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 * 4. Products derived from this Software may not be called "Exolab"
 *    nor may "Exolab" appear in their names without prior written
 *    permission of Intalio, Inc. Exolab is a registered
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 * 5. Due credit should be given to the Exolab Project
 *    (http://www.exolab.org/).
 *
 * THIS SOFTWARE IS PROVIDED BY INTALIO, INC. AND CONTRIBUTORS
 * ``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
 * INTALIO, INC. 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.
 *
 * Copyright 2001 (C) Intalio, Inc. All Rights Reserved.
 *
 * $Id: GMonth.java,v 1.2 2005/03/05 13:41:56 mfuchs Exp $
 * Date         Author              Changes
 * 04/18/2002   Arnaud              String constructor
 * 05/24/2001   Arnaud Blandin      Created
 */

package org.exolab.castor.types;

import java.text.SimpleDateFormat;
import java.text.ParseException;
import java.util.SimpleTimeZone;
import java.util.TimeZone;

/**
 * Describe an XML schema gMonth type.
 * <p>The format is defined by W3C XML Schema Recommendation and ISO8601
 * i.e <tt>--MM--(Z|(+|-)hh:mm)</tt>
 * @author <a href="mailto:blandin@intalio.com">Arnaud Blandin</a>
 * @version $Revision: 1.2 $
 */

public class GMonth extends GMonthDay {

   /**
    * The GMOnth format
    */
    private static final String MONTH_FORMAT = "--MM--";

    private static final String BAD_GMONTH = "Bad gMonth format: ";

      /**
     * public only for the generated source code
     */
    public GMonth() {
    }

    /**
     * Constructs a XML Schema GMonth instance given all the values of
     * the different fields.
     * By default a GMonth is not UTC and is local.
     * @param month the month value.
     */

    public GMonth(short month) {
        setMonth(month);
    }

    /**
     * Constructs a XML Schema GMonth instance given all the values of
     * the different fields.
     * By default a GMonth is not UTC and is local.
     * @param month the month value.
     */

    public GMonth(int month) {
        setMonth((short)month);
    }

   /**
    * Constructs a GMonth from a string value.
    * @param gmonth the string representation of the GMonth to instantiate
    */
    public GMonth(String gmonth) throws ParseException {
        this();
        parseGMonthInternal(gmonth, this);
    }



    /**
     * converts this GMonth into a local java Date.
     * @return a local date representing this Date.
     */
    public java.util.Date toDate(){

        java.util.Date date = null;
        SimpleDateFormat df = new SimpleDateFormat(MONTH_FORMAT);
        // Set the time zone
        if ( isUTC() ) {
            SimpleTimeZone timeZone = new SimpleTimeZone(0,"UTC");
            int offset = 0;
            offset = (int) ( (this.getZoneMinute() + this.getZoneHour()*60)*60*1000);
            offset = isZoneNegative() ? -offset : offset;
            timeZone.setRawOffset(offset);
            timeZone.setID(TimeZone.getAvailableIDs(offset)[0]);
            df.setTimeZone(timeZone);
        }

        try {
            date = df.parse(this.toString());
        } catch (ParseException e) {
           //this can't happen since toString() should return the proper
           //string format
           e.printStackTrace();
           return null;
        }
        return date;
    }//toDate()

    /**
     * convert this GMonth to a string
     * The format is defined by W3C XML Schema recommendation and ISO8601
     * i.e --MM--(Z|(+|-)hh:mm)
     * @return a string representing this Date
     */
     public String toString() {

        StringBuffer result = new StringBuffer();
        result.append('-');
        result.append('-');

        result.append(this.getMonth());
        if (result.length() == 3)
            result.insert(2,0);

        result.append('-');
        result.append('-');

        if (isUTC()) {
            //By default we append a 'Z' to indicate UTC
            if ( (this.getZoneHour() == 0) && (this.getZoneMinute() ==0) )
                result.append('Z');
            else {
                StringBuffer timeZone = new StringBuffer();
                if (isZoneNegative())
                   timeZone.append('-');
                else timeZone.append('+');

                if ((this.getZoneHour()/10) == 0)
                    timeZone.append(0);
                timeZone.append(this.getZoneHour());

                timeZone.append(':');
                if ((this.getZoneMinute()/10) == 0)
                    timeZone.append(0);
                timeZone.append(this.getZoneMinute());

               result.append(timeZone.toString());
               timeZone = null;
            }
        }
        return result.toString();

