Implementing KSOAP Marshal Interface

Another poorly documented spot in KSOAP: marshaling arguments. In KSOAP, you need to implement an interface called Marshal so that the XML parser would know how to serialize and deserialize objects you are trying to pass through the web service.

Strangely enough, object types like "double" and "Date" need to be manually marshaled! This is why I decided my code examples to show how to marshal dates and doubles. So here it goes:

package Marshals;

import java.io.IOException;

import org.ksoap2.serialization.Marshal;
import org.ksoap2.serialization.PropertyInfo;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;
/**
* 
* @author Vladimir
* Used to marshal Doubles - crucial to serialization for SOAP
*/
public class MarshalDouble implements Marshal 
{


    public Object readInstance(XmlPullParser parser, String namespace, String name, 
            PropertyInfo expected) throws IOException, XmlPullParserException {
        
        return Double.parseDouble(parser.nextText());
    }


    public void register(SoapSerializationEnvelope cm) {
         cm.addMapping(cm.xsd, "double", Double.class, this);
        
    }


    public void writeInstance(XmlSerializer writer, Object obj) throws IOException {
           writer.text(obj.toString());
        }
    
}

As you can see, the code here is so trivial that I am honestly surprised why it does not come out of the box like it does for ints.
The next example shows how to Marhsal Dates with KSOAP:

package Marshals;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import org.kobjects.isodate.IsoDate;
import org.ksoap2.serialization.Marshal;
import org.ksoap2.serialization.PropertyInfo;
import org.ksoap2.serialization.SoapSerializationEnvelope;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import org.xmlpull.v1.XmlSerializer;

/**
 * 
 * @author Vladimir
 * Used to marshal Dates - crucial to serialization for SOAP
 */
public class MarshalDate implements Marshal
{

        public Object readInstance(XmlPullParser parser, String namespace, String name, 
                PropertyInfo expected) throws IOException, XmlPullParserException {
            
            return IsoDate.stringToDate(parser.nextText(), IsoDate.DATE_TIME);
            
            
        }


        public void register(SoapSerializationEnvelope cm) {
             cm.addMapping(cm.xsd, "DateTime", Date.class, this);
            
        }


        public void writeInstance(XmlSerializer writer, Object obj) throws IOException {
             writer.text(IsoDate.dateToString((Date) obj, IsoDate.DATE_TIME));
            }
    
}

As you probably assume, in order to tell KSOAP how to use the marshaling, you need to use the register() method in the following manner:

String MethodName = "GetEventById";
SoapObject request = GetSoapObject(MethodName);
AddProperty(request, Event);
SoapSerializationEnvelope envelope = GetEnvelope(request);
        
envelope.addMapping(NAMESPACE, "Event",Event.getClass());

MarshalDate md = new MarshalDate();
md.register(envelope);
       
SoapObject response =  MakeCall(URL,envelope,NAMESPACE,MethodName);

Basically that is all you need to get started with KSOAP marshaling.