I'm trying to unmarshall an XML file:

<?xml version="1.0" encoding="UTF-8"?>
<billing nbr="1">
<name>John Smith </name>
<phone>416-429-8888</phone>
<dob>1960-12-12</dob>
</billing>

 into an Java object. But the output I am getting looks like this:



As I need the date in "yyyy-MM-dd" format, I implemented the class DateHandler as follows:
<!DOCTYPE databases PUBLIC
  "-//EXOLAB/Castor Mapping DTD Version 1.0//EN"
  "http://castor.exolab.org/mapping.dtd">
<mapping>
  <class name="Person" auto-complete="true">
  <map-to xml="dob"/>
    <field name="dob" handler="DateHandler" type = "string" />
   </class>
</mapping>

and defaults handler source code is:
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import org.exolab.castor.mapping.AbstractFieldHandler;
import org.exolab.castor.mapping.ExtendedFieldHandler;
import org.exolab.castor.mapping.FieldDescriptor;
import org.exolab.castor.mapping.FieldHandler;
import org.exolab.castor.mapping.GeneralizedFieldHandler;

public class DateHandler extends GeneralizedFieldHandler {

public final DateFormat format = new SimpleDateFormat("yyyy-MM-dd");

public Object convertUponGet(Object value) {
//System.out.println("A3");
//System.out.println(value);
//System.out.println(format.format(value));
return format.format(value);
}

public Object convertUponSet (Object value) {
//System.out.println("A1");
String dateStr = (String) value;
try {
//System.out.println("A2");
Date date1 = (Date) format.parse(dateStr);
//System.out.println("date1 " + date1);
//System.out.println(format.format(date1));
return date1;
} catch (ParseException e) {
throw new RuntimeException(e);
}
}

public Class getFieldType() {
return java.util.Date.class;
}
}

hi,

check out the documentation from castor mailing list on writing custom field handlers..

-----------------------
And the section 6.2 Create your own FieldHandler may include an example of the derivation of GeneralizedFieldHandler class.
---------------------------
&lta name="6.2-Create-your-own-FieldHandler"&gt&lth3&gt6.2 Create your own FieldHandler&lt/h3&gt&lt/a&gt
             
&ltp&gt&ltspan class="bodyGrey"&gtSometimes to handle complex situations you'll need to create your own FieldHandler. Normally a FieldHandler deals with a specific class and field, however generic, reusable FieldHandlers can also be created by extending org.exolab.castor.mapping.GeneralizedFieldHandler (be sure to a Castor version &gt 0.9.4.1 !) or
org.exolab.castor.mapping.AbstractFieldHandler.
The FieldHandler can be specified on the &ltfield&gt element. &lt/span&gt&lt/p&gt
&ltp&gt&ltspan class="bodyGrey"&gtLet's imagine one need to define a specialized date handler if the date format of the Castor's default date handler is not appropriate.
One could define a new specialized date handler like the MMddYYYYDateHandler below.&lt/span&gt&lt/p&gt
            &lttable border="1" cellpadding="4"&gt
            &lttr&gt &ltth&gt MMddYYYYDateHandler.java &lt/th&gt &lt/tr&gt
            &lttr&gt &lttd bgcolor="#CCCCCC"&gt&ltspan class="bodyGrey" bgcolor="#CCCCCC"&gt
             &ltspan class="bodyBlack"&gt
            &ltpre&gt
import org.exolab.castor.mapping.GeneralizedFieldHandler;
import java.text.SimpleDateFormat;
import java.text.ParsePosition;
public class MMddYYYYDateHandler extends GeneralizedFieldHandler {
  private static final SimpleDateFormat DateFormatter = new SimpleDateFormat("MM:dd:yyyy");
  static {
    DateFormatter.setLenient(false);
  }
  /**
   * This method is used to convert the value (from java.util.Date
   * to String) when the getValue method is called.
   * The getValue method will obtain the actual field value
   * from given 'parent' object. This convert method is then invoked
   * with the field's value. The value returned from this
   * method will be the actual value returned by getValue method.
   *
   * @param value the object value to convert after performing a get
   * operation
   * @return the converted value.
   */
  public Object convertUponGet(Object value) {
    return DateFormatter.format((java.util.Date) value);
  }


     
  /**
   * Returns the class type for the field that this GeneralizedFieldHandler
   * converts to and from. This should be the type that is used in the
   * object model.
   *
   * @return the class type of of the field
   */
  public Class getFieldType() {
    return java.util.Date.class;
  }
  /**
   * This method is used to convert the value (from String to
   * java.util.Date) when the setValue method is called.
   * The setValue method will call this method to obtain
   * the converted value. The converted value will then be used as
   * the value to set for the field.
   *
   * @param value the object value to convert before performing a set
   * operation
   * @return the converted value.
   */
  public Object convertUponSet(Object value) {
    return DateFormatter.parse((String) value, new ParsePosition(0));
  }
}
&lt/pre&gt&lt/span&gt &lt/span&gt&lt/td&gt &lt/tr&gt &lt/table&gt


&ltp&gt&ltspan class="bodyGrey"&gtFor using this handler, a &ltfield&gt element should be defined like :
                &ltspan class="bodyBlack"&gt&ltpre&gt
          &ltfield name="birthDate" type="string" handler="MMddYYYDateHandler"/&gt
          &lt/pre&gt&lt/span&gt
The &ltspan class="bodyBlack"&gttype="string"&lt/span&gt defines the type that
the MMddYYYDateHandler is expecting to receive. This special FieldHandler will convert the XML/string value into a Java/Date value
and vice versa.&lt/span&gt&lt/p&gt
&ltp&gt&ltspan class="bodyGrey"&gt
The convertUponGet method is only be called during marshalling and validation
(note that you can disable validation using [marshaller#setValidation(false)]),
so the value will always be the instance from the object model and not
from the XML.&ltbr&gt&ltbr&gt
The convertUponGet method is also used when
comparing values for reuseable objects for unmarshalling.
If you are unmarshalling and you have setReuseObjects = true, simple
values are compared to see if the value needs to be set, so an
additional call might be done then as well.&ltbr&gt&ltbr&gt


The convertUponSet method is only used during unmarshalling.
The value from the XML file will be passed into convertUponSet during
unmarshalling.
&lt/span&gt&lt/p&gt



------------


Bhagvan K
http://www.architectcorner.com