			result[MONTH] = modulo3(temp,1,13);
 			result[YEAR] = result[YEAR] + fQuotient3(temp,1,13);
 		}

 		return result;
 	}

 	/**
 	 * This method reads an XPath string and tries to parse it into a DateTime.
 	 * The string MUST conform to the XML Schema DateTime type or parsing will fail.
 	 * Returns an int[6] array if parsing is successful, or null if it fails.
 	 *
 	 * If the isValidFrom flag is true, any timezone specifier is IGNORED and UTC
 	 * is assumed.  It will also accept a value WITHOUT QUOTES AROUND IT if this
 	 * flag is true.
 	 *
 	 * TODO: this doesn't support negative fields, fractional seconds or years
 	 * greater than Integer.MAX_VALUE.
 	 *
 	 */
 	public static int[] parseXPathDateTime(String xpath, boolean isValidFrom) {
 		int[] v = new int[6];
 		if (xpath == null) return null;

 		String s = removeLiteralQuotes(xpath);
 		if (s == null && !isValidFrom) return null;
 		if (s != null) xpath = s;

 		if (xpath.length() < 19) return null;

 		// The year field must be at least 4 digits (padded with leading zeroes), but if
 		// the year is greater than 999, the year field may not contain leading zeroes.
 		int i = numDigits(xpath,0);
 		if (i<4) return null;
 		int j = numZeroes(xpath,0);
 		if ((i>4) && (j>0)) return null;
 		if (j > 3) return null;  // year 0 is not allowed

 		if (xpath.length() < 15+i) return null;

 		try {
 			v[YEAR] = Integer.parseInt(xpath.substring(j,i));
 			if (v[YEAR] < yearMin || v[YEAR] > yearMax) return null;

 			if (xpath.charAt(i++) != '-') return null;
 			if (numDigits(xpath,i) != 2) return null;
 			v[MONTH] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
 			if (v[MONTH] < 1 || v[MONTH] > 12) return null;

 			if (xpath.charAt(i++) != '-') return null;
 			if (numDigits(xpath,i) != 2) return null;
 			v[DAY] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
 			if (v[DAY] < 1 || v[DAY] > DateTimeSelector.daysInMonth(v[MONTH]-1, v[YEAR])) return null;

 			if (xpath.charAt(i++) != 'T') return null;
 			if (numDigits(xpath,i) != 2) return null;
 			v[HOUR] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
 			if (v[HOUR] < 0 || v[HOUR] > 23) return null;

 			if (xpath.charAt(i++) != ':') return null;
 			if (numDigits(xpath,i) != 2) return null;
 			v[MINUTE] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
 			if (v[MINUTE] < 0 || v[MINUTE] > 59) return null;

 			if (xpath.charAt(i++) != ':') return null;
 			if (numDigits(xpath,i) != 2) return null;
 			v[SECOND] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
 			if (v[SECOND] < 0 || v[SECOND] > 59) return null;
 			if (xpath.length() == i) {
 				// no timezone indicator
 				// if isValidFrom is true, we assume it means UTC anyways
 				if (isValidFrom) return v;
 				// treat it as local time--convert it to UTC and return.
 				convertLocalToGMT(v); return v;
 			}
 			if (xpath.charAt(i) == '.') {
 				// discard fractional seconds.
 				++i; i += numDigits(xpath, i);
 			}

 			int[] delta = new int[6];
 			boolean neg = false;
 			switch (xpath.charAt(i++)) {
 			case 'Z':
 				// UTC timezone.  we're done.
 				return (xpath.length() == i)? v : null;
 			case '-': neg=true;  // fall through
 			case '+':
 				if (xpath.length() != i+5) return null;
 				if (numDigits(xpath,i) != 2) return null;
 				delta[HOUR] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
 				if ((delta[HOUR] < 0) || (delta[HOUR] > 23)) return null;
 				if (xpath.charAt(i++) != ':') return null;
 				if (numDigits(xpath,i) != 2) return null;
 				delta[MINUTE] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
 				if ((delta[MINUTE] < 0) || (delta[MINUTE] > 59)) return null;
 				break;
 			}
 			if (neg) delta[HOUR] = -delta[HOUR];
 			if (xpath.length() != i) return null;
 			if (isValidFrom) {
 				// if isValidFrom is true, we ignore any specified timezone!
 				return v;
 			}
 			return dateTimePlusDuration(v,delta);
 		} catch (NumberFormatException e) {
 			return null;
 		} catch (NullPointerException e) {
 			// hack
 			return null;
 		}
 	}

