/*
 * Copyright (c) 2004, 2006, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.
 */

package javax.xml.datatype;

import java.math.BigInteger;
import java.math.BigDecimal;
import java.util.GregorianCalendar;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * <p>Factory that creates new <code>javax.xml.datatype</code> <code>Object</code>s that map XML to/from Java <code>Object</code>s.</p>
 * 
 * <p><a name="DatatypeFactory.newInstance"/>{@link #newInstance()} is used to create a new <code>DatatypeFactory</code>.
 * The following implementation resolution mechanisms are used in the following order:</p>
 * <ol>
 *    <li>
 *      If the system property specified by {@link #DATATYPEFACTORY_PROPERTY}, "<code>javax.xml.datatype.DatatypeFactory</code>",
 *      exists, a class with the name of the property's value is instantiated.
 *      Any Exception thrown during the instantiation process is wrapped as a {@link DatatypeConfigurationException}.
 *    </li>
 *    <li>
 *      If the file ${JAVA_HOME}/lib/jaxp.properties exists, it is loaded in a {@link java.util.Properties} <code>Object</code>.
 *      The <code>Properties</code> <code>Object </code> is then queried for the property as documented in the prior step
 *      and processed as documented in the prior step.
 *    </li>
 *    <li>
 *      The services resolution mechanism is used, e.g. <code>META-INF/services/java.xml.datatype.DatatypeFactory</code>.
 *      Any Exception thrown during the instantiation process is wrapped as a {@link DatatypeConfigurationException}.
 *    </li>
 *    <li>
 *      The final mechanism is to attempt to instantiate the <code>Class</code> specified by
 *      {@link #DATATYPEFACTORY_IMPLEMENTATION_CLASS}.
 *      Any Exception thrown during the instantiation process is wrapped as a {@link DatatypeConfigurationException}.
 *    </li>
 * </ol> 
 * 
 * @author <a href="mailto:Joseph.Fialli@Sun.COM">Joseph Fialli</a>
 * @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor</a>
 * @author <a href="mailto:Neeraj.Bajaj@sun.com">Neeraj Bajaj</a>
 *
 * @version $Revision: 1.13 $, $Date: 2010/03/11 23:10:53 $
 * @since 1.5
 */
public abstract class DatatypeFactory {
		
	/**
	 * <p>Default property name as defined in JSR 206: Java(TM) API for XML Processing (JAXP) 1.3.</p>
	 * 
	 * <p>Default value is <code>javax.xml.datatype.DatatypeFactory</code>.</p>
	 */
	public static final String DATATYPEFACTORY_PROPERTY = "javax.xml.datatype.DatatypeFactory";

	/**
	 * <p>Default implementation class name as defined in
	 * <em>JSR 206: Java(TM) API for XML Processing (JAXP) 1.3</em>.</p>
	 *
	 * <p>Implementers should specify the name of an appropriate class
	 * to be instantiated if no other implementation resolution mechanism
	 * succeeds.</p>
	 *
	 * <p>Users should not refer to this field; it is intended only to
	 * document a factory implementation detail.
	 * </p>
	 */
	public static final String DATATYPEFACTORY_IMPLEMENTATION_CLASS = new String("com.sun.org.apache.xerces.internal.jaxp.datatype.DatatypeFactoryImpl");
	
    /**
     * http://www.w3.org/TR/xpath-datamodel/#xdtschema defines two regexps
     * to constrain the value space of dayTimeDuration ([^YM]*[DT].*)
     * and yearMonthDuration ([^DT]*). Note that these expressions rely on
     * the fact that the value must be an xs:Duration, they simply exclude
     * some Durations.
     */
    private static final Pattern XDTSCHEMA_YMD =
        Pattern.compile("[^DT]*");

    private static final Pattern XDTSCHEMA_DTD =
        Pattern.compile("[^YM]*[DT].*");

	/**
	 * <p>Protected constructor to prevent instaniation outside of package.</p>
	 * 
	 * <p>Use {@link #newInstance()} to create a <code>DatatypeFactory</code>.</p>
	 */
	protected DatatypeFactory() {
	}
	
	/**
	 * <p>Obtain a new instance of a <code>DatatypeFactory</code>.</p>
	 * 
     * <p>The implementation resolution mechanisms are <a href="#DatatypeFactory.newInstance">defined</a> in this
     * <code>Class</code>'s documentation.</p>
	 * 
	 * @return New instance of a <code>DatatypeFactory</code>
	 *
	 * @throws DatatypeConfigurationException If the implementation is not
	 *   available or cannot be instantiated.
     *
     * @see #newInstance(String factoryClassName, ClassLoader classLoader)
	 */
	public static DatatypeFactory newInstance()
		throws DatatypeConfigurationException {
			
		try {
			return (DatatypeFactory) FactoryFinder.find(
				/* The default property name according to the JAXP spec */
				 DATATYPEFACTORY_PROPERTY,
				/* The fallback implementation class name */
				DATATYPEFACTORY_IMPLEMENTATION_CLASS);
		} catch (FactoryFinder.ConfigurationError e) {
			throw new DatatypeConfigurationException(e.getMessage(), e.getException());
		}
	}
	
