[Simple-support] Problem with deserialization empty XML element into generic field

[Yaroslav N. <yar...@is...>]

Hi!

I have a data model with classes both generic and immutable like in code 
snippet below:

package ru.ispras.texterra.core;

import java.io.StringReader;
import java.io.StringWriter;

import org.simpleframework.xml.Element;
import org.simpleframework.xml.core.Persister;

public class SimpleSerializerTestCase {
     public static class SomeGeneric<T> {
         @Element(name = "value")
         private final T value;

         public SomeGeneric(@Element(name = "value") T value) {
             this.value = value;
         }
     }

     public static class SomeConcrete extends SomeGeneric<String> {
         public SomeConcrete(@Element(name = "value") String value) {
             super(value);
         }
     }

     public static void main(String[] args) throws Exception {
         Persister persister = new Persister();
         StringWriter writer = new StringWriter();
         persister.write(new SomeConcrete(""), writer);
         StringReader reader = new StringReader(writer.toString());

         // Exception in thread "main" 
org.simpleframework.xml.core.ValueRequiredException: Empty
         // value for @org.simpleframework.xml.Element(name=value, 
data=false, required=true,
         // type=void) on field 'value' private final java.lang.Object
         // 
ru.ispras.texterra.core.SimpleSerializerTestCase$SomeGeneric.value in class
         // 
ru.ispras.texterra.core.SimpleSerializerTestCase$SomeConcrete at line 2
         SomeConcrete read = persister.read(SomeConcrete.class, reader);
     }
}

org.simpleframework.xml.stream.NodeReader.readValue(InputNode) returns 
null in this case instead of empty string and this leads to 
deserialization fail. Could you suggest any workarounds?