 	/**
 	 * This method will return a substring with either matching sinqle quotes or matching
 	 * double quotes removed.  If there weren't matching quotes, it returns null.
 	 */
 	public static String removeLiteralQuotes(String s) {
 		if (s.length() < 2) return null;
 		if (s.charAt(0) != '\"' || s.charAt(s.length()-1) != '\"') {
 			if (s.charAt(0) != '\'' || s.charAt(s.length()-1) != '\'') {
 				return null;
 			}
 		}
 		return s.substring(1,s.length()-1);
 	}

 	/**
 	 * This method formats an array int[6] of dateTime values into an XPath string.
 	 * The resulting string complies with the XML Schema DateTime type.
 	 * If the values are invalid and can't be formatted, null is returned.
 	 *
 	 * If the isValidFrom flag is true, the UTC specifier "Z" is not appended,
 	 * and literal quotes are not added around the text.
 	 */
 	public static String createXPathDateTime(int[] dateTime, boolean isValidFrom) {
 		StringBuffer result = new StringBuffer(dateTimeFormat);
 		for (int i = 0; i<6; i++) {
 			String s = String.valueOf(dateTime[i]);
 			if (s.length() < ((i==YEAR)?4:2))  s = "0"+s; //$NON-NLS-1$
 			setValueToStringBuffer(dateTimeFormat, result, s, dateTimeFormats[i]);
 		}
 		if (isValidFrom) return result.toString();
 		return "\'"+result.toString()+"Z\'"; //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	/**
 	 * Returns an int[6] array representing the current DateTime in the local timezone.
 	 */
 	public static int[] getCurrentLocalDateTime() {
 		int[] dateTime = new int[6];
 		Calendar local = new GregorianCalendar();
 		dateTime[YEAR]   = local.get(Calendar.YEAR);
 		dateTime[MONTH]  = local.get(Calendar.MONTH)+1;
 		dateTime[DAY]    = local.get(Calendar.DATE);
 		dateTime[HOUR]   = local.get(Calendar.HOUR_OF_DAY);
 		dateTime[MINUTE] = local.get(Calendar.MINUTE);
 		dateTime[SECOND] = local.get(Calendar.SECOND);
 		return dateTime;
 	}

 	/**
 	 * Use this method on values returned from a DateTimeSelector, if you want the
 	 * selector to show local time but serialize to GMT.
 	 */
 	public static void convertLocalToGMT(int[] dateTime) {
 		// convert local timezone to GMT.
 		Calendar local = new GregorianCalendar();
 		local.set(dateTime[YEAR],dateTime[MONTH],dateTime[DAY],
 			dateTime[HOUR],dateTime[MINUTE],dateTime[SECOND]);
 		Calendar GMTcal = new GregorianCalendar(TimeZone.getTimeZone("GMT+0")); //$NON-NLS-1$
 		GMTcal.setTime(local.getTime());
 		dateTime[YEAR]   = GMTcal.get(Calendar.YEAR);
 		dateTime[MONTH]  = GMTcal.get(Calendar.MONTH);
 		dateTime[DAY]    = GMTcal.get(Calendar.DATE);
 		dateTime[HOUR]   = GMTcal.get(Calendar.HOUR_OF_DAY);
 		dateTime[MINUTE] = GMTcal.get(Calendar.MINUTE);
 		dateTime[SECOND] = GMTcal.get(Calendar.SECOND);
 	}