    }//toString

    /**
     * parse a String and convert it into an java.lang.Object
     * @param str the string to parse
     * @return an Object represented by the string
     * @throws ParseException a parse exception is thrown if the string to parse
     *                        does not follow the rigth format (see the description
     *                        of this class)
     */

    public static Object parse(String str) throws ParseException {
        return parseGMonth(str);
    }

    /**
     * parse a String and convert it into a GMonth.
     * @param str the string to parse
     * @return the Date represented by the string
     * @throws ParseException a parse exception is thrown if the string to parse
     *                        does not follow the rigth format (see the description
     *                        of this class)
     */
    public static GMonth parseGMonth(String str) throws ParseException {
         GMonth result = new GMonth();
         return parseGMonthInternal(str, result);
    }

    private static GMonth parseGMonthInternal(String str, GMonth result) throws ParseException {

        if (str == null)
             throw new IllegalArgumentException("The string to be parsed must not "
                                                +"be null.");
        if (result == null)
            result = new GMonth();
        char[] chars = str.toCharArray();
        int idx = 0;

        boolean hasNumber = false;
        boolean has2Digits = false;
        short number = -1;
        short number2 = 0;
        //-- parse flags
        //-- ----(char): = b111111 (63)
        int flags = 63;

        while (idx < chars.length) {
             char ch = chars[idx++];

             switch (ch) {

                 case '-' :
                       if ( (flags == 63) && (number == -1))
                          flags = 31;
                       else if ((flags == 31)  && (number == -1))
                          flags = 15;
                       else if (flags == 15) {
                           if (has2Digits) {
                               result.setMonth(number);
                               flags = 7;
                               number = -1;
                           } else throw new ParseException(BAD_GMONTH+str+"\nThe month field must have 2 digits.",idx);
                       }
                       else if ( (flags == 7) && (number == -1))
                           flags = 3;
                       else if ( (flags == 3) && (number == -1)) {
                           result.setUTC();
                           result.setZoneNegative(true);
                           flags = 1;
                       }
                       else throw new ParseException(BAD_GMONTH+str+"\nA gMonth must follow the pattern --MM--(Z|((+|-)hh:mm)).",idx);
                       hasNumber = false;
                       has2Digits = false;
                       break;

                 case 'Z' :
                        if (flags != 3)
                         throw new ParseException(BAD_GMONTH+str+"\n'Z' "+WRONGLY_PLACED,idx);
                      else
                          result.setUTC();
                      break;

                case '+' :
                    if (flags != 3)
                        throw new ParseException(BAD_GMONTH+str+"\n'+' "+WRONGLY_PLACED,idx);
                    else {
                          result.setUTC();
                          flags = 1;
                    }
                    hasNumber = false;
                    has2Digits = false;
                    break;

                 case ':' :
                     if (flags != 1)
                        throw new ParseException(BAD_GMONTH+str+"\n':' "+WRONGLY_PLACED,idx);
                     number2 = number;
                     number = -1;
                     flags = 0;
                     hasNumber = false;
                     has2Digits = false;
                     break;

                 default:
                    //make sure we have a digit
                    if ( ('0' <= ch) && (ch <= '9')) {
                        if (hasNumber) {
                            number = (short)((number*10)+(ch-48));
                            has2Digits = true;
                        }
                        else {
                            hasNumber = true;
                            number = (short) (ch-48);
                        }
                    }
                    else
                        throw new ParseException (str+": Invalid character: "+ch, idx);
                    break;
             }//switch
        }//while
        if (flags!=3 && flags != 0)
            throw new ParseException(BAD_GMONTH+str+"\nA gMonth must follow the pattern --MM--(Z|((+|-)hh:mm)).",idx);

        else if (flags == 0) {
            if (number != -1)
                result.setZone(number2,number);
            else throw new ParseException(str+"\n In a time zone, the minute field must always be present.",idx);
        }

        return result;

    }//parse

    ///////////////////////////DISALLOW DAY METHODS///////////////////////////
     public short getDay() {
        String err = "GMonth: couldn't access to the Day field.";
        throw new OperationNotSupportedException(err);
    }

    public void setDay(short day) {
        String err = "GMonth: couldn't access to the Day field.";
        throw new OperationNotSupportedException(err);
    }
}