    /**
     * <p>Obtain a new instance of a <code>DatatypeFactory</code> from class name.
     * This function is useful when there are multiple providers in the classpath.
     * It gives more control to the application as it can specify which provider
     * should be loaded.</p>
     *
     * <p>Once an application has obtained a reference to a <code>DatatypeFactory</code> 
     * it can use the factory to configure and obtain datatype instances.</P>
     * 
     * 
     * <h2>Tip for Trouble-shooting</h2>
     * <p>Setting the <code>jaxp.debug</code> system property will cause
     * this method to print a lot of debug messages
     * to <code>System.err</code> about what it is doing and where it is looking at.</p>
     * 
     * <p> If you have problems try:</p>
     * <pre>
     * java -Djaxp.debug=1 YourProgram ....
     * </pre>
     * 
     * @param factoryClassName fully qualified factory class name that provides implementation of <code>javax.xml.datatype.DatatypeFactory</code>.
     *
     * @param classLoader <code>ClassLoader</code> used to load the factory class. If <code>null</code>  
     *                     current <code>Thread</code>'s context classLoader is used to load the factory class.
     *
     * @return New instance of a <code>DatatypeFactory</code>
     *
     * @throws DatatypeConfigurationException if <code>factoryClassName</code> is <code>null</code>, or 
     *                                   the factory class cannot be loaded, instantiated.
     *
     * @see #newInstance()
     *
     * @since 1.6
     */
    public static DatatypeFactory newInstance(String factoryClassName, ClassLoader classLoader)
        throws DatatypeConfigurationException {
        try {            
            return (DatatypeFactory) FactoryFinder.newInstance(factoryClassName, classLoader, false);
        } catch (FactoryFinder.ConfigurationError e) {
            throw new DatatypeConfigurationException(e.getMessage(), e.getException());
        }        
    }
    
	/**
	 * <p>Obtain a new instance of a <code>Duration</code>
	 * specifying the <code>Duration</code> as its string representation, "PnYnMnDTnHnMnS",
	 * as defined in XML Schema 1.0 section 3.2.6.1.</p>
	 * 
	 * <p>XML Schema Part 2: Datatypes, 3.2.6 duration, defines <code>duration</code> as:</p>
	 * <blockquote>
	 * duration represents a duration of time.
	 * The value space of duration is a six-dimensional space where the coordinates designate the
	 * Gregorian year, month, day, hour, minute, and second components defined in Section 5.5.3.2 of [ISO 8601], respectively.
	 * These components are ordered in their significance by their order of appearance i.e. as
	 * year, month, day, hour, minute, and second. 
	 * </blockquote>
     * <p>All six values are set and availabe from the created {@link Duration}</p>
     * 
     * <p>The XML Schema specification states that values can be of an arbitrary size.
     * Implementations may chose not to or be incapable of supporting arbitrarily large and/or small values.
     * An {@link UnsupportedOperationException} will be thrown with a message indicating implementation limits
     * if implementation capacities are exceeded.</p>
	 * 
	 * @param lexicalRepresentation <code>String</code> representation of a <code>Duration</code>.
	 * 
	 * @return New <code>Duration</code> created from parsing the <code>lexicalRepresentation</code>.
	 * 
	 * @throws IllegalArgumentException If <code>lexicalRepresentation</code> is not a valid representation of a <code>Duration</code>.
	 * @throws UnsupportedOperationException If implementation cannot support requested values.
	 * @throws NullPointerException if <code>lexicalRepresentation</code> is <code>null</code>.
	 */
	public abstract Duration newDuration(final String lexicalRepresentation);
	
	/**
	 * <p>Obtain a new instance of a <code>Duration</code>
	 * specifying the <code>Duration</code> as milliseconds.</p>
	 * 
	 * <p>XML Schema Part 2: Datatypes, 3.2.6 duration, defines <code>duration</code> as:</p>
	 * <blockquote>
	 * duration represents a duration of time.
	 * The value space of duration is a six-dimensional space where the coordinates designate the
	 * Gregorian year, month, day, hour, minute, and second components defined in Section 5.5.3.2 of [ISO 8601], respectively.
	 * These components are ordered in their significance by their order of appearance i.e. as
	 * year, month, day, hour, minute, and second. 
	 * </blockquote>
     * <p>All six values are set by computing their values from the specified milliseconds
     * and are availabe using the <code>get</code> methods of  the created {@link Duration}.
     * The values conform to and are defined by:</p>
     * <ul>
     *   <li>ISO 8601:2000(E) Section 5.5.3.2 Alternative format</li>
     *   <li><a href="http://www.w3.org/TR/xmlschema-2/#isoformats">
     *     W3C XML Schema 1.0 Part 2, Appendix D, ISO 8601 Date and Time Formats</a>
     *   </li>
     *   <li>{@link XMLGregorianCalendar}  Date/Time Datatype Field Mapping Between XML Schema 1.0 and Java Representation</li>
     * </ul>
	 * 
	 * <p>The default start instance is defined by {@link GregorianCalendar}'s use of the start of the epoch: i.e.,
	 * {@link java.util.Calendar#YEAR} = 1970,
	 * {@link java.util.Calendar#MONTH} = {@link java.util.Calendar#JANUARY},
	 * {@link java.util.Calendar#DATE} = 1, etc.
	 * This is important as there are variations in the Gregorian Calendar,
	 * e.g. leap years have different days in the month = {@link java.util.Calendar#FEBRUARY}
	 * so the result of {@link Duration#getMonths()} and {@link Duration#getDays()} can be influenced.</p> 
	 * 
	 * @param durationInMilliSeconds Duration in milliseconds to create.
	 * 
	 * @return New <code>Duration</code> representing <code>durationInMilliSeconds</code>.
	 */
	public abstract Duration newDuration(final long durationInMilliSeconds);
	
	/**
	 * <p>Obtain a new instance of a <code>Duration</code>
	 * specifying the <code>Duration</code> as isPositive, years, months, days, hours, minutes, seconds.</p>
	 * 
     * <p>The XML Schema specification states that values can be of an arbitrary size.
     * Implementations may chose not to or be incapable of supporting arbitrarily large and/or small values.
     * An {@link UnsupportedOperationException} will be thrown with a message indicating implementation limits
     * if implementation capacities are exceeded.</p>
     * 
     * <p>A <code>null</code> value indicates that field is not set.</p>
     * 
	 * @param isPositive Set to <code>false</code> to create a negative duration. When the length
	 *   of the duration is zero, this parameter will be ignored.
	 * @param years of this <code>Duration</code>
	 * @param months of this <code>Duration</code>
	 * @param days of this <code>Duration</code>
	 * @param hours of this <code>Duration</code>
	 * @param minutes of this <code>Duration</code>
	 * @param seconds of this <code>Duration</code>
	 * 
	 * @return New <code>Duration</code> created from the specified values.
	 * 
	 * @throws IllegalArgumentException If the values are not a valid representation of a
	 * <code>Duration</code>: if all the fields (years, months, ...) are null or
	 * if any of the fields is negative.
	 * @throws UnsupportedOperationException If implementation cannot support requested values.
	 */
	public abstract Duration newDuration(
		final boolean isPositive,
		final BigInteger years,
		final BigInteger months,
		final BigInteger days,
		final BigInteger hours,
		final BigInteger minutes,
		final BigDecimal seconds);