 	/**
 	 * Use this method on values before storing them in a DateTimeSelector, if you
 	 * want the selector to show local time but serialize to GMT.
 	 */
 	public static void convertGMTToLocal(int [] dateTime) {
 		// convert GMT to local timezone
 		Calendar GMTcal = new GregorianCalendar(TimeZone.getTimeZone("GMT+0")); //$NON-NLS-1$
 		GMTcal.set(dateTime[YEAR],dateTime[MONTH],dateTime[DAY],
 			dateTime[HOUR],dateTime[MINUTE],dateTime[SECOND]);
 		Calendar local = new GregorianCalendar();
 		local.setTime(GMTcal.getTime());
 		dateTime[YEAR]   = local.get(Calendar.YEAR);
 		dateTime[MONTH]  = local.get(Calendar.MONTH);
 		dateTime[DAY]    = local.get(Calendar.DATE);
 		dateTime[HOUR]   = local.get(Calendar.HOUR_OF_DAY);
 		dateTime[MINUTE] = local.get(Calendar.MINUTE);
 		dateTime[SECOND] = local.get(Calendar.SECOND);
 	}


 //	private static String getValueFromString(String format, String dateString, String unit){
 //		int beginIdx = format.indexOf(unit);
 //		if (beginIdx < 0)  return null;
 //		int endIdx = beginIdx + unit.length();
 //		if (beginIdx > dateString.length() || endIdx > dateString.length()) return null;
 //		return dateString.substring(beginIdx, endIdx);
 //	}
 	private static void setValueToStringBuffer(String format, StringBuffer dateBuffer, String value, String unit) {
 		int beginIdx = format.indexOf(unit);
 		if (beginIdx < 0)  return;
 		int endIdx = beginIdx + unit.length();
 		dateBuffer.replace(beginIdx, endIdx, value);
 	}

 	/**
 	 * This method reads an XPath string and tries to parse it into a Duration.
 	 * The string MUST conform to the XML Schema Duration type or parsing will fail.
 	 * Returns an int[6] array if parsing is successful, or null if it fails.
 	 *
 	 * Note that the string should begin and end with a single quote.
 	 */
 	public static int[] parseXPathDuration(String dtStr) {
 		if (dtStr == null) return null;
 		dtStr = removeLiteralQuotes(dtStr);
 		if (dtStr == null) return null;

 		int pos = 0;

 		if (dtStr.length() < 3)  return null;
 		if (dtStr.charAt(pos++) != 'P')  return null;
 		if (dtStr.endsWith("P") || dtStr.endsWith("T"))  return null; //$NON-NLS-1$ //$NON-NLS-2$

 		int[] value = new int[6];

 		StringBuffer digits = new StringBuffer();
 		boolean timePart = false;
 		for (int i = 0; i<6; i++) {
 			if (pos == dtStr.length())  break;
 			if (dtStr.charAt(pos) == 'T')  {
 				pos++;
 				if (timePart)  return null;
 				timePart = true;
 			}
 			digits.setLength(0);
 			while (Character.isDigit(dtStr.charAt(pos))) {
 			    digits.append(dtStr.charAt(pos++));
 			    // We reached the end of the string without finding another letter.
 			    if (pos >= dtStr.length()) return null;
 			}

 			// Skip unused terms.  Note that M is used both in the date part and the time part.
 			switch (dtStr.charAt(pos++))  {
 			case 'Y': if (timePart || i>0) return null; i = 0; break;
 			case 'M': if (i > (timePart?4:1)) return null; i = timePart?4:1; break;
 			case 'D': if (timePart || i>2) return null; i = 2; break;
 			case 'H': if (!timePart || i>3) return null; i = 3; break;
 			case 'S': if (!timePart || i>5) return null; i = 5; break;
 			default: return null;
 			}
 			try {
 				value[i] = Integer.parseInt(digits.toString());
 				if (value[i] < 0)  return null;
 			} catch (NumberFormatException e) {
 				return null;
 			}
 		}
 		return value;
 	}

 	/**
 	 * This method formats an array int[6] of dateTime values into an XPath string.
 	 * The resulting string is in ISO 8601 extended format and complies with the
 	 * XML Schema Duration type.
 	 * If the values are invalid and can't be formatted, null is returned.
 	 */
 	public static String createXPathDuration(int[] duration) {
 		String result = "P"; //$NON-NLS-1$
 		String spec = "YMDHMS"; //$NON-NLS-1$

 		boolean timePart = false;
 		for (int i = 0; i<6; i++)  {
 			int nv = duration[i];
 			if (nv > 0) {
 				if (i >= 3 && !timePart) { timePart = true; result += "T"; }  //$NON-NLS-1$
 				result += nv; result += spec.charAt(i);
 			}
 		}
 		return ("P".equals(result))? "\'P0D\'" : "\'" + result + "\'"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2005, 2012 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.bpel.ui.util;

	import java.util.Calendar;
	import java.util.GregorianCalendar;
	import java.util.TimeZone;

	import org.eclipse.bpel.ui.properties.DateTimeSelector;


