exsltdatetime.java

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/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact [e-mail].
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, Lotus
 * Development Corporation., http://www.lotus.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package org.apache.xalan.lib;


import java.util.Date;
import java.util.TimeZone;
import java.util.Calendar;
import java.text.SimpleDateFormat;
import java.text.DateFormat;
import java.text.ParseException;
import org.apache.xpath.objects.XString;
import org.apache.xpath.objects.XNumber;
import org.apache.xpath.objects.XBoolean;
import org.apache.xpath.objects.XObject;

/**
 * <meta name="usage" content="general"/>
 * This class contains EXSLT dates and times extension functions.
 * It is accessed by specifying a namespace URI as follows:
 * <pre>
 *    xmlns:datetime="http://exslt.org/dates-and-times"
 * </pre>
 * 
 * The documentation for each function has been copied from the relevant
 * EXSLT Implementer page.
 * 
 * @see <a href="http://www.exslt.org/">EXSLT</a>
 */

public class ExsltDatetime
{
    // Datetime formats (era and zone handled separately).
    static final String dt = "yyyy-MM-dd'T'HH:mm:ss";
    static final String d = "yyyy-MM-dd";
    static final String gym = "yyyy-MM";
    static final String gy = "yyyy";
    static final String gmd = "MM-dd";
    static final String gm = "MM";
    static final String gd = "dd";
    static final String t = "HH:mm:ss";

    /**
     * The date:date-time function returns the current date and time as a date/time string. 
     * The date/time string that's returned must be a string in the format defined as the 
     * lexical representation of xs:dateTime in 
     * <a href="http://www.w3.org/TR/xmlschema-2/#dateTime">[3.2.7 dateTime]</a> of
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a>.
     * The date/time format is basically CCYY-MM-DDThh:mm:ss, although implementers should consult
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a> and 
     * <a href="http://www.iso.ch/markete/8601.pdf">[ISO 8601]</a> for details.
     * The date/time string format must include a time zone, either a Z to indicate Coordinated 
     * Universal Time or a + or - followed by the difference between the difference from UTC 
     * represented as hh:mm. 
     */
    public static XString dateTime()
    {
      Calendar cal = Calendar.getInstance();
      Date datetime = cal.getTime();
      // Format for date and time.
      SimpleDateFormat dateFormat = new SimpleDateFormat(dt);
      
      StringBuffer buff = new StringBuffer(dateFormat.format(datetime));
      // Must also include offset from UTF.
      // Get the offset (in milliseconds).
      int offset = cal.get(Calendar.ZONE_OFFSET) + cal.get(Calendar.DST_OFFSET);
      // If there is no offset, we have "Coordinated
      // Universal Time."
      if (offset == 0)
        buff.append("Z");
      else
      {
        // Convert milliseconds to hours and minutes
        int hrs = offset/(60*60*1000);
        // In a few cases, the time zone may be +/-hh:30.
        int min = offset%(60*60*1000);
        char posneg = hrs < 0? '-': '+';
        buff.append(posneg + formatDigits(hrs) + ':' + formatDigits(min));
      }
      return new XString(buff.toString());
    }
    
    /**
     * Represent the hours and minutes with two-digit strings.
     * @param q hrs or minutes.
     * @return two-digit String representation of hrs or minutes.
     */
    private static String formatDigits(int q)
    {
      String dd = String.valueOf(Math.abs(q));
      return dd.length() == 1 ? '0' + dd : dd;
    }

    /**
     * The date:date function returns the date specified in the date/time string given 
     * as the argument. If no argument is given, then the current local date/time, as 
     * returned by date:date-time is used as a default argument. 
     * The date/time string that's returned must be a string in the format defined as the 
     * lexical representation of xs:dateTime in 
     * <a href="http://www.w3.org/TR/xmlschema-2/#dateTime">[3.2.7 dateTime]</a> of
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a>.
     * If the argument is not in either of these formats, date:date returns an empty string (''). 
     * The date/time format is basically CCYY-MM-DDThh:mm:ss, although implementers should consult 
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a> and 
     * <a href="http://www.iso.ch/markete/8601.pdf">[ISO 8601]</a> for details. 
     * The date is returned as a string with a lexical representation as defined for xs:date in 
     * [3.2.9 date] of [XML Schema Part 2: Datatypes]. The date format is basically CCYY-MM-DD, 
     * although implementers should consult [XML Schema Part 2: Datatypes] and [ISO 8601] for details.
     * If no argument is given or the argument date/time specifies a time zone, then the date string 
     * format must include a time zone, either a Z to indicate Coordinated Universal Time or a + or - 
     * followed by the difference between the difference from UTC represented as hh:mm. If an argument 
     * is specified and it does not specify a time zone, then the date string format must not include 
     * a time zone. 
     */
    public static XString date(String datetimeIn)
      throws ParseException
    {
      String[] edz = getEraDatetimeZone(datetimeIn);
      String leader = edz[0];
      String datetime = edz[1];
      String zone = edz[2];
      if (datetime == null || zone == null) 
        return new XString("");
                    
      String[] formatsIn = {dt, d};
      String formatOut = d;
      Date date = testFormats(datetime, formatsIn);
      if (date == null) return new XString("");
      