	/**
	 * <p>Obtain a new instance of a <code>Duration</code>
	 * specifying the <code>Duration</code> as isPositive, years, months, days, hours, minutes, seconds.</p>
	 * 
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
     * @param isPositive Set to <code>false</code> to create a negative duration. When the length
     *   of the duration is zero, this parameter will be ignored.
     * @param years of this <code>Duration</code>
     * @param months of this <code>Duration</code>
     * @param days of this <code>Duration</code>
     * @param hours of this <code>Duration</code>
     * @param minutes of this <code>Duration</code>
     * @param seconds of this <code>Duration</code>
     * 
	 * @return New <code>Duration</code> created from the specified values.
	 * 
	 * @throws IllegalArgumentException If the values are not a valid representation of a
	 * <code>Duration</code>: if any of the fields is negative.
	 * 
	 * @see #newDuration(
	 *   boolean isPositive,
	 *   BigInteger years,
	 *   BigInteger months,
	 *   BigInteger days,
	 *   BigInteger hours,
	 *   BigInteger minutes,
	 *   BigDecimal seconds)
	 */
	public Duration newDuration(
		final boolean isPositive,
		final int years,
		final int months,
		final int days,
		final int hours,
		final int minutes,
		final int seconds) {
			
		// years may not be set
		BigInteger realYears = (years != DatatypeConstants.FIELD_UNDEFINED) ? BigInteger.valueOf((long) years) : null;
			
		// months may not be set
		BigInteger realMonths = (months != DatatypeConstants.FIELD_UNDEFINED) ? BigInteger.valueOf((long) months) : null;

		// days may not be set
		BigInteger realDays = (days != DatatypeConstants.FIELD_UNDEFINED) ? BigInteger.valueOf((long) days) : null;

		// hours may not be set
		BigInteger realHours = (hours != DatatypeConstants.FIELD_UNDEFINED) ? BigInteger.valueOf((long) hours) : null;

		// minutes may not be set
		BigInteger realMinutes = (minutes != DatatypeConstants.FIELD_UNDEFINED) ? BigInteger.valueOf((long) minutes) : null;
		
		// seconds may not be set
		BigDecimal realSeconds = (seconds != DatatypeConstants.FIELD_UNDEFINED) ? BigDecimal.valueOf((long) seconds) : null;

			return newDuration(
				isPositive,
				realYears,
				realMonths,
				realDays,
				realHours,
				realMinutes,
				realSeconds
			);
		}
		
	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:dayTimeDuration</code> by parsing its <code>String</code> representation,
	 * "<em>PnDTnHnMnS</em>", <a href="http://www.w3.org/TR/xpath-datamodel#dayTimeDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:dayTimeDuration</a>.</p>
	 * 
	 * <p>The datatype <code>xdt:dayTimeDuration</code> is a subtype of <code>xs:duration</code>
	 * whose lexical representation contains only day, hour, minute, and second components.
	 * This datatype resides in the namespace <code>http://www.w3.org/2003/11/xpath-datatypes</code>.</p>
	 * 
     * <p>All four values are set and availabe from the created {@link Duration}</p>
	 * 
     * <p>The XML Schema specification states that values can be of an arbitrary size.
     * Implementations may chose not to or be incapable of supporting arbitrarily large and/or small values.
     * An {@link UnsupportedOperationException} will be thrown with a message indicating implementation limits
     * if implementation capacities are exceeded.</p>
     * 
	 * @param lexicalRepresentation Lexical representation of a duration.
	 * 
	 * @return New <code>Duration</code> created using the specified <code>lexicalRepresentation</code>.
	 * 
	 * @throws IllegalArgumentException If <code>lexicalRepresentation</code> is not a valid representation of a <code>Duration</code> expressed only in terms of days and time.
	 * @throws UnsupportedOperationException If implementation cannot support requested values.
	 * @throws NullPointerException If <code>lexicalRepresentation</code> is <code>null</code>.
	 */
	public Duration newDurationDayTime(final String lexicalRepresentation) {
	    // lexicalRepresentation must be non-null
	    if (lexicalRepresentation == null) {
		throw new NullPointerException(
                    "Trying to create an xdt:dayTimeDuration with an invalid"
                    + " lexical representation of \"null\"");
	    }

	    // test lexicalRepresentation against spec regex
	    Matcher matcher = XDTSCHEMA_DTD.matcher(lexicalRepresentation);
	    if (!matcher.matches()) {
		throw new IllegalArgumentException(
                    "Trying to create an xdt:dayTimeDuration with an invalid"
                    + " lexical representation of \"" + lexicalRepresentation
                    + "\", data model requires years and months only.");
	    }