	/**
	* Helpers for interacting with DateTimeSelector and DurationSelector widgets, and
	* serializing their values to XPath.
	*/
	public class BPELDateTimeHelpers {

	// TODO: order must match the DateTimeSelector and DurationSelector values..
	protected static final int YEAR = 0;
	protected static final int MONTH = 1;
	protected static final int DAY = 2;
	protected static final int HOUR = 3;
	protected static final int MINUTE = 4;
	protected static final int SECOND = 5;

	protected static final String[] dateTimeFormats = {
	"yyyy","MM","dd","HH","mm","ss" //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$ //$NON-NLS-6$
	};
	protected static String dateTimeFormat = "yyyy-MM-ddTHH:mm:ss"; //$NON-NLS-1$

	// these values are used to populate the Year combo of the DateTimeSelector.
	// they are also used directly by some helpers below.
	public static final int yearMin = 2002;
	public static final int yearMax = Calendar.getInstance().get(Calendar.YEAR) + 5;

	// Returns the number of consecutive ASCII zeroes in s beginning at position start.
	protected static int numZeroes(String s, int start) {
	int i; for (i = start; i<s.length(); i++) if (s.charAt(i) != '0') break;
	return i-start;
	}

	// Returns the number of consecutive ASCII digits in s beginning at position start.
	protected static int numDigits(String s, int start) {
	int i; for (i = start; i<s.length(); i++) {
	char c = s.charAt(i); if ((c < '0') \|\| (c > '9')) break;
	}
	return i-start;
	}

	protected static int fQuotient(int a, int b) {
	return (int)Math.floor((double)a/(double)b);
	}
	protected static int modulo(int a, int b) {
	return a-fQuotient(a,b)*b;
	}
	protected static int fQuotient3(int a, int low, int high) {
	return fQuotient(a-low, high-low);
	}
	protected static int modulo3(int a, int low, int high) {
	return modulo(a-low, high-low) + low;
	}
	protected static int maximumDayInMonthFor(int yearValue, int monthValue) {
	int month = modulo3(monthValue, 1, 13);
	int year = yearValue + fQuotient3(monthValue, 1, 13);
	return DateTimeSelector.daysInMonth(month-1, year);
	}

	public static int[] dateTimePlusDuration(int[] dateTime, int[] duration) {
	int[] result = new int[6];
	// This algorithm from XML Schema spec:
	//http://www.w3.org/TR/2001/REC-xmlschema-2-20010502/#adding-durations-to-dateTimes

	// months
	int temp = dateTime[MONTH] + duration[MONTH];
	result[MONTH] = modulo3(temp, 1, 13);
	int carry = fQuotient3(temp, 1, 13);
	// years
	result[YEAR] = dateTime[YEAR] + duration[YEAR] + carry;
	// seconds
	temp = dateTime[SECOND] + duration[SECOND];
	result[SECOND] = modulo(temp,60);
	carry = fQuotient(temp,60);
	// minutes
	temp = dateTime[MINUTE] + duration[MINUTE] + carry;
	result[MINUTE] = modulo(temp,60);
	carry = fQuotient(temp,60);
	// hours
	temp = dateTime[HOUR] + duration[HOUR] + carry;
	result[HOUR] = modulo(temp,24);
	carry = fQuotient(temp,24);
	// days

	int tempDays;
	if (dateTime[DAY] > maximumDayInMonthFor(result[YEAR], result[MONTH])) {
	tempDays = maximumDayInMonthFor(result[YEAR], result[MONTH]);
	} else if (dateTime[DAY] < 1) {
	tempDays = 1;
	} else {
	tempDays = dateTime[DAY];
	}
	result[DAY] = tempDays + duration[DAY] + carry;
	for (;;) {
	if (result[DAY] < 1) {
	result[DAY] = result[DAY] + maximumDayInMonthFor(result[YEAR],result[MONTH]-1);
	carry = -1;
	} else if (result[DAY] > maximumDayInMonthFor(result[YEAR], result[MONTH])) {
	result[DAY] = result[DAY] - maximumDayInMonthFor(result[YEAR], result[MONTH]);
	carry = 1;
	} else break;
	temp = result[MONTH] + carry;
	result[MONTH] = modulo3(temp,1,13);
	result[YEAR] = result[YEAR] + fQuotient3(temp,1,13);
	}

