We just have to change the file flex.messaging.io.amf.Amf3Output.java in BlazeDS source. All we are doing here is when an object is of type Long,Double,Integer,Float or Short and is null we convert the return value to Double.NaN in the DataOutputStream. This ensures that Flex gets Double.NaN on the receiving end. Note: The same change below should be made to flex.messaging.io.amf.Amf0Output.java if you are using the AMF0 format for ActionScript 1.0 and 2.0.

Class Amf3Output.java

protected void writePropertyProxy(PropertyProxy proxy, Object instance) throws IOException
{

else if (propertyNames != null)
{
Iterator it = propertyNames.iterator();
while (it.hasNext())
{
String propName = (String)it.next();
Object value = null;
value = proxy.getValue(instance, propName);

// IDS – Start of changes – 01/10/2010
value = proxy.getValue(instance, propName);
if (IdsObjectHelper.isNullNumber(instance,propName,value))
writeAMFDouble(Double.NaN);
else
// IDS – End of Changes – 01/10/2010
writeObjectProperty(propName, value);

}
}

writeObjectEnd();
}

And the helper class:

package com.ids.foundation.flex.messaging.io;

import java.lang.reflect.Field;

public class IdsObjectHelper {

static boolean useCustomLogic = true;

public static boolean isNullNumber(Object object, String propName, Object value) {
Field[] fields = object.getClass().getDeclaredFields();

if (value != null || !useCustomLogic)
return false;

for (int index = 0; index < fields.length; index++) {
if (fields[index].getName().equals(propName)) {
if (fields[index].getType().isInstance(new Integer(0)))
return true;
else if (fields[index].getType().isInstance(new Double(0)))
return true;
else if (fields[index].getType().isInstance(new Long(0)))
return true;
else if (fields[index].getType().isInstance(new Float(0)))
return true;
else if (fields[index].getType().isInstance(new Short((short)0)))
return true;
else
return false;
}
}
return false;
}

}

I have implemented your solution and it works like a charm. Thanks a lot!

This seems to be a big bug with BlazeDS, so I hope they will fix it soon.

Kim

Is it support both ways? means, from the Java to AS and from the AS to Java ?

i understand that it simply upgrade the decoder , but what about the encoder?

Ziv

Please read my next post: rebuild of the BlazeDS can be avoided by using so called Custom Marshaller.
In that case you would resolve the issue with two classes: CustomMarshaller, that gets configured per Endpoint in the services-config.xml and NumberDecoder.

WBR,
Victor

Nono