	    return newDuration(lexicalRepresentation);
	}

	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:dayTimeDuration</code> using the specified milliseconds as defined in
	 * <a href="http://www.w3.org/TR/xpath-datamodel#dayTimeDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:dayTimeDuration</a>.</p>
	 * 
	 * <p>The datatype <code>xdt:dayTimeDuration</code> is a subtype of <code>xs:duration</code>
	 * whose lexical representation contains only day, hour, minute, and second components.
	 * This datatype resides in the namespace <code>http://www.w3.org/2003/11/xpath-datatypes</code>.</p>
	 * 
     * <p>All four values are set by computing their values from the specified milliseconds
     * and are availabe using the <code>get</code> methods of  the created {@link Duration}.
     * The values conform to and are defined by:</p>
     * <ul>
     *   <li>ISO 8601:2000(E) Section 5.5.3.2 Alternative format</li>
     *   <li><a href="http://www.w3.org/TR/xmlschema-2/#isoformats">
     *     W3C XML Schema 1.0 Part 2, Appendix D, ISO 8601 Date and Time Formats</a>
     *   </li>
     *   <li>{@link XMLGregorianCalendar}  Date/Time Datatype Field Mapping Between XML Schema 1.0 and Java Representation</li>
     * </ul>
	 * 
	 * <p>The default start instance is defined by {@link GregorianCalendar}'s use of the start of the epoch: i.e.,
	 * {@link java.util.Calendar#YEAR} = 1970,
	 * {@link java.util.Calendar#MONTH} = {@link java.util.Calendar#JANUARY},
	 * {@link java.util.Calendar#DATE} = 1, etc.
	 * This is important as there are variations in the Gregorian Calendar,
	 * e.g. leap years have different days in the month = {@link java.util.Calendar#FEBRUARY}
	 * so the result of {@link Duration#getDays()} can be influenced.</p>
	 * 
     * <p>Any remaining milliseconds after determining the day, hour, minute and second are discarded.</p>
     * 
	 * @param durationInMilliseconds Milliseconds of <code>Duration</code> to create.
	 * 
	 * @return New <code>Duration</code> created with the specified <code>durationInMilliseconds</code>.
	 * 
	 * @see <a href="http://www.w3.org/TR/xpath-datamodel#dayTimeDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:dayTimeDuration</a>
	 */
	public Duration newDurationDayTime(final long durationInMilliseconds) {
		
		return newDuration(durationInMilliseconds);
	}
		
	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:dayTimeDuration</code> using the specified
	 * <code>day</code>, <code>hour</code>, <code>minute</code> and <code>second</code> as defined in
	 * <a href="http://www.w3.org/TR/xpath-datamodel#dayTimeDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:dayTimeDuration</a>.</p>
	 * 
	 * <p>The datatype <code>xdt:dayTimeDuration</code> is a subtype of <code>xs:duration</code>
	 * whose lexical representation contains only day, hour, minute, and second components.
	 * This datatype resides in the namespace <code>http://www.w3.org/2003/11/xpath-datatypes</code>.</p>
	 * 
     * <p>The XML Schema specification states that values can be of an arbitrary size.
     * Implementations may chose not to or be incapable of supporting arbitrarily large and/or small values.
     * An {@link UnsupportedOperationException} will be thrown with a message indicating implementation limits
     * if implementation capacities are exceeded.</p>
     * 
     * <p>A <code>null</code> value indicates that field is not set.</p>
     * 
     * @param isPositive Set to <code>false</code> to create a negative duration. When the length
     *   of the duration is zero, this parameter will be ignored.
	 * @param day Day of <code>Duration</code>.
	 * @param hour Hour of <code>Duration</code>.
	 * @param minute Minute of <code>Duration</code>.
	 * @param second Second of <code>Duration</code>.
	 * 
	 * @return New <code>Duration</code> created with the specified <code>day</code>, <code>hour</code>, <code>minute</code>
	 * and <code>second</code>.
	 * 
	 * @throws IllegalArgumentException If the values are not a valid representation of a
	 * <code>Duration</code>: if all the fields (day, hour, ...) are null or
	 * if any of the fields is negative.
	 * @throws UnsupportedOperationException If implementation cannot support requested values.
	 */	
	public Duration newDurationDayTime(
		final boolean isPositive,
		final BigInteger day,
		final BigInteger hour,
		final BigInteger minute,
		final BigInteger second) {
			
		return newDuration(
			isPositive,
			null,  // years
			null, // months
			day,
			hour,
			minute,
			(second != null)? new BigDecimal(second):null
		);
	}
		
	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:dayTimeDuration</code> using the specified
	 * <code>day</code>, <code>hour</code>, <code>minute</code> and <code>second</code> as defined in
	 * <a href="http://www.w3.org/TR/xpath-datamodel#dayTimeDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:dayTimeDuration</a>.</p>
	 * 
	 * <p>The datatype <code>xdt:dayTimeDuration</code> is a subtype of <code>xs:duration</code>
	 * whose lexical representation contains only day, hour, minute, and second components.
	 * This datatype resides in the namespace <code>http://www.w3.org/2003/11/xpath-datatypes</code>.</p>
	 * 
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
     * @param isPositive Set to <code>false</code> to create a negative duration. When the length
     *   of the duration is zero, this parameter will be ignored.
	 * @param day Day of <code>Duration</code>.
	 * @param hour Hour of <code>Duration</code>.
	 * @param minute Minute of <code>Duration</code>.
	 * @param second Second of <code>Duration</code>.
	 * 
	 * @return New <code>Duration</code> created with the specified <code>day</code>, <code>hour</code>, <code>minute</code>
	 * and <code>second</code>.
	 * 
	 * @throws IllegalArgumentException If the values are not a valid representation of a
	 * <code>Duration</code>: if any of the fields (day, hour, ...) is negative.
	 */	
	public Duration newDurationDayTime(
		final boolean isPositive,
		final int day,
		final int hour,
		final int minute,
		final int second) {
			
			return newDurationDayTime(
				isPositive,
				BigInteger.valueOf((long) day),
				BigInteger.valueOf((long) hour),
				BigInteger.valueOf((long) minute),
				BigInteger.valueOf((long) second)
				);
		}