	return result;
	}

	/**
	* This method reads an XPath string and tries to parse it into a DateTime.
	* The string MUST conform to the XML Schema DateTime type or parsing will fail.
	* Returns an int[6] array if parsing is successful, or null if it fails.
	*
	* If the isValidFrom flag is true, any timezone specifier is IGNORED and UTC
	* is assumed. It will also accept a value WITHOUT QUOTES AROUND IT if this
	* flag is true.
	*
	* TODO: this doesn't support negative fields, fractional seconds or years
	* greater than Integer.MAX_VALUE.
	*
	*/
	public static int[] parseXPathDateTime(String xpath, boolean isValidFrom) {
	int[] v = new int[6];
	if (xpath == null) return null;

	String s = removeLiteralQuotes(xpath);
	if (s == null && !isValidFrom) return null;
	if (s != null) xpath = s;

	if (xpath.length() < 19) return null;

	// The year field must be at least 4 digits (padded with leading zeroes), but if
	// the year is greater than 999, the year field may not contain leading zeroes.
	int i = numDigits(xpath,0);
	if (i<4) return null;
	int j = numZeroes(xpath,0);
	if ((i>4) && (j>0)) return null;
	if (j > 3) return null; // year 0 is not allowed

	if (xpath.length() < 15+i) return null;

	try {
	v[YEAR] = Integer.parseInt(xpath.substring(j,i));
	if (v[YEAR] < yearMin \|\| v[YEAR] > yearMax) return null;

	if (xpath.charAt(i++) != '-') return null;
	if (numDigits(xpath,i) != 2) return null;
	v[MONTH] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
	if (v[MONTH] < 1 \|\| v[MONTH] > 12) return null;

	if (xpath.charAt(i++) != '-') return null;
	if (numDigits(xpath,i) != 2) return null;
	v[DAY] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
	if (v[DAY] < 1 \|\| v[DAY] > DateTimeSelector.daysInMonth(v[MONTH]-1, v[YEAR])) return null;

	if (xpath.charAt(i++) != 'T') return null;
	if (numDigits(xpath,i) != 2) return null;
	v[HOUR] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
	if (v[HOUR] < 0 \|\| v[HOUR] > 23) return null;

	if (xpath.charAt(i++) != ':') return null;
	if (numDigits(xpath,i) != 2) return null;
	v[MINUTE] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
	if (v[MINUTE] < 0 \|\| v[MINUTE] > 59) return null;

	if (xpath.charAt(i++) != ':') return null;
	if (numDigits(xpath,i) != 2) return null;
	v[SECOND] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
	if (v[SECOND] < 0 \|\| v[SECOND] > 59) return null;
	if (xpath.length() == i) {
	// no timezone indicator
	// if isValidFrom is true, we assume it means UTC anyways
	if (isValidFrom) return v;
	// treat it as local time--convert it to UTC and return.
	convertLocalToGMT(v); return v;
	}
	if (xpath.charAt(i) == '.') {
	// discard fractional seconds.
	++i; i += numDigits(xpath, i);
	}

	int[] delta = new int[6];
	boolean neg = false;
	switch (xpath.charAt(i++)) {
	case 'Z':
	// UTC timezone. we're done.
	return (xpath.length() == i)? v : null;
	case '-': neg=true; // fall through
	case '+':
	if (xpath.length() != i+5) return null;
	if (numDigits(xpath,i) != 2) return null;
	delta[HOUR] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
	if ((delta[HOUR] < 0) \|\| (delta[HOUR] > 23)) return null;
	if (xpath.charAt(i++) != ':') return null;
	if (numDigits(xpath,i) != 2) return null;
	delta[MINUTE] = Integer.parseInt(xpath.substring(i,i+2)); i += 2;
	if ((delta[MINUTE] < 0) \|\| (delta[MINUTE] > 59)) return null;
	break;
	}
	if (neg) delta[HOUR] = -delta[HOUR];
	if (xpath.length() != i) return null;
	if (isValidFrom) {
	// if isValidFrom is true, we ignore any specified timezone!
	return v;
	}
	return dateTimePlusDuration(v,delta);
	} catch (NumberFormatException e) {
	return null;
	} catch (NullPointerException e) {
	// hack
	return null;
	}
	}

