/*
 * The contents of this file are subject to the terms
 * of the Common Development and Distribution License
 * (the "License").  You may not use this file except
 * in compliance with the License.
 *
 * You can obtain a copy of the license at
 * https://jaxp.dev.java.net/CDDLv1.0.html.
 * See the License for the specific language governing
 * permissions and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL
 * HEADER in each file and include the License file at
 * https://jaxp.dev.java.net/CDDLv1.0.html
 * If applicable add the following below this CDDL HEADER
 * with the fields enclosed by brackets "[]" replaced with
 * your own identifying information: Portions Copyright
 * [year] [name of copyright owner]
 */

/*
 * $Id: DatatypeFactory.java,v 1.10 2006/05/19 01:08:42 jeffsuttor Exp $
 * @(#)DatatypeFactory.java	1.17 06/07/13
 *
 * Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
 */

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: 1.10 $, $Date: 2006/05/19 01:08:42 $
 * @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 =