	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:yearMonthDuration</code> by parsing its <code>String</code> representation,
	 * "<em>PnYnM</em>", <a href="http://www.w3.org/TR/xpath-datamodel#yearMonthDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:yearMonthDuration</a>.</p>
	 * 
	 * <p>The datatype <code>xdt:yearMonthDuration</code> is a subtype of <code>xs:duration</code>
	 * whose lexical representation contains only year and month components.
	 * This datatype resides in the namespace {@link javax.xml.XMLConstants#W3C_XPATH_DATATYPE_NS_URI}.</p>
	 * 
     * <p>Both values are set and availabe from the created {@link Duration}</p>
	 * 
     * <p>The XML Schema specification states that values can be of an arbitrary size.
     * Implementations may chose not to or be incapable of supporting arbitrarily large and/or small values.
     * An {@link UnsupportedOperationException} will be thrown with a message indicating implementation limits
     * if implementation capacities are exceeded.</p>
     * 
	 * @param lexicalRepresentation Lexical representation of a duration.
	 * 
	 * @return New <code>Duration</code> created using the specified <code>lexicalRepresentation</code>.
	 * 
	 * @throws IllegalArgumentException If <code>lexicalRepresentation</code> is not a valid representation of a <code>Duration</code> expressed only in terms of years and months.
	 * @throws UnsupportedOperationException If implementation cannot support requested values.
	 * @throws NullPointerException If <code>lexicalRepresentation</code> is <code>null</code>.
	 */
    public Duration newDurationYearMonth(
            final String lexicalRepresentation) {

        // lexicalRepresentation must be non-null
        if (lexicalRepresentation == null) {
            throw new NullPointerException(
                    "Trying to create an xdt:yearMonthDuration with an invalid"
                    + " lexical representation of \"null\"");
        }

        // test lexicalRepresentation against spec regex
        Matcher matcher = XDTSCHEMA_YMD.matcher(lexicalRepresentation);
        if (!matcher.matches()) {
            throw new IllegalArgumentException(
                    "Trying to create an xdt:yearMonthDuration with an invalid"
                    + " lexical representation of \"" + lexicalRepresentation
                    + "\", data model requires days and times only.");
        }

	return newDuration(lexicalRepresentation);
    }

	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:yearMonthDuration</code> using the specified milliseconds as defined in
	 * <a href="http://www.w3.org/TR/xpath-datamodel#yearMonthDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:yearMonthDuration</a>.</p>
	 * 
	 * <p>The datatype <code>xdt:yearMonthDuration</code> is a subtype of <code>xs:duration</code>
	 * whose lexical representation contains only year and month components.
	 * This datatype resides in the namespace {@link javax.xml.XMLConstants#W3C_XPATH_DATATYPE_NS_URI}.</p>
	 * 
     * <p>Both values are set by computing their values from the specified milliseconds
     * and are availabe using the <code>get</code> methods of  the created {@link Duration}.
     * The values conform to and are defined by:</p>
     * <ul>
     *   <li>ISO 8601:2000(E) Section 5.5.3.2 Alternative format</li>
     *   <li><a href="http://www.w3.org/TR/xmlschema-2/#isoformats">
     *     W3C XML Schema 1.0 Part 2, Appendix D, ISO 8601 Date and Time Formats</a>
     *   </li>
     *   <li>{@link XMLGregorianCalendar}  Date/Time Datatype Field Mapping Between XML Schema 1.0 and Java Representation</li>
     * </ul>
     * 
	 * <p>The default start instance is defined by {@link GregorianCalendar}'s use of the start of the epoch: i.e.,
	 * {@link java.util.Calendar#YEAR} = 1970,
	 * {@link java.util.Calendar#MONTH} = {@link java.util.Calendar#JANUARY},
	 * {@link java.util.Calendar#DATE} = 1, etc.
	 * This is important as there are variations in the Gregorian Calendar,
	 * e.g. leap years have different days in the month = {@link java.util.Calendar#FEBRUARY}
	 * so the result of {@link Duration#getMonths()} can be influenced.</p>
	 * 
     * <p>Any remaining milliseconds after determining the year and month are discarded.</p>
	 * 
	 * @param durationInMilliseconds Milliseconds of <code>Duration</code> to create.
	 * 
	 * @return New <code>Duration</code> created using the specified <code>durationInMilliseconds</code>.
	 */
    public Duration newDurationYearMonth(
            final long durationInMilliseconds) {

        // create a Duration that only has sign, year & month
        // Duration is immutable, so need to create a new Duration
        // implementations may override this method in a more efficient way
        Duration fullDuration = newDuration(durationInMilliseconds);
        boolean isPositive = (fullDuration.getSign() == -1) ? false : true;
        BigInteger years =
            (BigInteger) fullDuration.getField(DatatypeConstants.YEARS);
        if (years == null) { years = BigInteger.ZERO; }
        BigInteger months =
            (BigInteger) fullDuration.getField(DatatypeConstants.MONTHS);
        if (months == null) { months = BigInteger.ZERO; }

        return newDurationYearMonth(isPositive, years, months);
    }

	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:yearMonthDuration</code> using the specified
	 * <code>year</code> and <code>month</code> as defined in
	 * <a href="http://www.w3.org/TR/xpath-datamodel#yearMonthDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:yearMonthDuration</a>.</p>
	 * 
     * <p>The XML Schema specification states that values can be of an arbitrary size.
     * Implementations may chose not to or be incapable of supporting arbitrarily large and/or small values.
     * An {@link UnsupportedOperationException} will be thrown with a message indicating implementation limits
     * if implementation capacities are exceeded.</p>
     * 
     * <p>A <code>null</code> value indicates that field is not set.</p>
     * 
     * @param isPositive Set to <code>false</code> to create a negative duration. When the length
     *   of the duration is zero, this parameter will be ignored.
	 * @param year Year of <code>Duration</code>.
	 * @param month Month of <code>Duration</code>.
	 * 
	 * @return New <code>Duration</code> created using the specified <code>year</code> and <code>month</code>.
	 * 
	 * @throws IllegalArgumentException If the values are not a valid representation of a
	 * <code>Duration</code>: if all of the fields (year, month) are null or
	 * if any of the fields is negative.
	 * @throws UnsupportedOperationException If implementation cannot support requested values.
	 */	
	public Duration newDurationYearMonth(
		final boolean isPositive,
		final BigInteger year,
		final BigInteger month) {
			
		return newDuration(
			isPositive,
			year,
			month,
			null, // days
			null, // hours
			null, // minutes
			null  // seconds
		);
	}