	/**
	* This method will return a substring with either matching sinqle quotes or matching
	* double quotes removed. If there weren't matching quotes, it returns null.
	*/
	public static String removeLiteralQuotes(String s) {
	if (s.length() < 2) return null;
	if (s.charAt(0) != '\"' \|\| s.charAt(s.length()-1) != '\"') {
	if (s.charAt(0) != '\'' \|\| s.charAt(s.length()-1) != '\'') {
	return null;
	}
	}
	return s.substring(1,s.length()-1);
	}

	/**
	* This method formats an array int[6] of dateTime values into an XPath string.
	* The resulting string complies with the XML Schema DateTime type.
	* If the values are invalid and can't be formatted, null is returned.
	*
	* If the isValidFrom flag is true, the UTC specifier "Z" is not appended,
	* and literal quotes are not added around the text.
	*/
	public static String createXPathDateTime(int[] dateTime, boolean isValidFrom) {
	StringBuffer result = new StringBuffer(dateTimeFormat);
	for (int i = 0; i<6; i++) {
	String s = String.valueOf(dateTime[i]);
	if (s.length() < ((i==YEAR)?4:2)) s = "0"+s; //$NON-NLS-1$
	setValueToStringBuffer(dateTimeFormat, result, s, dateTimeFormats[i]);
	}
	if (isValidFrom) return result.toString();
	return "\'"+result.toString()+"Z\'"; //$NON-NLS-1$ //$NON-NLS-2$
	}

	/**
	* Returns an int[6] array representing the current DateTime in the local timezone.
	*/
	public static int[] getCurrentLocalDateTime() {
	int[] dateTime = new int[6];
	Calendar local = new GregorianCalendar();
	dateTime[YEAR] = local.get(Calendar.YEAR);
	dateTime[MONTH] = local.get(Calendar.MONTH)+1;
	dateTime[DAY] = local.get(Calendar.DATE);
	dateTime[HOUR] = local.get(Calendar.HOUR_OF_DAY);
	dateTime[MINUTE] = local.get(Calendar.MINUTE);
	dateTime[SECOND] = local.get(Calendar.SECOND);
	return dateTime;
	}

	/**
	* Use this method on values returned from a DateTimeSelector, if you want the
	* selector to show local time but serialize to GMT.
	*/
	public static void convertLocalToGMT(int[] dateTime) {
	// convert local timezone to GMT.
	Calendar local = new GregorianCalendar();
	local.set(dateTime[YEAR],dateTime[MONTH],dateTime[DAY],
	dateTime[HOUR],dateTime[MINUTE],dateTime[SECOND]);
	Calendar GMTcal = new GregorianCalendar(TimeZone.getTimeZone("GMT+0")); //$NON-NLS-1$
	GMTcal.setTime(local.getTime());
	dateTime[YEAR] = GMTcal.get(Calendar.YEAR);
	dateTime[MONTH] = GMTcal.get(Calendar.MONTH);
	dateTime[DAY] = GMTcal.get(Calendar.DATE);
	dateTime[HOUR] = GMTcal.get(Calendar.HOUR_OF_DAY);
	dateTime[MINUTE] = GMTcal.get(Calendar.MINUTE);
	dateTime[SECOND] = GMTcal.get(Calendar.SECOND);
	}