      SimpleDateFormat dateFormat = new SimpleDateFormat(formatOut);
      dateFormat.setLenient(false);
      String dateOut = dateFormat.format(date);      
      if (dateOut.length() == 0)
          return new XString("");
      else        
        return new XString(leader + dateOut + zone);
    }
    
    
    /**
     * See above.
     */
    public static XString date()
    {
      String datetime = dateTime().toString();
      String date = datetime.substring(0, datetime.indexOf("T"));
      String zone = datetime.substring(getZoneStart(datetime));
      return new XString(date + zone);
    }
    
    /**
     * The date:time function returns the time specified in the date/time string given 
     * as the argument. If no argument is given, then the current local date/time, as 
     * returned by date:date-time is used as a default argument. 
     * The date/time string that's returned must be a string in the format defined as the 
     * lexical representation of xs:dateTime in 
     * <a href="http://www.w3.org/TR/xmlschema-2/#dateTime">[3.2.7 dateTime]</a> of
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a>. 
     * If the argument string is not in this format, date:time returns an empty string (''). 
     * The date/time format is basically CCYY-MM-DDThh:mm:ss, although implementers should consult 
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a> and 
     * <a href="http://www.iso.ch/markete/8601.pdf">[ISO 8601]</a> for details.
     * The date is returned as a string with a lexical representation as defined for xs:time in 
     * <a href="http://www.w3.org/TR/xmlschema-2/#time">[3.2.8 time]</a> of [XML Schema Part 2: Datatypes].
     * The time format is basically hh:mm:ss, although implementers should consult [XML Schema Part 2: 
     * Datatypes] and [ISO 8601] for details. 
     * If no argument is given or the argument date/time specifies a time zone, then the time string 
     * format must include a time zone, either a Z to indicate Coordinated Universal Time or a + or - 
     * followed by the difference between the difference from UTC represented as hh:mm. If an argument 
     * is specified and it does not specify a time zone, then the time string format must not include 
     * a time zone. 
     */
    public static XString time(String timeIn)
      throws ParseException      
    {
      String[] edz = getEraDatetimeZone(timeIn);
      String time = edz[1];
      String zone = edz[2];
      if (time == null || zone == null) 
        return new XString("");
                    
      String[] formatsIn = {dt, d};
      String formatOut =  t;
      Date date = testFormats(time, formatsIn);
      if (date == null) return new XString("");
      SimpleDateFormat dateFormat = new SimpleDateFormat(formatOut);
      String out = dateFormat.format(date);
      return new XString(out + zone);
    }

    /**
     * See above.
     */
    public static XString time()
    {
      String datetime = dateTime().toString();
      String time = datetime.substring(datetime.indexOf("T")+1);
      String zone = datetime.substring(getZoneStart(datetime));      
      return new XString(time + zone);
    } 
       
    /**
     * The date:year function returns the year of a date as a number. If no 
     * argument is given, then the current local date/time, as returned by 
     * date:date-time is used as a default argument.
     * The date/time string specified as the first argument must be a right-truncated 
     * string in the format defined as the lexical representation of xs:dateTime in one 
     * of the formats defined in 
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a>.
     * The permitted formats are as follows: 
     *   xs:dateTime (CCYY-MM-DDThh:mm:ss) 
     *   xs:date (CCYY-MM-DD) 
     *   xs:gYearMonth (CCYY-MM) 
     *   xs:gYear (CCYY) 
     * If the date/time string is not in one of these formats, then NaN is returned. 
     */
    public static XNumber year(String datetimeIn)
      throws ParseException
    {
      String[] edz = getEraDatetimeZone(datetimeIn);
      boolean ad = edz[0].length() == 0; // AD (Common Era -- empty leader)
      String datetime = edz[1];
      if (datetime == null) 
        return new XNumber(Double.NaN);
      
      String[] formats = {dt, d, gym, gy};
      double yr = getNumber(datetime, formats, Calendar.YEAR);
      if (ad || yr == Double.NaN)
        return new XNumber(yr);
      else
        return new XNumber(-yr);
    }
     
    /**
     * See above.
     */
    public static XNumber year()
    {
      Calendar cal = Calendar.getInstance();
      return new XNumber(cal.get(Calendar.YEAR));
    }
    
    /**
     * The date:year function returns the month of a date as a number. If no argument 
     * is given, then the current local date/time, as returned by date:date-time is used 
     * as a default argument. 
     * The date/time string specified as the first argument is a left or right-truncated 
     * string in the format defined as the lexical representation of xs:dateTime in one of 
     * the formats defined in 
     * <a href="http://www.w3.org/TR/xmlschema-2/">[XML Schema Part 2: Datatypes]</a>.
     * The permitted formats are as follows: 
     *    xs:dateTime (CCYY-MM-DDThh:mm:ss) 
     *    xs:date (CCYY-MM-DD) 
     *    xs:gYearMonth (CCYY-MM) 
     * If the date/time string is not in one of these formats, then NaN is returned. 
     */
    public static XNumber monthInYear(String datetimeIn)
      throws ParseException
    {
      String[] edz = getEraDatetimeZone(datetimeIn);
      String datetime = edz[1];
      if (datetime == null)
        return new XNumber(Double.NaN);      
      
      String[] formats = {dt, d, gym};