	/**
	 * <p>Create a <code>Duration</code> of type <code>xdt:yearMonthDuration</code> using the specified
	 * <code>year</code> and <code>month</code> as defined in
	 * <a href="http://www.w3.org/TR/xpath-datamodel#yearMonthDuration">
	 *   XQuery 1.0 and XPath 2.0 Data Model, xdt:yearMonthDuration</a>.</p>
	 * 
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
     * @param isPositive Set to <code>false</code> to create a negative duration. When the length
     *   of the duration is zero, this parameter will be ignored.
	 * @param year Year of <code>Duration</code>.
	 * @param month Month of <code>Duration</code>.
	 * 
	 * @return New <code>Duration</code> created using the specified <code>year</code> and <code>month</code>.
	 * 
	 * @throws IllegalArgumentException If the values are not a valid representation of a
	 * <code>Duration</code>: if any of the fields (year, month) is negative.
	 */	
	public Duration newDurationYearMonth(
		final boolean isPositive,
		final int year,
		final int month) {
			
		return newDurationYearMonth(
			isPositive,
			BigInteger.valueOf((long) year),
			BigInteger.valueOf((long) month));
		}

	/**
	 * <p>Create a new instance of an <code>XMLGregorianCalendar</code>.</p>
	 * 
     * <p>All date/time datatype fields set to {@link DatatypeConstants#FIELD_UNDEFINED} or null.</p>
     * 
     * @return New <code>XMLGregorianCalendar</code> with all date/time datatype fields set to
     *   {@link DatatypeConstants#FIELD_UNDEFINED} or null.
	 */
	public abstract XMLGregorianCalendar newXMLGregorianCalendar();
	
	/**
	 * <p>Create a new XMLGregorianCalendar by parsing the String as a lexical representation.</p>
	 * 
     * <p>Parsing the lexical string representation is defined in 
     * <a href="http://www.w3.org/TR/xmlschema-2/#dateTime-order">XML Schema 1.0 Part 2, Section 3.2.[7-14].1,
     * <em>Lexical Representation</em>.</a></p>
     * 
     * <p>The string representation may not have any leading and trailing whitespaces.</p>
     * 
     * <p>The parsing is done field by field so that
     * the following holds for any lexically correct String x:</p>
     * <pre>
     * newXMLGregorianCalendar(x).toXMLFormat().equals(x)
     * </pre>
     * <p>Except for the noted lexical/canonical representation mismatches
     * listed in <a href="http://www.w3.org/2001/05/xmlschema-errata#e2-45">
     * XML Schema 1.0 errata, Section 3.2.7.2</a>.</p>
	 * 
	 * @param lexicalRepresentation Lexical representation of one the eight XML Schema date/time datatypes.
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from the <code>lexicalRepresentation</code>.
	 * 
	 * @throws IllegalArgumentException If the <code>lexicalRepresentation</code> is not a valid <code>XMLGregorianCalendar</code>.
	 * @throws NullPointerException If <code>lexicalRepresentation</code> is <code>null</code>.
	 */
	public abstract XMLGregorianCalendar newXMLGregorianCalendar(final String lexicalRepresentation);
	
	/**
	 * <p>Create an <code>XMLGregorianCalendar</code> from a {@link GregorianCalendar}.</p> 
	 *
	 * <table border="2" rules="all" cellpadding="2">
	 *   <thead>
	 *     <tr>
	 *       <th align="center" colspan="2">
	 *          Field by Field Conversion from
	 *          {@link GregorianCalendar} to an {@link XMLGregorianCalendar} 
	 *       </th>
	 *     </tr>
	 *     <tr>
	 *        <th><code>java.util.GregorianCalendar</code> field</th>
	 *        <th><code>javax.xml.datatype.XMLGregorianCalendar</code> field</th>
	 *     </tr>
	 *   </thead>
	 *   <tbody>
	 *     <tr>
	 *       <td><code>ERA == GregorianCalendar.BC ? -YEAR : YEAR</code></td>
	 *       <td>{@link XMLGregorianCalendar#setYear(int year)}</td>
	 *     </tr>
	 *     <tr>
	 *       <td><code>MONTH + 1</code></td>
	 *       <td>{@link XMLGregorianCalendar#setMonth(int month)}</td>
	 *     </tr>
	 *     <tr>
	 *       <td><code>DAY_OF_MONTH</code></td>
	 *       <td>{@link XMLGregorianCalendar#setDay(int day)}</td>
	 *     </tr>
	 *     <tr>
	 *       <td><code>HOUR_OF_DAY, MINUTE, SECOND, MILLISECOND</code></td>
	 *       <td>{@link XMLGregorianCalendar#setTime(int hour, int minute, int second, BigDecimal fractional)}</td>
	 *     </tr>
	 *     <tr>
	 *       <td>
	 *         <code>(ZONE_OFFSET + DST_OFFSET) / (60*1000)</code><br/>
	 *         <em>(in minutes)</em>
	 *       </td>
	 *       <td>{@link XMLGregorianCalendar#setTimezone(int offset)}<sup><em>*</em></sup>
	 *       </td>
	 *     </tr>
	 *   </tbody>
	 * </table>
	 * <p><em>*</em>conversion loss of information. It is not possible to represent 
	 * a <code>java.util.GregorianCalendar</code> daylight savings timezone id in the 
	 * XML Schema 1.0 date/time datatype representation.</p>
	 * 
	 * <p>To compute the return value's <code>TimeZone</code> field,
	 * <ul>
	 * <li>when <code>this.getTimezone() != FIELD_UNDEFINED</code>,
	 * create a <code>java.util.TimeZone</code> with a custom timezone id 
	 * using the <code>this.getTimezone()</code>.</li>
	 * <li>else use the <code>GregorianCalendar</code> default timezone value 
	 * for the host is defined as specified by 
	 * <code>java.util.TimeZone.getDefault()</code>.</li></p>     
	 *
	 * @param cal <code>java.util.GregorianCalendar</code> used to create <code>XMLGregorianCalendar</code>
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from <code>java.util.GregorianCalendar</code>
	 *  
	 * @throws NullPointerException If <code>cal</code> is <code>null</code>.
	 */
	public abstract XMLGregorianCalendar newXMLGregorianCalendar(final GregorianCalendar cal);