	/**
	* Use this method on values before storing them in a DateTimeSelector, if you
	* want the selector to show local time but serialize to GMT.
	*/
	public static void convertGMTToLocal(int [] dateTime) {
	// convert GMT to local timezone
	Calendar GMTcal = new GregorianCalendar(TimeZone.getTimeZone("GMT+0")); //$NON-NLS-1$
	GMTcal.set(dateTime[YEAR],dateTime[MONTH],dateTime[DAY],
	dateTime[HOUR],dateTime[MINUTE],dateTime[SECOND]);
	Calendar local = new GregorianCalendar();
	local.setTime(GMTcal.getTime());
	dateTime[YEAR] = local.get(Calendar.YEAR);
	dateTime[MONTH] = local.get(Calendar.MONTH);
	dateTime[DAY] = local.get(Calendar.DATE);
	dateTime[HOUR] = local.get(Calendar.HOUR_OF_DAY);
	dateTime[MINUTE] = local.get(Calendar.MINUTE);
	dateTime[SECOND] = local.get(Calendar.SECOND);
	}


	// private static String getValueFromString(String format, String dateString, String unit){
	// int beginIdx = format.indexOf(unit);
	// if (beginIdx < 0) return null;
	// int endIdx = beginIdx + unit.length();
	// if (beginIdx > dateString.length() \|\| endIdx > dateString.length()) return null;
	// return dateString.substring(beginIdx, endIdx);
	// }
	private static void setValueToStringBuffer(String format, StringBuffer dateBuffer, String value, String unit) {
	int beginIdx = format.indexOf(unit);
	if (beginIdx < 0) return;
	int endIdx = beginIdx + unit.length();
	dateBuffer.replace(beginIdx, endIdx, value);
	}

	/**
	* This method reads an XPath string and tries to parse it into a Duration.
	* The string MUST conform to the XML Schema Duration type or parsing will fail.
	* Returns an int[6] array if parsing is successful, or null if it fails.
	*
	* Note that the string should begin and end with a single quote.
	*/
	public static int[] parseXPathDuration(String dtStr) {
	if (dtStr == null) return null;
	dtStr = removeLiteralQuotes(dtStr);
	if (dtStr == null) return null;

	int pos = 0;

	if (dtStr.length() < 3) return null;
	if (dtStr.charAt(pos++) != 'P') return null;
	if (dtStr.endsWith("P") \|\| dtStr.endsWith("T")) return null; //$NON-NLS-1$ //$NON-NLS-2$

	int[] value = new int[6];

	StringBuffer digits = new StringBuffer();
	boolean timePart = false;
	for (int i = 0; i<6; i++) {
	if (pos == dtStr.length()) break;
	if (dtStr.charAt(pos) == 'T') {
	pos++;
	if (timePart) return null;
	timePart = true;
	}
	digits.setLength(0);
	while (Character.isDigit(dtStr.charAt(pos))) {
	digits.append(dtStr.charAt(pos++));
	// We reached the end of the string without finding another letter.
	if (pos >= dtStr.length()) return null;
	}

	// Skip unused terms. Note that M is used both in the date part and the time part.
	switch (dtStr.charAt(pos++)) {
	case 'Y': if (timePart \|\| i>0) return null; i = 0; break;
	case 'M': if (i > (timePart?4:1)) return null; i = timePart?4:1; break;
	case 'D': if (timePart \|\| i>2) return null; i = 2; break;
	case 'H': if (!timePart \|\| i>3) return null; i = 3; break;
	case 'S': if (!timePart \|\| i>5) return null; i = 5; break;
	default: return null;
	}
	try {
	value[i] = Integer.parseInt(digits.toString());
	if (value[i] < 0) return null;
	} catch (NumberFormatException e) {
	return null;
	}
	}
	return value;
	}

	/**
	* This method formats an array int[6] of dateTime values into an XPath string.
	* The resulting string is in ISO 8601 extended format and complies with the
	* XML Schema Duration type.
	* If the values are invalid and can't be formatted, null is returned.
	*/
	public static String createXPathDuration(int[] duration) {
	String result = "P"; //$NON-NLS-1$
	String spec = "YMDHMS"; //$NON-NLS-1$

	boolean timePart = false;
	for (int i = 0; i<6; i++) {
	int nv = duration[i];
	if (nv > 0) {
	if (i >= 3 && !timePart) { timePart = true; result += "T"; } //$NON-NLS-1$
	result += nv; result += spec.charAt(i);
	}
	}
	return ("P".equals(result))? "\'P0D\'" : "\'" + result + "\'"; //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
	}
	}