	/**
	 * <p>Constructor allowing for complete value spaces allowed by 
	 * W3C XML Schema 1.0 recommendation for xsd:dateTime and related 
	 * builtin datatypes. Note that <code>year</code> parameter supports
	 * arbitrarily large numbers and fractionalSecond has infinite 
	 * precision.</p>
	 * 
     * <p>A <code>null</code> value indicates that field is not set.</p>
     * 
	 * @param year of <code>XMLGregorianCalendar</code> to be created.
	 * @param month of <code>XMLGregorianCalendar</code> to be created.
	 * @param day of <code>XMLGregorianCalendar</code> to be created.
	 * @param hour of <code>XMLGregorianCalendar</code> to be created.
	 * @param minute of <code>XMLGregorianCalendar</code> to be created.
	 * @param second of <code>XMLGregorianCalendar</code> to be created.
	 * @param fractionalSecond of <code>XMLGregorianCalendar</code> to be created.
	 * @param timezone of <code>XMLGregorianCalendar</code> to be created.
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from specified values.
	 * 
	 * @throws IllegalArgumentException If any individual parameter's value is outside the maximum value constraint for the field
	 *   as determined by the Date/Time Data Mapping table in {@link XMLGregorianCalendar}
	 *   or if the composite values constitute an invalid <code>XMLGregorianCalendar</code> instance
	 *   as determined by {@link XMLGregorianCalendar#isValid()}.
	 */
	public abstract XMLGregorianCalendar newXMLGregorianCalendar(
		final BigInteger year,
		final int month,
		final int day,
		final int hour,
		final int minute,
		final int second,
		final BigDecimal fractionalSecond,
		final int timezone);
	
	/**
	 * <p>Constructor of value spaces that a
	 * <code>java.util.GregorianCalendar</code> instance would need to convert to an
	 * <code>XMLGregorianCalendar</code> instance.</p>
	 *    
	 * <p><code>XMLGregorianCalendar eon</code> and 
	 * <code>fractionalSecond</code> are set to <code>null</code></p>
	 *
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
	 * @param year of <code>XMLGregorianCalendar</code> to be created.
	 * @param month of <code>XMLGregorianCalendar</code> to be created.
	 * @param day of <code>XMLGregorianCalendar</code> to be created.
	 * @param hour of <code>XMLGregorianCalendar</code> to be created.
	 * @param minute of <code>XMLGregorianCalendar</code> to be created.
	 * @param second of <code>XMLGregorianCalendar</code> to be created.
	 * @param millisecond of <code>XMLGregorianCalendar</code> to be created.
	 * @param timezone of <code>XMLGregorianCalendar</code> to be created.
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from specified values.
	 * 
	 * @throws IllegalArgumentException If any individual parameter's value is outside the maximum value constraint for the field
	 *   as determined by the Date/Time Data Mapping table in {@link XMLGregorianCalendar}
	 *   or if the composite values constitute an invalid <code>XMLGregorianCalendar</code> instance
	 *   as determined by {@link XMLGregorianCalendar#isValid()}.
	 */
	public XMLGregorianCalendar newXMLGregorianCalendar(
		final int year,
		final int month,
		final int day,
		final int hour,
		final int minute,
		final int second,
		final int millisecond,
		final int timezone) {
			
		// year may be undefined
		BigInteger realYear = (year != DatatypeConstants.FIELD_UNDEFINED) ? BigInteger.valueOf((long) year) : null;
			
		// millisecond may be undefined
		// millisecond must be >= 0 millisecond <= 1000
		BigDecimal realMillisecond = null; // undefined value
		if (millisecond != DatatypeConstants.FIELD_UNDEFINED) {
			if (millisecond < 0 || millisecond > 1000) {
				throw new IllegalArgumentException(
							"javax.xml.datatype.DatatypeFactory#newXMLGregorianCalendar("
							+ "int year, int month, int day, int hour, int minute, int second, int millisecond, int timezone)"
							+ "with invalid millisecond: " + millisecond
							);
			}
			
			realMillisecond = BigDecimal.valueOf((long) millisecond).movePointLeft(3);
		}
		
		return newXMLGregorianCalendar(
			realYear,
			month,
			day,
			hour,
			minute,
			second,
			realMillisecond,
			timezone
		);
	}

	/**
	 * <p>Create a Java representation of XML Schema builtin datatype <code>date</code> or <code>g*</code>.</p>
	 * 
	 * <p>For example, an instance of <code>gYear</code> can be created invoking this factory 
	 * with <code>month</code> and <code>day</code> parameters set to 
	 * {@link DatatypeConstants#FIELD_UNDEFINED}.</p>
	 * 
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
	 * @param year of <code>XMLGregorianCalendar</code> to be created.
	 * @param month of <code>XMLGregorianCalendar</code> to be created.
	 * @param day of <code>XMLGregorianCalendar</code> to be created.
	 * @param timezone offset in minutes. {@link DatatypeConstants#FIELD_UNDEFINED} indicates optional field is not set.
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from parameter values.
	 * 
	 * @see DatatypeConstants#FIELD_UNDEFINED
	 *
	 * @throws IllegalArgumentException If any individual parameter's value is outside the maximum value constraint for the field
	 *   as determined by the Date/Time Data Mapping table in {@link XMLGregorianCalendar}
	 *   or if the composite values constitute an invalid <code>XMLGregorianCalendar</code> instance
	 *   as determined by {@link XMLGregorianCalendar#isValid()}.
	 */
	public XMLGregorianCalendar newXMLGregorianCalendarDate(
		final int year,
		final int month,
		final int day,
		final int timezone) {
			
		return newXMLGregorianCalendar(
			year,
			month,
			day,
			DatatypeConstants.FIELD_UNDEFINED, // hour
			DatatypeConstants.FIELD_UNDEFINED, // minute
			DatatypeConstants.FIELD_UNDEFINED, // second
			DatatypeConstants.FIELD_UNDEFINED, // millisecond
			timezone);
		}
					
	/**
	 * <p>Create a Java instance of XML Schema builtin datatype <code>time</code>.</p>
	 * 
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
	 * @param hours number of hours
	 * @param minutes number of minutes
	 * @param seconds number of seconds
	 * @param timezone offset in minutes. {@link DatatypeConstants#FIELD_UNDEFINED} indicates optional field is not set.
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from parameter values.
	 * 
	 * @throws IllegalArgumentException If any individual parameter's value is outside the maximum value constraint for the field
	 *   as determined by the Date/Time Data Mapping table in {@link XMLGregorianCalendar}
	 *   or if the composite values constitute an invalid <code>XMLGregorianCalendar</code> instance
	 *   as determined by {@link XMLGregorianCalendar#isValid()}.
	 *  
	 * @see DatatypeConstants#FIELD_UNDEFINED
	 */
	public XMLGregorianCalendar newXMLGregorianCalendarTime(
		final int hours,
		final int minutes,
		final int seconds,
		final int timezone) {
				
		return newXMLGregorianCalendar(
			DatatypeConstants.FIELD_UNDEFINED, // Year
			DatatypeConstants.FIELD_UNDEFINED, // Month
			DatatypeConstants.FIELD_UNDEFINED, // Day
			hours,
			minutes,
			seconds,
			DatatypeConstants.FIELD_UNDEFINED, //Millisecond
			timezone);
	}
				
	/**
	 * <p>Create a Java instance of XML Schema builtin datatype time.</p>
	 * 
     * <p>A <code>null</code> value indicates that field is not set.</p>
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
	 * @param hours number of hours
	 * @param minutes number of minutes
	 * @param seconds number of seconds
	 * @param fractionalSecond value of <code>null</code> indicates that this optional field is not set.
	 * @param timezone offset in minutes. {@link DatatypeConstants#FIELD_UNDEFINED} indicates optional field is not set.
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from parameter values.
	 * 
	 * @see DatatypeConstants#FIELD_UNDEFINED
	 *
	 * @throws IllegalArgumentException If any individual parameter's value is outside the maximum value constraint for the field
	 *   as determined by the Date/Time Data Mapping table in {@link XMLGregorianCalendar}
	 *   or if the composite values constitute an invalid <code>XMLGregorianCalendar</code> instance
	 *   as determined by {@link XMLGregorianCalendar#isValid()}.
	 */
	public XMLGregorianCalendar newXMLGregorianCalendarTime(
		final int hours,
		final int minutes,
		final int seconds,
		final BigDecimal fractionalSecond,
		final int timezone) {
			
		return newXMLGregorianCalendar(
			null, // year
			DatatypeConstants.FIELD_UNDEFINED, // month
			DatatypeConstants.FIELD_UNDEFINED, // day
			hours,
			minutes,
			seconds,
			fractionalSecond,
			timezone);
		}

	/**
	 * <p>Create a Java instance of XML Schema builtin datatype time.</p>
	 * 
     * <p>A {@link DatatypeConstants#FIELD_UNDEFINED} value indicates that field is not set.</p>
     * 
	 * @param hours number of hours
	 * @param minutes number of minutes
	 * @param seconds number of seconds
	 * @param milliseconds number of milliseconds
	 * @param timezone offset in minutes. {@link DatatypeConstants#FIELD_UNDEFINED} indicates optional field is not set.
	 * 
	 * @return <code>XMLGregorianCalendar</code> created from parameter values.
	 * 
	 * @see DatatypeConstants#FIELD_UNDEFINED
	 *
	 * @throws IllegalArgumentException If any individual parameter's value is outside the maximum value constraint for the field
	 *   as determined by the Date/Time Data Mapping table in {@link XMLGregorianCalendar}
	 *   or if the composite values constitute an invalid <code>XMLGregorianCalendar</code> instance
	 *   as determined by {@link XMLGregorianCalendar#isValid()}.
	 */
	public XMLGregorianCalendar newXMLGregorianCalendarTime(
		final int hours,
		final int minutes,
		final int seconds,
		final int milliseconds,
		final int timezone) {
			
		// millisecond may be undefined
		// millisecond must be >= 0 millisecond <= 1000
		BigDecimal realMilliseconds = null; // undefined value
		if (milliseconds != DatatypeConstants.FIELD_UNDEFINED) {
			if (milliseconds < 0 || milliseconds > 1000) {
				throw new IllegalArgumentException(
							"javax.xml.datatype.DatatypeFactory#newXMLGregorianCalendarTime("
							+ "int hours, int minutes, int seconds, int milliseconds, int timezone)"
							+ "with invalid milliseconds: " + milliseconds
							);
			}
			
			realMilliseconds = BigDecimal.valueOf((long) milliseconds).movePointLeft(3);
		}
		
		return newXMLGregorianCalendarTime(
			hours,
			minutes,
			seconds,
			realMilliseconds,
			timezone
		);
	}
}
